ULTRA-SMALL PACKAGE PWM CONTROL, PWM/PFM …56,57,58_e.pdf · Rev.1.2-12 Seiko Instruments Inc. 1 The S-8355/56/57/58 Series is a CMOS step-up switching regulator which mainly consists

Rev.1.2-12

Seiko Instruments Inc. 1

The S-8355/56/57/58 Series is a CMOS step-up switching regulatorwhich mainly consists of a reference voltage source, an oscillationcircuit, an error amplifier, a phase compensation circuit, a PWMcontrol circuit (S-8355/57) and a PWM/PFM switching control circuit(S-8356/58). With an external low-ON-resistance Nch Power MOS,this product is applicable to applications requiring high efficiency andhigh output current.The S-8355/57 Series realizes low ripple, high efficiency, andexcellent transient characteristics with the PWM control circuit whoseduty ratio can vary from 0 % to 83 % (from 0 % to 78 % for 250 kHzand 300 kHz models), the best-designed error amplifier and phasecompensation circuits.The S-8356/58 Series switches its operation to the PFM control circuitwhose duty ratio is 15 % with to the PWM/PFM switching controlcircuit under a light load and to prevent decline in the efficiency by ICoperation current.

! Features

• Low voltage operation: Start-up is guaranteed from 0.9 V(IOUT =1 mA )• Low current consumption: During operation: 25.9 µA (3.3 V, 100 kHz, typ.)

During shutdown: 0.5 µA (max.)• Duty ratio: Built-in PWM/PFM switching control circuit (S-8356/58)

15 to 83 % (100 kHz models), 15 to 78 % (250 kHz and 300 kHz models)• External parts: coil, diode, capacitor, and transistor• Output voltage: 0.1 V step setting is available between 1.5 and 6.5 V (for VDD/VOUT separate types) or

2.0 and 6.5 V (for other than VDD/VOUT separate types). Accuracy of ±2.4 %.• Oscillation frequency: 100, 250, and 300 kHz• Soft start function: 6 ms (100 kHz, typ.)• Shutdown function

!"Packages

• SOT-23-3 (Package code : MP003-A)• SOT-23-5 (Package code : MP005-A)• SOT-89-3 (Package code : UP003-A)• 6-Pin SNB(B) (Package code : BD006-A)

! Applications

• Power supplies for portable equipment such as digital cameras, electronic notebooks, and PDAs• Power supplies for audio equipment such as portable CD/MD players• Constant voltage power supplies for cameras, video equipment, and communications equipment• Power supplies for microcomputers

S-8355/56/57/58 SeriesULTRA-SMALL PACKAGE PWM CONTROL,PWM/PFM SWITCHING CONTROLSTEP-UP SWITCHING REGULATOR

ULTRA-SMALL PACKAGE PWM CONTROL, PWM/PFM SWITCHING CONTROL STEP-UP SWITCHING REGULATORS-8355/56/57/58 Series Rev. 1.2-12

2 Seiko Instruments Inc.

! Block Diagram

! Selection Guide

1. Function List

Product name Controlsystem

Switchingfrequency

(kHz)

Shutdownfunction

VDD/VOUTseparate

typePackage Application

S-8355KxxMC PWM 100 Yes Yes SOT-23-5 Application which needs an variable output voltage and a shutdown function

S-8355LxxMC/BD 250 Yes Yes SOT-23-5 / 6-Pin SNB(B) Application which needs an variable output voltage, a shutdown functionand a thin coil

S-8355MxxMC/BD 300 Yes Yes SOT-23-5 / 6 Pin-SNB(B) Application which needs an variable output voltage, a shutdown functionand a thin coil

S-8357BxxMC 100 Yes SOT-23-5 Application which needs a shutdown functionS-8357BxxMA 100 SOT-23-3 Application with an unnecessary shutdown functionS-8357BxxUA 100 SOT-89-3 Application with an unnecessary shutdown functionS-8357ExxMC 100 Yes SOT-23-5 Application which adjusts output voltage by external resistorS-8357FxxMC/BD 300 Yes SOT-23-5 / 6-Pin SNB(B) Application which needs a shutdown function and a thin coilS-8357GxxMC/BD 300 Yes SOT-23-5 / 6-Pin SNB(B) Application which needs an variable output voltage and a thin coilS-8357HxxMC/BD 250 Yes SOT-23-5 / 6-Pin SNB(B) Application which needs a shutdown function and a thin coil

S-8357JxxMC/BD 250 Yes SOT-23-5 / 6-Pin SNB(B) Application which needs an variable output voltage with an external resistorand a thin coil

S-8356KxxMC PWM/PFMswitching 100 Yes Yes SOT-23-5 Application which needs an variable output voltage and a shutdown function

S-8356LxxMC/BD 250 Yes Yes SOT-23-5 / 6-Pin SNB(B) Application which needs an variable output voltage, a shutdown functionand a thin coil

S-8356MxxMC/BD 300 Yes Yes SOT-23-5 / 6-Pin SNB(B) Application which needs an variable output voltage, a shutdown functionand a thin coil

S-8358BxxMC 100 Yes SOT-23-5 Application which needs a shutdown functionS-8358BxxMA 100 SOT-23-3 Application with an unnecessary shutdown functionS-8358BxxUA 100 SOT-89-3 Application with an unnecessary shutdown functionS-8358ExxMC 100 Yes SOT-23-5 Application which adjusts output voltage by external resistorS-8358FxxMC/BD 300 Yes SOT-23-5 / 6-Pin SNB(B) Application which needs a shutdown function and a thin coilS-8358GxxMC/BD 300 Yes SOT-23-5 / 6-Pin SNB(B) Application which needs an variable output voltage and a thin coilS-8358HxxMC/BD 250 Yes SOT-23-5 / 6-Pin SNB(B) Application which needs a shutdown function and a thin coil

S-8358JxxMC/BD 250 Yes SOT-23-5 / 6-Pin SNB(B) Application which needs an variable output voltage with an external resistorand a thin coil

Figure 1 Block Diagram

-+

IC internalpower supply

VOUT

EXT

VSS

PWM or PWM /PFM switching control circuit

Soft startbuilt-in referencepower supply

Phasecompensationcircuit

Oscillation Circuit

-+

EXT

VOUT

VSS

VDD

IC internalpowersupply




Oscillation Circuit

-+

IC internalpower supply

VOUT

VSS



EXT

Oscillation Circuit

ON/ OFF


-+


IC internalpowersupply

VOUT

EXT

VSSPhasecompensationcircuit

VDD

Oscillation Circuit

ON/ OFF


(1) S-8357/58 Series B, H, F Type (No shutdown function) (2) S-8357/58 Series B, H, F Type (Shutdown function included)

(3) S-8357/58 Series E, J, G Type (VDD/VOUT separate type) (4) S-8355/56 Series K, L, M Type

ULTRA-SMALL PACKAGE PWM CONTROL, PWM/PFM SWITCHING CONTROL STEP-UP SWITCHING REGULATORRev. 1.2-12 S-8355/56/57/58 Series


2. Product Name

S-835 x x xx xx - xxx - Tx

IC direction in tape specificationT2 ; SOT-23-3, SOT-23-5, SOT-89-3TF ; 6-Pin SNB(B)

Product name (abbreviation)Package name (abbreviation)

MA ; SOT-23-3MC ; SOT-23-5UA ; SOT-89-3BD ; 6 Pin-SNB(B)

Output voltage (× 10) 18 to 50 (1.8 to 5.0 V)Product type

B ; Normal product, fOSC= 100 kHz (S-8357/58)H ; Normal product, fOSC = 250 kHz (S-8357/58)F ; Normal product, fOSC = 300 kHz (S-8357/58)E ; VDD/VOUT separate type, fOSC = 100 kHz (S-8357/58)J ; VDD/VOUT separate type, fOSC = 250 kHz (S-8357/58)G ; VDD/VOUT separate type, fOSC = 300 kHz (S-8357/58)K ; Shutdown function + VDD/VOUT separate type, fOSC = 100 kHz (S-8355/56)

L ; Shutdown function + VDD/VOUT separate type, fOSC = 250 kHz (S-8355/56)M ; Shutdown function + VDD/VOUT separate type, fOSC = 300 kHz (S-8355/56)

Control system5 or 7 ; PWM control6 or 8 ; PWM/PFM switching control

3. Package and Function List by Product Type

Series name Type Package name(abbreviation)

ShutdownfunctionYes / No

VDD/VOUTseparate type

Yes / No

S-8355 SeriesS-8356 Series

K, L, M(Shutdown function + VDD/VOUT separate type) K = 100 kHz, L = 250 kHz, M = 300 kHz

MCBD

Yes Yes

MAUA

NoB, H, F(Normal product) B = 100 kHz, H = 250 kHz, F = 300 kHz MC

BDYes

No

S-8357 SeriesE, J, G(VDD/VOUT separate type) E = 100 kHz, J = 250 kHz, G = 300 kHz

MCBD

No Yes

MAUA

NoB, H, F(Normal product) B = 100 kHz, H = 250 kHz, F = 300 kHz MC

BDYes

No

S-8358 SeriesE, J, G(VDD /VOUT separate type) E=100 kHz, J=250 kHz, G=300 kHz

MCBD

No Yes



4. Product Name List

Output voltage (V) S-8355KxxMC Series S-8355MxxBD Series S-8355MxxMC Series

1.8 S-8355K18MC-NAD-T2 S-8355M18BD-MCD-TF S-8355M18MC-MCD-T2

5.0

Output voltage (V) S-8356KxxMC Series S-8356MxxBD Series S-8356MxxMC Series

1.8 S-8356K18MC-NED-T2 S-8356M18BD-MED-TF S-8356M18MC-MED-T2

5.0 S-8356M50MC-MFJ-T2

Output voltage (V) S-8357BxxMC Series S-8357FxxMC Series S-8357GxxMC Series

3.3 S-8357B33MC-NIS-T2 S-8357F33MC-MGS-T2

5.0 S-8357B50MC-NJ J-T2 S-8357F50MC-MHJ-T2 S-8357G50MC-MJJ-T2

Output voltage (V) S-8358BxxMC Series S-8358GxxMC Series

3.3 S-8358B33MC-NQS-T2

5.0 S-8358B50MC-NRJ-T2 S-8358G50MC-MNJ-T2

Please consult our sales person for products with an output voltage other than specified above.



! Pin Assignment

Figure 2 Pin Assignment

Without shutdown function, VDD/VOUT non-separate typeProducts: S-8357/58 Series B, H, F TypePackages: SOT-23-3Pin No. Pin Name Functions

1 VOUT Output voltage pin and IC power supply pin2 VSS GND pin3 EXT External transistor connection pin

Without shutdown function, VDD/VOUT non-separate typeProducts: S-8357/58 Series B, H, F TypePackages: SOT-89-3Pin No. Pin Name Functions

1 VSS GND pin2 VOUT Output voltage pin and IC power supply pin3 EXT External transistor connection pin

With shutdown function, VDD/VOUT non-separate typeProducts: S-8357/58 Series B, H, F TypePackages: SOT-23-5Pin No. Pin Name Functions

1 ON/OFFShutdown pin“H”: Normal operation (step-up oepration)“L”: Stop step-up (whole circuit stop)

2 VOUT Output voltage pin and IC power supply pin3 (N.C.)4 VSS GND pin5 EXT External transistor connection pin

With shutdown function, VDD/VOUT non-separate typeProducts: S-8357/58 Series B, H, F TypePackages: 6-Pin SNB(B)Pin No. Pin Name Functions

1 (N.C.)

2 ON/OFFShutdown pin“H”: Normal operation (Step-up oepration)“L”: Stop step-up (Whole circuit stop)

3 VOUT Output voltage pin and IC power supply pin4 EXT External transistor connection pin5 (N.C.)6 VSS GND pin

Without shutdown function, VDD/VOUT separate typeProducts: S-8357/58 Series E, J, G TypePackages: SOT-23-5Pin No. Pin Name Functions

1 VOUT Output voltage pin2 VDD IC power supply pin3 (N.C.)4 VSS GND pin5 EXT External transistor connection pin

Without shutdown function, VDD/VOUT separate typeProducts: S-8357/58 Series E, J, G TypePackages 6-Pin SNB(B)Pin No. Pin Name Functions

1 (N.C.)2 VOUT Output voltage pin3 VDD IC power supply pin4 EXT External transistor connection pin5 (N.C.)6 VSS GND pin

With shutdown function, VDD/VOUT separate typeProducts: S-8355/56 Series K, L, M TypePackages: SOT-23-5Pin No. Pin Name Functions

1 VOUT Output voltage pin2 VDD IC power supply pin


4 VSS GND pin5 EXT External transistor connection pin

With shutdown function, VDD/VOUT separate typeProducts: S-8355/56 Series K, L, M TypePackages: 6-Pin SNB(B)Pin No. Pin Name Functions


2 VOUT Output voltage pin3 VDD IC power supply pin4 EXT External transistor connection pin5 (N.C.)6 VSS GND pin

SOT-23-5321

5 4Top view

SOT-23-3

32

1Top view

SOT-89-3321

Top view

6-Pin SNB(B)321

6 45

Top view



! Absolute Maximum Ratings (Unless otherwise specified: Ta=25°C)

Parameter Symbol Ratings UnitVOUT pin voltage VOUT VSS−0.3 to VSS+12ON/OFF pin voltage*1 VON/OFF VSS−0.3 to VSS+12VDD pin voltage*2 VDD VSS−0.3 to VSS+12

B, H, F type VSS−0.3 to VOUT+0.3EXT pin voltage VEXT Others VSS−0.3 to VDD+0.3

V

EXT pin current IEXT ±80 mASOT-89-3 500SOT-23-5 250SOT-23-3 150Power dissipation PD

6-Pin SNB(B) 90

mW

Operating temperature Topr −40 to +85Storage temperature Tstg −40 to +125 °C

Note *1. With shutdown function *2. For VDD/VOUT separate types

Caution. Although the IC contains protection circuit against static electricity, excessive static electricity orvoltage which exceeds the limit of the protection circuit should not be applied to.



! Electrical Characteristics100kHz types (S-835xBxx, S-835xExx, S-835xKxx)

(Unless otherwise specified: Ta = 25°C)

Parameter Symbol Conditions Min. Typ. Max. Unit Testcircuit

Output voltage VOUT VOUT(S)×0.976 VOUT(S) VOUT(S)

×1.024Input voltage VIN − − 10 2Operation start voltage VST1 IOUT = 1 mA − − 0.9 VOscillation start voltage VST2 No external parts, voltage applied to VOUT − − 0.8 1Operation holdingvoltage VHLD

IOUT = 1 mA, Measured by decreasing VIN voltagegradually 0.7 − − 2

S-835xx15 to 19 − 14.0 23.4S-835xx20 to 29 − 19.7 32.9S-835xx30 to 39 − 25.9 43.2S-835xx40 to 49 − 32.6 54.4S-835xx50 to 59 − 39.8 66.4

Current consumption 1 ISS1 VOUT = VOUT(S) ×0.95

S-835xx60 to 65 − 47.3 78.9S-835xx15 to 19 − 5.6 11.1S-835xx20 to 29 − 5.8 11.5S-835xx30 to 39 − 5.9 11.8S-835xx40 to 49 − 6.1 12.1S-835xx50 to 59 − 6.3 12.5

Current consumption 2 ISS2 VOUT = VOUT(S) + 0.5

S-835xx60 to 65 − 6.4 12.8Current consumptionduring shutdown(with shutdown function)

ISSS VON/OFF = 0 V − − 0.5

µA

S-835xx15 to 19 −4.5 −8.9 −S-835xx20 to 24 −6.2 −12.3 −S-835xx25 to 29 −7.8 −15.7 −S-835xx30 to 39 −10.3 −20.7 −S-835xx40 to 49 −13.3 −26.7 −S-835xx50 to 59 −16.1 −32.3 −

IEXTH VEXT = VOUT − 0.4

S-835xx60 to 65 −18.9 −37.7 −S-835xx15 to 19 9.5 19.0 −S-835xx20 to 24 12.6 25.2 −S-835xx25 to 29 15.5 31.0 −S-835xx30 to 39 19.2 38.5 −S-835xx40 to 49 23.8 47.6 −S-835xx50 to 59 27.4 54.8 −

EXT pin output current

IEXTL VEXT = 0.4 V

S-835xx60 to 65 30.3 60.6 −

mA

1

Line regulation ∆VOUT1 VIN = VOUT(S) ×0.4 to × 0.6 − 30 60Load regulation ∆VOUT2 IOUT = 10 µA to VOUT(S) / 50 × 1.25 − 30 60 mV

Output voltagetemperature coefficient

∆ V O U T

∆ Ta • V O U T

Ta = − 40°C to + 85°C − ±50 − ppm/°C2

Oscillation frequency fOSC VOUT = VOUT(S) × 0.95 85 100 115 kHzMax. duty ratio MaxDuty VOUT = VOUT(S) × 0.95 75 83 90PWM/PFM switchingduty ratio (S-8356/58) PFMDuty VIN = VOUT(S) − 0.1 V, no load 10 15 24 %

VSH Measured the oscillation at EXT pin 0.75 − −VSL1 When VOUT ≥1.5 V − − 0.3

Shutdown pin inputvoltage (for shutdownfunction built-in type) VSL2

Judged the stop ofoscillation at EXT pin When VOUT<1.5 V − − 0.2

V

ISH Shutdown pin = VOUT(S) × 0.95 −0.1 − 0.1Shutdown pin inputcurrent (for shutdownfunction built-in type) ISL Shutdown pin = 0 V −0.1 − 0.1

µA

1

Soft start time tSS 3.0 6.0 12.0 msEfficiency EFFI − 86 − % 2

External parts

- Coil : CDRH6D28-470 of Sumida Corporation- Diode : RB461F(Schottky type) of Rohm Co., Ltd.- Capacitor : F93(16 V, 47 µF tantalum type) of Nichicon Corporation- Transistor : CPH3210 of Sanyo Electric Co., Ltd.- Base resister (Rb) : 1.0 kΩ- Base capacitor (Cb) : 2200 pF (ceramic type)

VIN = VOUT(S) × 0.6 applied, IOUT = VOUT(S) / 50 ΩThe shutdown function built-in type: ON/OFF pin is connected to VOUTVDD/VOUT separate type : VDD pin is connected to VOUT pin

Remark VOUT (S) specified above is the set output voltage value, and VOUT is the typical value of the output voltage.Caution VDD/VOUT separate type:

Step-up operation is performed from VDD= 0.8 V.However, 1.8≤VDD ≤10 V is recommended to stabilize the output voltage and oscillation frequency.(VDD ≥1.8 V must be applied for products with a set value of less than 1.9 V.)



250kHz types (S-835xHxx, S-835xJxx, S-835xLxx) (Unless otherwise specified: Ta = 25°C)






Current consumption 1 ISS1 VOUT = VOUT(S) × 0.95





µA





IEXTL VEXT = 0.4 V

S-835xx60 to 65 30.3 60.6 −

mA

1

Line regulation ∆VOUT1 VIN = VOUT(S) × 0.4 to × 0.6 − 30 60Load regulation ∆VOUT2 IOUT = 10 µA to VOUT(S) / 50× 1.25 − 30 60 mV


∆ V O U T

∆ Ta • V O U T

Ta = − 40°C to + 85°C − ±50 − ppm/°C2

Oscillation frequency fOSC VOUT = VOUT(S) × 0.95 212.5 250 287.5 kHzMax. duty ratio MaxDuty VOUT = VOUT(S) × 0.95 70 78 85PWM/PFM switchingduty ratio (S-8356/58) PFMDuty VIN = VOUT(S) − 0.1 V, no load 10 15 24 %



Judged the stop ofoscillation at EXT pin When VOUT <1.5 V − − 0.2

V


µA

1


External parts

- Coil : CDRH6D28-220 of Sumida Corporation- Diode : RB461F(Schottky type) of Rohm Co., Ltd.- Capacitor : F93(16 V, 47 µF tantalum type) of Nichicon Corporation- Transistor CPH3210 of Sanyo Electric Co., Ltd.- Base resister (Rb) : 1.0 kΩ- Base capacitor (Cb) : 2200 pF (ceramic type)

VIN = VOUT(S) × 0.6 applied, IOUT = VOUT(S) / 50 ΩThe shutdown function built-in type : ON/OFF pin is connected to VOUTVDD/VOUT separate type : VDD pin is connected to VOUT pin


Step-up operation is performed from VDD =0.8 V.However, 1.8≤ VDD ≤10 V is recommended to stabilize the output voltage and oscillation frequency.(VDD ≥1.8 V must be applied for products with a set value of less than 1.9 V.)



300kHz types (S-835xFxx, S-835xGxx, S-835xMxx)

(Unless otherwise specified: Ta = 25°C)






Current consumption 1 ISS1 VOUT = VOUT(S) × 0.95





µA





IEXTL VEXT = 0.4 V

S-835xx60 to 65 30.3 60.6 −

mA

1

Line regulation ∆VOUT1 VIN = VOUT(S) × 0.4 to × 0.6 − 30 60Load regulation ∆VOUT2 IOUT = 10 µA to VOUT(S) / 50 × 1.25 − 30 60 mV


∆ V O U T

∆ Ta • V O U T

Ta = − 40°C to + 85°C − ±50 − ppm/°C2

Oscillation frequency fOSC VOUT = VOUT(S) × 0.95 255 300 345 kHzMax. duty ratio MaxDuty VOUT = VOUT(S) × 0.95 70 78 85PWM/PFM switchingduty ratio (S-8356/58) PFMDuty VIN = VOUT(S) − 0.1 V, no load 10 15 24 %



Judged the stop ofoscillation at EXT pin When VOUT<1.5 V − − 0.2

V


µA

1


External parts

- Coil : CDRH6D28-220 of Sumida Corporation- Diode : RB461F(Schottky type) of Rohm Co., Ltd.- Capacitor : F93(16 V, 47 µF tantalum type) of Nichicon Corporation- Transistor : CPH3210 of Sanyo Electric Co., Ltd.- Base resister (Rb) : 1.0 kΩ- Base capacitor (Cb) : 2200 pF (ceramic type)

VIN = VOUT(S) × 0.6 applied, IOUT = VOUT(S) / 50 ΩThe shutdown function built-in type: ON/OFF pin is connected to VOUTVDD/VOUT separate type : VDD pin is connected to VOUT pin


Step-up operation is performed from VDD = 0.8 V. However, 1.8≤VDD ≤10 V is recommended to stabilize the output voltage and oscillation frequency. (VDD ≥1.8 V must be applied for products with a set value of less than 1.9 V.)



! Test Circuits

! Operation

1. Step-up DC/DC Converter

The S-8355/57 Series is a DC/DC converter using a pulse width modulation method (PWM) and

features a low current consumption.

In conventional PFM DC/DC converters, pulses are skipped at low output load current, causing

fluctuation in ripple frequency of the output voltage, with the result of increase in ripple voltage.

In S-8355/57 Series, the switching frequency does not change, although the pulse width changes from

0 % to 83 % (78 % for F, G, H, J, L, and M type) corresponding to each load current. The ripple voltage

generated from switching can thus be removed easily through the filter because the switching frequency is

constant.

S-8356/58 Series is a DC/DC converter that atuomatically switches a pulse width modulation method

(PWM) and a pulse frequency modulation method (PFM), dependeing on the load current and features a

low current consumption. Especially, the series is a highly efficient DC/DC converter at an output current of

around 100 µA.

2.

0.1µF

V-

+

-

+

(VDD)

VSS

VOUT

(ON/OFF)

EXT

Rb

Cb

Figure 3 Test Circuits 1,2

1.

VSS

VOUT

(VDD)

EXT

(ON/OFF)Oscilloscope

0.1µF -

+

A



In conventional constant-duty PFM DC/DC converters, pulses are skipped at low output load current,

causing fluctuation in ripple frequency of the output voltage, with the result of increase in ripple voltage.

The S-8356/58 Series operates under the PWM control with the pulse width duty changing from 15 % to 83

% (78 % for F, G, H, J, L, and M Series) at high output load current.

On the other hand, the S-8356/58 Series operates under the PFM control with the pulse width duty fixed

at 15 % at low output load current, and pulses are skipped at low output load current according to the load

current and output to the switching transister. The oscillation circuit thus oscillates intermittently so that the

resultant lower self-consumption could prevent the efficiency from reducing at low load current. A

switching point from the PWM control to the PFM control depends on the external devices (coil, diode,

etc.), input voltage and output voltage.

For this IC, the built-in soft start circuit controls a rush current and overshoot of the output voltage when

powering on or the ON/OFF pin is turned to “H” level.

Shutdown pin: Stops or starts step-up operation.

(Only for SOT-23-5 package products of B, H, F, K, L and M type and for 6-pin SNB(B) package

products.)

Turning the shutdown pin to “L” level stops operation of all the internal circuits and reduces the

current consumption significantly.

DO NOT use the shutdown pin in floating state because it has a structure shown in Figure 4

and

is not pulled up or pulled down internally. DO NOT apply voltage of between 0.3 V and 0.75 V to

the shutdown pin because applying such voltage increases the current consumption. If the

shutdown pin is not used, connect it to VOUT (VDD for K, L and M type) pin.

The shutdown pin doesn’t have hysteresis.

Shutdownpin

CR oscillation circuit Output voltage

“H” Operation Fixed

“L” Stop ≅ VIN*

* Voltage obtained by extracting the voltage drop due

to DC resistance of the inductor and the diode

forward voltage from VIN.

Figure 4 Shutdown pin structure

VSS

VOUT (VDD for K, L and M types)

ON/OFF



Figure 5 Step-up switching regulator circuit for basic equations

CLM1

D

VOUT

CONTVIN

L

+

-EXT

VSS

The following are basic equations [(1) through (7)] of the step-up switching regulator (see Figure 5.)Voltage at CONT pin at the moment M1 is turned ON (current IL flowing through L is zero), VA:

The change in IL over time:

Integration of the above equation :

IL flows while M1 is ON (tON). The time of tON is determined by the oscillation frequency of the OSC.

The peak current (IPK) after tON:

The energy stored in L is represented with 1/2 • L (IPK)2 .

When M1 is turned OFF (tOFF), the energy stored in L is transmitted through a diode to the output capacitor.

Then, reverse voltage (VL) is generated:

The voltage at CONT pin rises only by VOUT+VD.

The change in the current (IL) flowing through the diode into VOUT during tOFF:

= = ........................................................... (2)

IL= ............................................................................ (3)

IPK= • ton ................................................................... (4)

= = ...................................................... (6)

....................................................................... (5)

........................................................................................... (1)

(VS : Non-saturated voltage of M1)

VA=VS

dILdt

VL

LVIN−VS

L

VIN−VS

L

VIN−VS

L

dILdt

VL

L

VOUT+VD−VIN

L

VL= (VOUT+VD) − VIN

(VD : Diode forward voltage)



Integration of the above equation is as follows:

During tON, the energy is stored in L and is not transmitted to VOUT. When receiving output current (IOUT)

from VOUT, the energy of the capacitor (CL) is consumed. As a result, the pin voltage of CL is reduced, and

goes to the lowest level after M1 is turned ON (tON). When M1 is turned OFF, the energy stored in L is

ransmitted through the diode to CL, and the voltage of CL rises drastically. VOUT is a time function indicates

the maximum value (ripple voltage: VP−P) when the current flowing through into VOUT and load current (IOUT)

match.

Next, the ripple voltage is found out as follows:

IOUT vs t1 (time) from when M1 is turned OFF (after tON) to when VOUT reaches the maximum level:

When M1 is turned ON (after tOFF), IL=0 (when the energy of the inductor is completely transmitted):

Based on equation (7),

When substituting equation (10) for equation (9),

Electric charge ∆Q1 which is charged in CL during t1 :

When substituting equation (12) for equation (9):

A rise in voltage (VP−P) due to ∆Q 1:

= .........................................................(10)

t1= tOFF − • tOFF .................................................................. (11)

∆Q1= IPK − (IPK − IOUT) • t1 = • t1 .......................... (13)

IOUT = IPK− • t1 ................................................ (8)

∴ t1= (IPK−IOUT) • .............................................. (9)

IL= IPK− • t ......................................................(7)

VP-P= = • • t1 .................................. (14)

VOUT+VD−VIN

LIPK

tOFF

IPK

IOUT

VOUT+VD−VIN

L

VOUT+VD−VIN

L

∆Q1 = ∫ ILdt = IPK • ∫ dt −............................. • ∫ tdt

= IPK • t1 − • t12 .................................... (12)VOUT+VD−VIN

L 21

t10

VOUT+VD−VIN

L0t1

0t1

L

VOUT+VD−VIN

21

2IPK+IOUT

CL

∆Q1

CL

12

IPK+IOUT



VP-P= • + • RESR ................ (16)

When taking into consideration IOUT to be consumed during t1 and ESR (Equivalent Series Resistance) of

CL, namely RESR:

When substituting equation (11) for equation (15):

Therefore to reduce the ripple voltage, it is important that the capacitor connected to the output pin has a

large capacity and a small ESR.

! External parts selection for DC/DC converter

The relationship between major characteristics of the step-up circuit and characteristics parameters of the

external parts are shown in Figure 6.

For higher efficiency?For larger output current?

Operation efficiency Stand-by efficiencyFor smaller ripple voltage?

Figure 6 Relationship between major characterstics of the step-up circuit and external parts

VP-P= = • • t1 + • RESR − ...... (15)

smaller inductance larger inductance

smaller DC resistance of inductor

larger output capacitance

With MOS FET, smallerinput capacitanceWith MOS FET, smaller ON resistance

With bipolar transistor, smaller externalresistance Rb

With bipolar transistor,larger external resistanceRb

2IPK

(IPK−IOUT)2

CL

tOFF

2IPK+IOUT

larger output capacitance

CL

∆Q1

CL

12

IPK+IOUT

CL

IOUT • t12

IPK+IOUT



1. Inductor

An inductance has strong influence on maximum output current IOUT and efficiency η.

Figure 7 shows the relation between IOUT, and η characteristics to L of S-8355/56/57/58.

The peak current (IPK) increases by decreasing L and the stability of a circuit improves and IOUT increases.

If L is furthermore made small, efficiency falls and in running short, IOUT decreases. (Based on the current

drive capability of external switching transistor.)

The loss of IPK by the switching transistor decreases by increasing L and the efficiency becomes

maximum at a certain L value. Further increasing L decreases efficiency due to the loss of DC resistance

of the coil. Also, IOUT decreases, too.

Oscillation frequency is higher, smaller one can be choosed and also makes coil smaller.

The recommended inductances are 22 to 100 µH inductor for B, E,and K type, 4.7 to 47 µH inductor for

F, G, H, J, L, and M type.

Choose a value for L by refering to the reference data because the maximum output current is due to the

input voltage in an actual case. Choose an inductor so that IPK does not exceed the allowable current.

Exceeding the allowable current of the inductor causes magnetic saturation, remarkable low efficiency and

destruction of the IC chip due to a large current.

IPK in uncontinuous mode is caluculated from the following equatuon:

fosc = oscillation frequency, VD ≅ 0.4 V.

IPK =2 IOUT (VOUT+VD−VIN)

fOSC • L(A) .............................. (17)

CDRH6D28 VOUT=5.0 V, VIN=3.0 V

F, G, H, J, L, M Type

Recommended range

IOUT

η

4.7 47

Efficienccydecreases

IOUT decreases

IPK increases

Coil size:smaller

Efficienccydecreases

IOUTdecreases

IPK decreases

Coil size:bigger

L (µH)

Figure 7 L-IOUT and η characteristics



2. Diode

Use an external diode that meets the following requirements:

• Low forward voltage: (VF<0.3 V)

• High switching speed: (50 ns max.)

• Reverse voltage: VOUT + VF or more

• Rated current: IPK or more

3. Capacitor (CIN, CL)

A capacitor at the input side (CIN) improves the efficiency by reducing the power impedance and

stabilizing the input current. Select a CIN value according to the impedance of the power supply used.

A capacitor at the output side (CL) is used for smoothing the output voltage. For step-up types, the

output voltage flows intermittently to the load current so that step-up types need a larger capacitance than

step-down types. Therefore, select an appropriate capacitor depending on the ripple voltage that

increases in case of a higher output voltage or a higher load current. The capacitor value should be 10 µF

minimum.

Select an appropriate capacitor with an ESR (Equivalent Series Resistance) for stable output voltage. A

stable range of the volatge at this IC depends on the ESR. Although the inductance (L) is also a factor, an

ESR of 30 mΩ to 500 mΩ draws out the characteristics. However, the best ESR may depend on L,

capacitance, wiring and applications (output load). Therefore, fully evaluate ESRs under an actual

condition to determine the best value.

Figure 19 of Application Circuit 2 shows an example of circuit that uses a ceramic capacitor and the

external resiatance (ESR) for your reference.

4. External transistor

A bipolar (NPN) transistor or an enhancement (N-channel) MOS FET transistor can be used as external

transistor.

4.1 Bipolar (NPN) transistor

A circuit example using a bipolar transistor (NPN), Sanyo Electric Co., Ltd. CPH3210 (hFE =200 to 560)

is shown in Figure 10. The hFE value and the Rb value determine the driving capacity to increase the output

current using a bipolar transistor. A peripheral circuit example of the transistor is shown in Figure 8.

IPK

Nch

Pch

Rb

VOUT

EXT

Cb2200 pF

1 kΩ

(VDD for E, G, J, K, L, M type)

Figure 8 External transistor peripheral



1 kΩ is recommended for Rb. Rb is selected from the following caluculation. Caluculate the necessary

base current (Ib) from the bipolar transistor hFE using Ib =IPK/hFE.

A small Rb increases output current, however, the efficiency decreases. The current flows pulsating and

there is voltage drop due to wiring resistance in an actual circuit, therefore the optimum Rb value should be

determined by experiment.

A speed-up capacitor (Cb) connected in parallel with Rb resistance as shown in Figure 8 decreases the

switching loss and improves the efficiency.

Cb is caluculated from the following equatuon:

However, in practice, the optimum Cb value also varies with the characteristics of the bipolar transistor to

be employed. Therefore, determine the optimum value through experiments.

4.2 Enhancement MOS FET type

Figure 9 is a circuit example using Sanyo Electric Co., Ltd.

MPH3401 MOS FET transistor (N-channel).

For a MOS FET, an N-channel power MOS FET should be

used. Because the gate voltage and current of the external

power MOS FET are supplied from the stepped up output

voltage VOUT, the MOS FET is driven more effectively.

Depending on the MOS FET you use in your device, there

is a chance of a current overrun at power ON. Thoroughly

test all settings with your device before deciding on which

one to use. Also, try to use a MOS FET with the input

capacitance of 700 pF or less.

Since the ON resistor of the MOS FET might depend on the difference between the output voltage VOUT

and the threshold voltage of MOS FET, and affect the output current as well as the efficiency, the threshold

voltage should be low. When the output voltage is low, the circuit operates only when the MOS FET has

the threshold voltage lower than the output voltage.

Figure 9 Circuit example using MOS FET

2π • Rb • fOSC • 0.71

Cb≤

VOUT

EXT

VOUT

(ON / OFF)

VSS

(VDD)

-

+-

+

for E,G,J,K,L,and M types)( Rb= VDD−0.7Ib | IEXTH |

0.4Rb= | IEXTH |

0.4Ib

VOUT−0.7



5. VDD/VOUT separate types (E,G,J,K,L,and M type)

The E, G, J, K, L, and M type are applicable to the following applications because the power pin for the IC

chip and the VOUT pin for the output voltage are separated:

(1) When changing the output voltage with an external resistance.

(2) When outputting the high voltage such as +15 V or +20 V.

Choose the products in the following table according to applications for (1) to (2) above.

Output voltage VCC 1.8 V≤VCC<5 V 5 V≤VCC Reference circuit

S-835xx18 Yes Yes Application circuit 1 (Figure 17)S-835xx50 Yes Application circuit 1 (Figure 17)

Connection to VDD pin VIN or VCC VIN

The operational precautions are follows:

1) This IC starts to step-up operation at VDD=0.8 V but set 1.8≤VDD≤10 V to stabilize the output voltage

and frequency of the oscillator.

(Input the voltage of 1.8 V or more for VDD pin for all the products of setting less than 1.9 V)

The input voltage of 1.8 V or more for VDD pin allows the connection of the VDD pin to either input

power pin VIN or output power pin VOUT.

2) Choose external resistors RA and RB not to affect to the output voltage with the consideration of the

impedance between the VOUT and VSS pins in the IC chip.

Internal resistance between the VOUT and VSS pins are as follows:

(1) S-835xx18→5.6 MΩ to 14.9 MΩ

(2) S-835xx20→5.2 MΩ to 12.3 MΩ

(3) S-835xx50→3.8 MΩ to 10.4 MΩ

3) Attach the capacitor (CC) in parallel to RA resistance when unstable action such as the oscillation of

the output voltage occurs. Calculate CC from the following equatuon:

2 • π • RA • 20kHz

1CC(F) =



(1) S-8357BxxMA, S-8357BxxUAS-8358BxxMA, S-8358BxxUA

(2) S-8357BxxMC, S-8357FxxMC/BD, S-8357HxxMC/BDS-8358BxxMC, S-8358FxxMC/BD, S-8358HxxMC/BD

! Standard Circuits

SD

CL

VIN

L

1 kΩ

VOUT

VSS

EXT

-

+-

+

-

+PWM or PWM/PFM switchingcontrol circuit

Soft start built-in reference power supply

Phasecompensatingcircuit

Oscillation circuit

IC internal powersupply

2200 pF

CIN

Remark. The power supply for IC

chip is from VOUT pin.

Figure 10 Standard circuit (1)


Remark. The power supply for

IC chip is from VOUT pin.

-

+-

+

SD

1 kΩ

VIN

LVOUT

VSS

EXT

-

+

2200 pF

CIN

ON/OFF

CL

PWM or PWM/PFM switchingcontrol circuit



Oscillation circuit

IC internal powersupply

(3) S-8357ExxMC, S-8357GxxMC/BD, S-8357JxxMC/BDS-8358ExxMC, S-8358GxxMC/BD, S-8358JxxMC/BD

Remark. The power supply

for IC chip is from VDD pin.


-

+-

+

-

+

CL

L

SD

1 kΩ

VIN

VOUT

VSS

EXT

2200 pF

CIN

VDD




Oscillation circuit IC internalpowersupply



(4) S-8357EXXMC, S-8357GXXMC/BD, S-8357JXXMC/BDS-8358EXXMC, S-8358GXXMC/BD, S-8358JXXMC/BD

(5) S-8355KXXMC, S-8355LXXMC/BD, S-8355MXXMC/BDS-8356KXXMC, S-8356LXXMC/BD, S-8356MXXMC/BD

-

+

-

+

-

+

CL

ON/OFF

L

SD

1 kΩ

VIN

VOUT

VSS

EXT

2200 pF

CIN

VDD





Remark.The power supply

for IC chip


(6) S-8355KXXMC, S-8355LXXMC/BD, S-8355MXXMC/BDS-8356KXXMC, S-8356LXXMC/BD, S-8356MXXMC/BD

-

+

-

+

CL

ON/OFF

L

SD

1 kΩ

VIN

VOUT

VSS

EXT

2200 pF

CIN

VDD

-





Remark.The power supply

for IC chip


Remark. The power supply

for IC chip is from VDD pin.


SD

1 kΩ

VIN

VOUT

VSS

EXT

2200 pF

CIN

VDD

-

+

-

+

CL

L

-







! Power Dissipation of Package

! Precautions

• Mount external capacitors, a diode, and a coil as close as possible to the IC.

• Unique ripple voltage and spike noise occur in switching regulators. Because they largely depend on the

coil and the capacitor used, check them using an actually mounted model.

• Make sure dissipation of the switching transistor (especially at a high temperature) does not exceed the

allowable power dissipation of the package.

• The performance of this IC varies depending on the design of the PCB patterns, peripheral circuits and

external parts. Thoroughly test all settings with your device. Also, try to use recommended external parts.

If not, contact your SII sales person.

• Seiko Instruments Inc. shall not be responsible for any patent infringement by products including S-

8355/56/57/58 Series in connection with the method of using S-8355/56/57/58 Series in such products,

the specification of such products, or the country of destination thereof.

Figure 16 Power dissipation of the package (before mounting)

0 50 100 150

600

400

200

0

PowerDissipation

PD

(mW)

Ambient Temperature Ta (°C)

SOT-23-3

SOT-89-3

6-Pin SNB(B)

SOT-23-5



! Application Ciruits

1. LCD Power Supply

The following examples are an application power supply circuit (15 V/20 V output) to drive LCD panels, and

its characteristics.

Outputvoltage IC L type name TR type name SD type name CL Ra Rb Cc Output

characteristics

(1) 15 V S-8356M50 CDRH5D18-220 MCH3405 MA2Z748 F93(20 V,10 µF) 580 kΩ 300 kΩ 15 pF (1-a),(1-b)(2) 20 V S-8356M50 CDRH5D18-220 FDN337N MA729 F93(25 V,10 µF) 575 kΩ 200 kΩ 15 pF (2-a),(2-b)

12

13

14

15

16

0.01 0.1 1 10 100

VIN=3 VVIN=5 VVIN=7 V

14

16

18

20

22

0.01 0.1 1 10 100


Output Current IOUT [mA]

(2-b) Output Current vs. Output Voltage

Out

put V

olta

ge V

OU

T [V

]



Out

put V

olta

ge V

OU

T [V

]

0

20

40

60

80

100

0.01 0.1 1 10 100


0

20

40

60

80

100

0.01 0.1 1 10 100



(2-a) Output Current vs. Efficiency

Effic

ienc

y η

[%]



Effic

ienc

y η

[%]

Figure 18 LCD power supply output characteristics

Figure 17 Power supply circuit for LCD

S-8356M50

EXT

VOUT

VSS

VDD

ON/OFF

VOUT

SD

CLCC

L

RB

RA

TR

CINVIN

-

++

-



2. Ceramic CapacitorIf using small ESR parts such as ceramic capacitors to the output capacitance, attach a resistor (R1)

corresponding to the ESR in series to the ceramic capacitor (CL) as shown in the following circuit.

R1 may depend on L, capacitance, wiring and applications (output load).

The follwong examples are a circuit using R1 =100 mΩ, output voltage =3.3 V, output load =500 mA and its

characteristics.

IC L type name TR type name SD type name CL

(ceramic capacitor) R1 Output characteristics

(1) S-8357F33 CDRH6D28-220 FDN335N M1FH3 10 µF×2 pieces 100 mΩ (1-a),(1-b),(1-c)(2) S-8358B50 CDRH6D28-470 FDN335N M1FH3 10 µF×2 pieces 100 mΩ (2-a),(2-b),(2-c)

EXT VOUT

VSS

VOUTSD

CL

L

R1TR

VIN CIN

Figure 19 Circuit using ceramic capacitor



0

20

40

60

80

100

120

0.01 0.1 1 10 100 1000

VIN=0.9 VVIN=1.8 VVIN=2.7 V

0

20

40

60

80

100

120

0.01 0.1 1 10 100 1000


3.28

3.29

3.30

3.31

3.32

0.01 0.1 1 10 100 1000


5.03

5.04

5.05

5.06

5.07

0.01 0.1 1 10 100 1000


0

20

40

60

80

100

0.01 0.1 1 10 100 1000


0

20

40

60

80

100

0.01 0.1 1 10 100 1000



(2-a) Output Current vs. EfficiencyEf

ficie

ncy

η [%

]



Effic

ienc

y η

[%]



Out

put V

olta

ge V

OU

T [V

]



Out

put V

olta

ge V

OU

T [V

]


(2-c) Output Current vs. Ripple Voltage

Rip

ple

Volta

ge

Vr [m

V]

(1-c) Output Current vs. Ripple Voltage


Rip

ple

Volta

ge

Vr [m

V]

Figure 20 Ceramic capacitor circuit output characteristics



! Example of Major Temperature Characteristics (Ta = −40 to 85°C)

ISS1 vs. Ta (VOUT=3.3 V, fosc=100 kHz)

0

10

20

30

40

50

-40 -20 0 20 40 60 80 100Ta [°C]

ISS1[µA]

ISS1 vs. Ta (VOUT=3.3V, fosc=300 kHz)

0

10

20

30

40

50

-40 -20 0 20 40 60 80 100Ta [°C]

ISS1[µA]


0

2

4

6

8

10

-40 -20 0 20 40 60 80 100Ta [°C]

ISS2[µA]


0

2

4

6

8

10

-40 -20 0 20 40 60 80 100Ta [°C]

ISS2[µA]

ISSS vs. Ta (VOUT=3.3 V, fosc=100 kHz)

0.0

0.2

0.4

0.6

0.8

1.0

-40 -20 0 20 40 60 80 100Ta [°C]

ISSS[µA]

ISSS vs. Ta (VOUT=3.3 V, fosc=300kHz)

0.0

0.2

0.4

0.6

0.8

1.0

-40 -20 0 20 40 60 80 100Ta [°C]

ISSS[µA]

IEXTH vs. Ta (VOUT=3.3 V, fosc=300 kHz)

-

-10

-20

-30

-40

-50

-60

-40 -20 0 20 40 60 80 100Ta [°C]

IEXTH[mA]

0

IEXTL vs. Ta (VOUT=3.3 V, fosc=300 kHz)

0

10

20

30

40

50

60

-40 -20 0 20 40 60 80 100Ta [°C]

IEXTL[mA]



FOSC vs. Ta (VOUT=3.3 V, fosc=100 kHz)

50

75

100

125

150

-40 -20 0 20 40 60 80 100Ta [°C]

fOSC[kHz]

FOSC vs. Ta (VOUT=3.3 V, fOSC =300 kHz)

200

250

300

350

400

-40 -20 0 20 40 60 80 100Ta [°C]

fOSC[kHz]

MaxDuty vs. Ta (VOUT=3.3 V, fosc=100 kHz)

70

75

80

85

90

-40 -20 0 20 40 60 80 100Ta [°C]

MaxDuty[%]

MaxDuty vs. Ta (VOUT=3.3 V, fosc=300 kHz)

70

75

80

85

90

-40 -20 0 20 40 60 80 100Ta [°C]

MaxDuty[%]

VSH vs. Ta (VOUT=3.3 V, fosc=300 kHz)

0.0

0.2

0.4

0.6

0.8

1.0

-40 -20 0 20 40 60 80 100Ta [°C]

VSH[V]

VSL1 vs. Ta (VOUT=3.3 V, fosc=300 kHz)

0.0

0.2

0.4

0.6

0.8

1.0

-40 -20 0 20 40 60 80 100Ta [°C]

VSL1[V]

VSL2 vs. Ta (VOUT=3.3 V, fosc=300 kHz)

0.0

0.2

0.4

0.6

0.8

1.0

-40 -20 0 20 40 60 80 100Ta [°C]

VSL2[V]

PFMDuty vs. Ta (VOUT=3.3 V, fosc=100 kHz)S-8356/58 Series

5

10

15

20

25

-40 -20 0 20 40 60 80 100Ta [°C]

PFMDuty[%]



TSS−Ta (VOUT=3.3 V, fosc=100 kHz)

0

2

4

6

8

-40 -20 0 20 40 60 80 100Ta [°C]

TSS[ms]

VST1−Ta (VOUT=3.3 V, fosc=100 kHz)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

-40 -20 0 20 40 60 80 100Ta [°C]

VST1[V]

TSS−Ta (VOUT=3.3 V, fosc=300 kHz)

0

2

4

6

8

-40 -20 0 20 40 60 80 100Ta [°C]

TSS[ms]

VST2−Ta (VOUT=3.3 V, fosc=300 kHz)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

-40 -20 0 20 40 60 80 100Ta [°C]

VST2[V]

VOUT−Ta (VOUT=3.3 V, fosc=100 kHz)

3.20

3.25

3.30

3.35

3.40

-40 -20 0 20 40 60 80 100Ta [°C]

VOUT[V]

VOUT−Ta (VOUT=3.3 V, fosc=300 kHz)

3.20

3.25

3.30

3.35

3.40

-40 -20 0 20 40 60 80 100Ta [°C]

VOUT[V]



! Example of Major Power Supply Dependence Characteristics (Ta=25°C)

ISS1,2 vs. VDD

(VOUT =3.3 V, Fosc =300 kHz, Ta =25°C)

0

10

20

30

40

50

0 2 4 6 8 10VDD[V]

ISS1,2[µA]

ISSS vs. VDD

(VOUT =3.3 v, fosc =300 kHz, Ta =25°C)

0.0

0.2

0.4

0.6

0.8

1.0

0 2 4 6 8 10VDD[V]

ISSS[µA]

IEXTH vs. VDD

-

-20

-40

-60

-80

-100

0 2 4 6 8 10VDD[V]

IEXTH[mA]

0

IEXTL vs. VDD

0

20

40

60

80

100

0 2 4 6 8 10VDD[V]

IEXTL[mA]

fOSC vs. VDD (fOSC =300 kHz)

60

120

180

240

300

360

0 2 4 6 8 10VDD[V]

fOSC

[kHz]

fOSC vs. VDD (fOSC =100 kHz)

20

40

60

80

100

120

0 2 4 6 8 10VDD[V]

fOSC

[kHz]

1.5

2.0

2.5

3.0

3.5

0 2 4 6 8 10VDD[V]

V OUT[V]

1.5

2.0

2.5

3.0

3.5

0 2 4 6 8 10VDD[V]

VOUT[V]

VOUT vs. VDD(VOUT=3.3 V, fOSC=100 kHz, VDD separate type)

VIN=1.98 V, IOUT=66 mA

VOUT vs. VDD(VOUT=3.3 V, fOSC=300 kHz, VDD separate type)

VIN=1.98 V, IOUT=66 mA



! Output Waveforms1. S-8358B33MC

1. IOUT=1 mA

-25 -20 -15 -10 -5 0 5 10 15 20 25time [µs]

4

2

0

3.40

3.35

3.30

3.25

2. IOUT=20 mA

-25 -20 -15 -10 -5 0 5 10 15 20 25time [µs]

4

2

0

3.40

3.35

3.30

3.25

3. IOUT=100 mA

-25 -20 -15 -10 -5 0 5 10 15 20 25time [µs]

4

2

0

3.40

3.35

3.30

3.25

4. IOUT=200 mA

-25 -20 -15 -10 -5 0 5 10 15 20 25time [µs]

4

2

0

3.40

3.35

3.30

3.25

2. S-8358F33MC

4. IOUT =200 mA

-10 -8 -6 -4 -2 0 2 4 6 8 10time [µs]

4

2

0

3.40

3.35

3.30

3.25

1. IOUT =1 mA

-10 -8 -6 -4 -2 0 2 4 6 8 10time [µs]

4

2

0

3.40

3.35

3.30

3.25

3. IOUT =100 mA

-10 -8 -6 -4 -2 0 2 4 6 8 10time [µs]

4

2

0

3.40

3.35

3.30

3.25

2. IOUT =10 mA

-10 -8 -6 -4 -2 0 2 4 6 8 10time [µs]

4

2

0

3.40

3.35

3.30

3.25

OutputVoltage

[0.05 V/div]

CONTVoltage[2 V/div]

OutputVoltage

[0.05 V/div]


OutputVoltage

[0.05 V/div]


OutputVoltage

[0.05 V/div]


OutputVoltage

[0.05 V/div]


OutputVoltage

[0.05 V/div]


OutputVoltage

[0.05 V/div]


OutputVoltage

[0.05 V/div]




! Examples of Transient Response characteristics1. Powering ON (VIN ;0 V→2.0 V )

0

2

-1 0 1 2 3 4 5 6 7 8 9time [ms]

VIN

[V]

0

2

4VOUT

[V]

0

2

-1 0 1 2 3 4 5 6 7 8 9time [ms]

VIN

[V]

0

2

4VOUT

[V]

0

2

-1 0 1 2 3 4 5 6 7 8 9time [ms]

VIN

[V]

0

2

4VOUT

[V]

0

2

-1 0 1 2 3 4 5 6 7 8 9time [ms]

VIN

[V]

0

2

4VOUT

[V]

2. Responses of Shutdown pin (ON/OFF ;0 V→2.0 V )

V ON/OFF (100 kHz, IOUT=1 mA)

0

2

-1 0 1 2 3 4 5 6 7 8 9time [ms]

VON/OFF[V]

0

2

4VOUT

[V]

ON/OFF (100 kHz, IOUT=100 mA)

0

2

-1 0 1 2 3 4 5 6 7 8 9time [ms]

VON/OFF[V]

0

2

4VOUT

[V]


0

2

-1 0 1 2 3 4 5 6 7 8 9time [ms]

VON/OFF[V]

0

2

4VOUT

[V]


0

2

-1 0 1 2 3 4 5 6 7 8 9time [ms]

VON/OFF[V]

0

2

4VOUT

[V]

Powering ON (100 kHz, IOUT=1 mA )






3. Load Fluctuations

-0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8time [ms]

3.00

3.20

3.40

3.60

VOUT[0.2 V/div]

100 µA

IOUT

100 mA

-10 0 10 20 30 40 50 60 70 80 90time [ms]

3.20

3.40

3.60

3.80

VOUT

[0.2 V/div]

100 µA

IOUT

100 mA

-0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5time [ms]

3.00

3.20

3.40

3.60

VOUT

[0.2 V/div]

100 µA

IOUT

100 mA

-10 0 10 20 30 40 50 60 70 80 90time [ms]

3.20

3.40

3.60

3.80

VOUT

[0.2 V/div]

100 µA

IOUT

100 mA

4. Power Voltage Fluctuations

=100mA)V

=100mA)V

1.5

2.0

2.5

3.0

-0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8time [ms]

3.25

3.30

3.35

3.40

3.45

VIN [V]VOUT

[V]

1.5

2.0

2.5

3.0

-0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8time [ms]

3.25

3.30

3.35

3.40

3.45

VIN [V]VOUT

[V]

1.5

2.0

2.5

3.0

-0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8time [ms]

3.25

3.30

3.35

3.40

3.45

VIN [V]

[V]

1.5

2.0

2.5

3.0

-0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8time [ms]

3.25

3.30

3.35

3.40

3.45

VIN [V] VOUT

[V]VOUT

Power Voltage Fluctuation (100 kHz, IOUT=100 mA)

VIN=1.98 V→2.64 V

Load Fluctuation (100 kHz, IOUT; 100 µA→100 mA)

Load Fluctuation (300 kHz, IOUT; 100 µ A→100 mA)

Load Fluctuation (100 kHz, IOUT; 100 mA→100 µA)

Load Fluctuation (300 kHz, IOUT; 100 mA→100 µA)


VIN=2.64→1.98 V


VIN=1.98 V→2.64 V


VIN=2.64 V→1.98 V



! Reference DataUse reference data to choose the external parts. The reference data here give you the procedure to choose

the recommended external parts for various applications and its characteristics data.

1. Reference Data for External Components

Table 1. Efficiency vs. Output characteristics and Output Voltage vs. Output Current characteristicsfor external components

No. Productname

Oscillationfrequency

Outputvoltage

Controlsystem Inductor Transister Diode Output capacitor

(1) S-8357F33 300 kHz 3.3 V PWM CDRH104R-220 FDN335N M1FH3 F93(16 V,47 µF)×2(2) S-8357F50 300 kHz 5.0 V PWM ↑ ↑ ↑ ↑(3) S-8356M50 300 kHz 5.0 V PWM/PFM ↑ ↑ ↑ ↑(4) S-8357B33 100 kHz 3.3 V PWM CDRH104R-470 ↑ ↑ ↑(5) S-8358B33 100 kHz 3.3 V PWM/PFM ↑ ↑ ↑ ↑(6) S-8357B50 100 kHz 5.0 V PWM ↑ ↑ ↑ ↑(7) S-8356M50 300 kHz 5.0 V PWM/PFM CDRH8D28-220 FDN335N M1FH3 F93(16 V,47 µF)(8) S-8357B33 100 kHz 3.3 V PWM CDRH8D28-470 ↑ ↑ ↑(9) S-8358B33 100 kHz 3.3 V PWM/PFM ↑ ↑ ↑ ↑

(10) S-8357B50 100 kHz 5.0 V PWM ↑ ↑ ↑ ↑(11) S-8357F33 300 kHz 3.3 V PWM CDLP120-220 MCH3405 MA2Z748 F92(6.3 V,47 µF)(12) S-8356M50 300 kHz 5.0 V PWM/PFM ↑ ↑ ↑ ↑

The properties of external parts are shown below.

Table 2. Properties of external parts

Part Product name Manufacturer CharacteristicsInductor CDRH104R-220 Sumida Corporation 22 µH, DCR*1 =93 mΩ, Imax*2 =2.9 A, Height =4.0 mm

CDRH104R-470 47 µH, DCR*1 =128 mΩ, Imax*2 =2.1 A, Height =4.0 mmCDRH8D28-220 22 µH, DCR1) =95 mΩ, Imax*2 =1.6 A, Height =3.0 mmCDRH8D28-470 47 µH, DCR*1 =190 mΩ, Imax*2 =1.15 A, Height =3.0 mm

CXLP120-220 Sumitomo SpecialMetals Co., Ltd. 22 µH, DCR*1 =590 mΩ, Imax*2 =0.55 A, Height =1.0 mm

Diode M1FH3 Shindengen ElectricManufacturing Co., Ltd. VF

*3 =0.3V, IF*4 =1.5 A

MA2Z748 Matsushita ElectricIndustrial Co., Ltd. VF

*3 =0.4V, IF*4 =0.3 A

F93 Nichicon Corporation 16 V, 47 µFCapacitor(Output capacitance) F92 6.3 V, 47 µFTransister(Nch FET) FDN335N Fairchild Semiconductor

Japan Ltd.Vdss*5 =20 Vmax, Vgss*6 =8 Vmax, Ciss*7 =310 pF,Id*8 =1.5 A (Vgs*9 =2.5 V)

MCH3405 Sanyo Electric Co., Ltd. Vdss*5 =20 Vmax, Vgss*6 =10 Vmax, Ciss*7 =280 pF,Id*8 =0.5 A (Vgs*9 =1.8 V)

*1. DC resistance, *2. Maximum allowable current, *3. Forward voltage, *4. Forward current, *5. Drain-source voltage,*6. Gate-source voltage, *7. Input capacitance, *8. Drain current, *9 Gate-source voltage

Caution. The values shown in the characteristics column of Table 2 above are based on the materials provided by eachmanufacturer, however, consider the characteristics of the original materials when using the above products.



2. Reference Data 1

The data of (a) Output current vs. efficiency characteristics and (b) Output current vs. output voltage

characteristics under conditions of (1) to (12) shown in Table 1 are shown below.

(1) S-8357F33

3.0

3.1

3.2

3.3

3.4

3.5

0.1 1 10 100 1000

VIN=0.9 V VIN=1.8 V VIN=2.7 V

20

40

60

80

100


0.1 1 10 100 1000Output Current IOUT [mA]

(b) Output Current vs. Output Voltage

Effic

ienc

y η

[%]

(a) Output Current vs. Efficiency

Output Current IOUT [mA]O

utpu

t Vol

tage

VO

UT

[V]

(2) S-8357F50

4.7

4.8

4.9

5.0

5.1

5.2

0.1 1 10 100 1000

VIN=2 V VIN=3 V VIN=4 V

20

40

60

80

100

1 10 100 1000


0.1Output Current IOUT [mA]


Effic

ienc

y η

[%]



Out

put V

olta

ge V

OU

T [V

]

(3) S-8356M50

20

40

60

80

100

0.1 1 10 100 1000


4.7

4.8

4.9

5.0

5.1

5.2

0.1 1 10 100 1000




Effic

ienc

y η

[%]



Out

put V

olta

ge V

OU

T [V

]



(4) S-8357B33

20

40

60

80

100

0.1 1 10 100 1000


3.0

3.1

3.2

3.3

3.4

3.5

0.1 1 10 100 1000




Effic

ienc

y η

[%]



Out

put V

olta

ge V

OU

T [V

]

(5) S-8358B33

20

40

60

80

100

0.1 1 10 100 1000


3.0

3.1

3.2

3.3

3.4

3.5

0.1 1 10 100 1000




Effic

ienc

y η

[%]



Out

put V

olta

ge V

OU

T [V

]

(6) S-8357B50

20

40

60

80

100

0.1 1 10 100 1000


4.7

4.8

4.9

5.0

5.1

5.2

0.1 1 10 100 1000




Effic

ienc

y η

[%]



Out

put V

olta

ge V

OU

T [V

]



(7) S-8356M50

20

40

60

80

100

0.1 1 10 100 1000


4.7

4.8

4.9

5.0

5.1

5.2

0.1 1 10 100 1000




Effic

ienc

y η

[%]



Out

put V

olta

ge V

OU

T [V

](8) S-8357B33

0

20

40

60

80

100

0.1 1 10 100 1000

VIN=0.9V VIN=1.8V VIN=2.7V

3.0

3.1

3.2

3.3

3.4

3.5

0.1 1 10 100 1000




Effic

ienc

y η

[%]



Out

put V

olta

ge V

OU

T [V

]

(9) S-8358B33

20

40

60

80

100

0.1 1 10 100 1000


3.0

3.1

3.2

3.3

3.4

3.5

0.1 1 10 100 1000




Effic

ienc

y η

[%]



Out

put V

olta

ge V

OU

T [V

]



(10) S-8357B50

20

40

60

80

100

0.1 1 10 100 1000


4.7

4.8

4.9

5.0

5.1

5.2

0.1 1 10 100 1000



(b) Output Current vs.Output Voltage

Effic

ienc

y η

[%]



Out

put V

olta

ge V

OU

T [V

](11) S-8357F33

3.0

3.1

3.2

3.3

3.4

3.5

0.1 1 10 100 1000

IN=0.9V IN=1.8V IN=2.7V

20

40

60

80

100

0.1 1 10 100 1000

IN=0.9V IN=1.8V IN=2.7V



Effic

ienc

y η

[%]



Out

put V

olta

ge V

OU

T [V

]

(12) S-8356M50

20

40

60

80

100

0.1 1 10 100 1000


4.7

4.8

4.9

5.0

5.1

5.2

0.1 1 10 100 1000




Effic

ienc

y η

[%]



Out

put V

olta

ge V

OU

T [V

]



3. Reference Data 2

The actual output current vs. ripple voltage characteristics data under conditions of (1) to (12) in Table 1

are shown below.

(1) S-8357F33 (2) S-8357F50

0

50

100

150

0.1 1 10 100 1000


0

50

100

150

0.1 1 10 100 1000



Output Current vs. Ripple Voltage

Rip

ple

Volta

ge V

r [m

V]


Output Current IOUT [mA]R

ippl

e Vo

ltage

Vr [

mV]

(3) S-8356M50 (4) S-8357B33

0

50

100

150

0.1 1 10 100 1000


0

50

100

150

0.1 1 10 100 1000




Rip

ple

Volta

ge V

r [m

V]



Rip

ple

Volta

ge V

r [m

V]

(5) S-8358B33 (6) S-8357B50

0

50

100

150

0.1 1 10 100 1000


0

50

100

150

0.1 1 10 100 1000




Rip

ple

Volta

ge V

r [m

V]


Outｚ put Current IOUT [mA]

Rip

ple

Volta

ge V

r [m

V]



(7) S-8356M50 (8) S-8357B33

0

50

100

150

0.1 1 10 100 1000


0

50

100

150

0.1 1 10 100 1000




Rip

ple

Volta

ge V

r [m

V]



Rip

ple

Volta

ge V

r [m

V]

(9) S-8358B33 (10) S-8357B50

0

50

100

150

0.1 1 10 100 1000


0

50

100

150

0.1 1 10 100 1000




Rip

ple

Volta

ge V

r [m

V]



Rip

ple

Volta

ge V

r [m

V]

(11) S-8357F33 (12) S-8356M50

0

50

100

150

0.1 1 10 100 1000


0

50

100

150

0.1 1 10 100 1000




Rip

ple

Volta

ge V

r [m

V]



Rip

ple

Volta

ge V

r [m

V]

2.9±0.2

0.95±0.1

1.9±0.2

+0.1 -0.050.16

0.4±0.1

0.25

+0.2 -0.62.8

0∼0.1

1

2 3

1.5

1.3max.1.1±0.1

T2

1.6±0.1

0.25±0.05

4.0±0.12.0±0.1

4.0±0.1

1.5+0.1 -0.05

1.1±0.1

2.85±0.2

Feed direction

1.75±0.1

3.5±0.1

8.0±0.23.05±0.2

No.:MP003-A-C-SD-1.0

21±0.5

2±0.2

(60°)(60°)

ø13±0.2

12.5max.

9.0±0.3

Winding core

ø60+1 -0

ø180+0 -3

n SOT-23-3MP003-A 990531

No.:MP003-A-P-SD-1.0

No.:MP003-A-R-SD-1.0

Unit:mmlDimensions

lTaping Specifications lReel Specifications1 reel holds 3000 ICs.

! !

"

#

$%&'())*

+,-%()

$ %.)& !

//0!

0)),,()%

1

!

"#$"#$

%

%

&

%

%%%

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%"*'(%&$

+&

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&-

. /

&

./

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!

"

#$%&

!"

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+ ++

+

( *

,

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• The information described herein is subject to change without notice.• Seiko Instruments Inc. is not responsible for any problems caused by circuits or diagrams described herein

whose related industrial properties, patents, or other rights belong to third parties. The application circuitexamples explain typical applications of the products, and do not guarantee the success of any specificmass-production design.

• When the products described herein are regulated products subject to the Wassenaar Arrangement or otheragreements, they may not be exported without authorization from the appropriate governmental authority.

• Use of the information described herein for other purposes and/or reproduction or copying without theexpress permission of Seiko Instruments Inc. is strictly prohibited.

• The products described herein cannot be used as part of any device or equipment affecting the humanbody, such as exercise equipment, medical equipment, security systems, gas equipment, or any apparatusinstalled in airplanes and other vehicles, without prior written permission of Seiko Instruments Inc.

• Although Seiko Instruments Inc. exerts the greatest possible effort to ensure high quality and reliability, thefailure or malfunction of semiconductor products may occur. The user of these products should thereforegive thorough consideration to safety design, including redundancy, fire-prevention measures, andmalfunction prevention, to prevent any accidents, fires, or community damage that may ensue.

Documents

ULTRA-SMALL PACKAGE PWM CONTROL, PWM/PFM …56,57,58_e.pdf · Rev.1.2-12 Seiko Instruments Inc. 1 The S-8355/56/57/58 Series is a CMOS step-up switching regulator which mainly consists