1.0A USB Port/Adapter Lithium-Ion/Polymer Battery Charger - AATI/AAT3690IWP-4.2... · 1.0A USB Port/Adapter Lithium-Ion/Polymer Battery Charger 3690.2007.01.1.2 1 BatteryManager™

AAT36901.0A USB Port/Adapter

Lithium-Ion/Polymer Battery Charger

3690.2007.01.1.2 1

BatteryManager™General DescriptionThe AAT3690 BatteryManager is a highly integrat-ed single-cell lithium-ion/polymer battery chargerIC designed to operate with USB port and ACadapter inputs. It requires the minimum number ofexternal components.

The AAT3690 precisely regulates battery chargevoltage and current for 4.2V lithium-ion/polymerbattery cells. Adapter charge current rates can beprogrammed up to 1.0A. In the absence of anadapter and with a USB port connected, the bat-tery can also be charged by USB power. The USBcharge current can be programmed up to 1A. ACharge Reduction Loop is also built in to allowusers to charge the battery with the available cur-rent from a USB port, while keeping the port volt-age regulated. USB charging is disabled when anadapter is present.

Battery temperature and charge state are fullymonitored for fault conditions. In the event of anover-voltage or over-temperature condition, thedevice will automatically shut down, thus protectingthe charging device, control system, and the bat-tery under charge. Status monitor output pins areprovided to indicate the battery charge status bydirectly driving two external LEDs.

The AAT3690 is available in a Pb-free, thermally-enhanced, space-saving 12-pin 3x3mm TDFNpackage and is rated over the -40°C to +85°C tem-perature range.

Features• USB/AC Adapter System Power Charger

— USB: Programmable up to 1.0A— Adapter: Programmable up to 1.0A

• 4.0V to 5.5V Input Voltage Range• Adapter Presence Automatically Disables

USB Charging• High Level of Integration With Internal:

— Charging Devices— Reverse Blocking Diodes— Current Sensing

• Automatic Recharge Sequencing• Digital Thermal Regulation in ADP Charge• Charge Reduction Loop in USB Charge• Battery Temperature Monitoring• Full Battery Charge Auto Turn-Off• Over-Current Protection• Over-Voltage Protection• Emergency Thermal Protection• Power On Reset and Soft Start• Serial Interface Status Reporting• 12-Pin 3x3mm TDFN Package

Applications• Cellular Telephones• Digital Still Cameras• Hand-Held PCs• MP3 Players• Personal Data Assistants (PDAs)• Other Lithium-Ion/Polymer Battery-Powered

Devices

Typical Application

AAT3690

C2

10μF

BATT-

TEMP

USB Input

Battery Pack

USB

ADP

ADPSET

CT

GND

TS

BAT

BATT+

RSETADP

CT

ADP Input

STAT1

RSETUSB

USBSET

EN

STAT2

Enable

Pin Descriptions

Pin ConfigurationTDFN33-12(Top View)

USBBATADP

1

GNDENTS

ADPSETUSBSETUSBCTSTAT1STAT2

2

3

4

5

6

12

11

10

9

8

7

Pin # Name Type Function1, 10 USB In USB power supply input.

2 BAT In/Out Battery charging and sensing.3 ADP In Adapter power supply input.4 GND Ground Ground connection.5 EN In Enable pin. Logic high enables the IC. When open, this pin is internally

pulled up to the higher voltage of ADP and USB inputs.6 TS In/Out Connect to 10kΩ NTC thermistor. When TS is open, the battery tempera-

ture sensing function is disabled.7 STAT2 Out Battery charge status indicator pin to drive an LED: active low, open-drain.8 STAT1 Out Battery charge status indicator pin to drive an LED: active low, open-drain.9 CT In/Out Timing capacitor to adjust internal watchdog timer. Set maximum charge

time for adapter powered CC and CV charge modes. The watchdog timeronly sets the timers for adapter battery charging; there is no timeout for thebattery charging from the USB input. If timing function is not needed, termi-nate this pin to ground.

11 USBSET In/Out Connect a resistor between this pin and GND to set USB charging current.12 ADPSET In/Out Connect a resistor between this pin and GND to set adapter charging

current.EP Exposed paddle (bottom); connect to GND directly beneath package.



2 3690.2007.01.1.2

Absolute Maximum Ratings1

Thermal Information2

Symbol Description Value UnitsθJA Maximum Thermal Resistance 50 °C/WPD Maximum Power Dissipation 2.0 W

Symbol Description Value UnitsVP USB, ADP, <30ms, Duty Cycle <10% -0.3 to 7.0 VVP USB, ADP Continuous -0.3 to 6.0 VVN BAT, USBSEL, USBSET, ADPSET, STAT1, STAT2, TS, CT, EN -0.3 to VP + 0.3 VTJ Operating Junction Temperature Range -40 to 150 °C

TLEAD Maximum Soldering Temperature (at leads) 300 °C



3690.2007.01.1.2 3

1. Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at condi-tions other than the operating conditions specified is not implied. Only one Absolute Maximum Rating should be applied at any one time.

2. Mounted on a FR4 board.

Electrical Characteristics1

VADP = 5V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = 25°C.

Symbol Description Conditions Min Typ Max UnitsOperationUSB, ADP USB Port or Adapter Voltage Range 4.0 5.5 V

VU_DSBLADP Voltage Level to Disable

4.25 4.5 4.7 VUSB Charging

VUVLOUnder-Voltage Lockout Rising Edge 3.0 VUnder-Voltage Lockout Hysteresis 150 mV

IOP Operating Current CC Charge Current = 500mA 0.75 1.5 mAISLEEP Sleep Mode Current VBAT = 4.25V 2.0 5.0 μA

ILeakageReverse Leakage Current from VBAT = 4V, USB,

1.0 μABAT Pin ADP Pins Open

Voltage RegulationVBAT_EOC

1 End of Charge Voltage Accuracy 4.158 4.2 4.242 VΔVBAT/VBAT EOC Voltage Tolerance 0.5 %

VRCH Battery Recharge Voltage Threshold VBAT_EOC - 0.1 VVUSB_CHR USB Charge Reduction Regulation 4.3 4.5 4.64 V

Current Regulation

ICH Charge CurrentADP Input 100 1000

mAUSB Input 50 1000

ΔICH/ICH Charge Current Regulation Tolerance 10 %VADPSET ADPSET Pin Voltage In CC Mode 2.0 VVUSBSET USBSET Pin Voltage In CC Mode 2.0 V

KIADP Current Set Factor: ICHARGE/IADPSET 4000KIUSB Current Set Factor: ICHARGE/IUSBSET 2000

Charging Devices

RDS(ON)AAdapter Charging Transistor

VIN = 5.5V 0.2 0.25 0.35 ΩOn Resistance

RDS(ON)UUSB Charging Transistor

VIN = 5.5V 0.4 0.5 0.65 ΩOn Resistance



4 3690.2007.01.1.2

1. The AAT3690 output charge voltage is specified over the 0° to 70°C ambient temperature range; operation over the -40°C to +85°Ctemperature range is guaranteed by design.

Electrical Characteristics1

VADP = 5V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = 25°C.

Symbol Description Conditions Min Typ Max UnitsLogic Control / Protection

VEN(H) Input High Threshold 1.6 VVEN(L) Input Low Threshold 0.4 V

TCConstant Current Mode Time Out

CCT = 100nF, VADP = 5.5V 3.0 Hour(ADP mode only)

TVConstant Voltage Mode Time Out

CCT = 100nF, VADP = 5.5V 3.0 Hour(ADP mode only)

VSTAT Output Low Voltage STAT Pin Sinks 4mA 0.4 VISTAT STAT Pin Current Sink Capability 8.0 mAVOVP Over-Voltage Protection Threshold 4.4 VIOCP Over-Current Protection Threshold 105 %ICH_CC

Charge Termination Threshold Current 7.5 %

ITERM/ICHG

ITS Current Source from TS Pin 70 80 90 μA

TS1 TS Hot Temperature Fault Threshold 310 330 350

mVHysteresis 15

TS2 TS Cold Temperature Fault Threshold 2.2 2.3 2.4 VHysteresis 10 mV

TREG Thermal Loop Regulation 90 °CTLOOP_IN Thermal Loop Entering Threshold 110 °C

TLOOP_OUT Thermal Loop Exiting Threshold 85 °CTOVSD Over-Temperature Shutdown Threshold 145 °C



3690.2007.01.1.2 5

1. The AAT3690 output charge voltage is specified over the 0° to 70°C ambient temperature range; operation over the -40°C to +85°Ctemperature range is guaranteed by design.

Typical Characteristics

Adapter Charging Current vs. Battery Voltage(RADPSET = 8.06kΩΩ)

Battery Voltage (V)

I CH (

A)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

2.5 2.9 3.3 3.7 4.1 4.5

Fast Charge Current vs. Temperature(RADPSET = 8.06kΩΩ; RUSBSET = 8.06kΩ)

Temperature (°C)

I CH A

DP

(m

A) IC

H US

B (m

A)

900

920

940

960

980

1000

1020

1040

1060

1080

1100

-50 -25 0 25 50 75 100440

450

460

470

480

490

500

510

520

530

540

ADP

USB

End of Charge Voltage vs. Temperature

Temperature (°C)

V BA

T (V) ADP

USB

4.158

4.179

4.200

4.221

4.242

-50 -25 0 25 50 75 100

Recharge Voltage vs. Temperature

Temperature (°C)

V RC

H (V

)

4.04

4.05

4.06

4.07

4.08

4.09

4.10

4.11

4.12

4.13

4.14

-50 -25 0 25 50 75 100

USB

ADP

Battery Voltage vs. Supply Voltage

Supply Voltage (V)

V BA

T (V)

USB

ADP

4.158

4.179

4.200

4.221

4.242

4.5 4.75 5 5.25 5.5

IFASTCHARGE vs. RSET

RSET (kΩ)

I FAST

CH

AR

GE

(mA

)

10

100

1000

10000

1 10 100 1000

USB

ADP



6 3690.2007.01.1.2


VIL vs. Supply VoltageEN Pin (Falling)

Supply Voltage (V)

VIH

(V

)

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

1.3

1.4

4.2 4.4 4.6 4.8 5 5.2 5.4 5.6 5.8 6

-40°C 25°C

85°C

VIH vs. Supply VoltageEN Pin (Rising)

Supply Voltage (V)

VIH

(V

)

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

1.3

1.4

4.2 4.4 4.6 4.8 5 5.2 5.4 5.6 5.8 6

-40°C 25°C

85°C

USB Fast Charge Current vs. Supply Voltage(RUSBSET; USB = 8.06kΩΩ)

Supply Voltage (V)

I CH (

mA

)

0°C

0

100

200

300

400

500

600

4.4 4.5 4.6 4.7 4.8 4.9 5

25°C 70°C

USB Fast Charge Current vs. Supply Voltage(RUSBSET; USB = 8.06kΩΩ)

Supply Voltage (V)

I CH (

mA

)

0

100

200

300

400

500

600

4 4.25 4.5 4.75 5 5.25 5.5 5.75 6

VBAT = 3.3V

VBAT = 3.5VVBAT = 3.9V

Adapter Fast Charge Current vs. Supply Voltage(RADPSET = 8.06kΩΩ)

Supply Voltage (V)

I CH (

mA

)

0

200

400

600

800

1000

1200

4 4.5 5 5.5 6

VBAT = 3.3V

VBAT = 3.5V

VBAT = 3.9V

USB Charging Current vs. Battery Voltage(RUSBSET = 8.06kΩΩ)

Battery Voltage (V)

I CH (

mA

)

0

100

200

300

400

500

600

2.5 3 3.5 4 4.5



3690.2007.01.1.2 7


Temperature Sense Output Current

vs. Temperature

Temperature (°°C)

TS

Pin

Cu

rre

nt

(μA

)

72

74

76

78

80

82

84

86

88

-50 -25 0 25 50 75 100

CT Pin Capacitance vs. Counter Timeout

Time (hours)

Ca

pa

cit

an

ce

(µ

F)

0.0

0.1

0.2

0.3

0.4

0.5

0 2 4 6 8 10

Constant Current Timeout

Counter Timeout vs. Temperature(CT = 0.1μμF)

Temperature (°C)

Co

un

ter

Tim

eo

ut

(%)

-10

-8

-6

-4

-2

0

2

4

6

8

10

-50 -25 0 25 50 75 100

USB Charge Current vs. Time(RUSBSET = 8.06kΩ)

Time (sec)

USB VBUS(200mV/div)

USB ChargeCurrent

(100mA/div)

USB PeripheralCurrent

Consumption(100mA/div)

0 2 4 6 8 10

Charge ReductionMode Activated

Adapter Mode Supply Current

vs. ADPSET Resistor

ADPSET Resistor (kΩΩ)

I Q (

mA

)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

1 10 100 1000

Constant Current



8 3690.2007.01.1.2



3690.2007.01.1.2 9

Functional Block Diagram

ChargeControl

CurrentCompare

Reverse Blocking

Reverse Blocking

CV

USB

ConstantCurrent

CurrentCompare

ADP

BAT

ADPSET

UVLO

Over-Temperature

Protect

ChargeStatusSTAT2

STAT1

TSWindowComparator

80μA

USBSET

WatchdogTimer CT

GND

ChargeReduction

Loop

VoltageSense

EN

IC enable

Functional DescriptionThe AAT3690 is a highly integrated single-cell lithi-um-ion/polymer battery charger IC designed tooperate with USB port and AC adapter inputs, whilerequiring a minimum number of external compo-nents. The AAT3690 precisely regulates batterycharge voltage and current for 4.2V lithium-ion/poly-mer battery cells.

The adapter charge input constant current level canbe programmed up to 1.0A for rapid charging appli-cations. In the absence of a high-current adapterinput source, the AAT3690 can be powered from aUSB port VBUS supply. The USB constant chargecurrent can be externally programmed for maximumconstant current charge levels up to 1A.

The USB mode has an automatic ChargeReduction Loop control to allow users to chargethe battery with limited available current from aUSB port while maintaining the regulated port volt-

age. This system assures the battery charge func-tion will not overload a USB port while charging ifother system demands also share power with therespective port supply. The USB charge function isautomatically disabled when an adapter inputpower source greater than 4.4V is present.

Status monitor output pins are provided to indicatethe battery charge status by directly driving twoexternal LEDs.

Battery temperature and charge state are fully mon-itored for fault conditions. In the event of an over-voltage or over-temperature condition, the devicewill automatically shut down, thus protecting thecharging device, control system, and the batteryunder charge. In addition to internal charge con-troller thermal protection, the AAT3690 also providesa temperature sense feedback function (TS pin)from the battery to shut down the device in the eventthe battery exceeds its own thermal limit duringcharging.



10 3690.2007.01.1.2

Charging OperationRegardless of which charge input function is selected (i.e., either the adapter input or USB input), the AAT3690has three basic modes for the battery charge cycle: constant current/fast charge; constant voltage; and end ofcharge (see Figure 1).

Figure 1: Current vs. Voltage Profile During Charging Phases.

Constant CurrentCharge Phase

Constant VoltageCharge Phase

Charge Complete Voltage

Regulated Current I = Max CC

I = CC/10

Fast Charge / Constant Current ChargingWhen enabled, the AAT3690 begins constant-cur-rent fast charging. The fast charge ConstantCurrent (ICC) amplitude is determined by thecharge mode, ADP or USB, and is programmed bythe user via the RSETADP and RSETUSB resistors. TheAAT3690 remains in constant current charge modeuntil the battery reaches the voltage regulationpoint, VBAT.

Constant Voltage ChargingThe system transitions to a constant voltage charg-ing mode when the battery voltage reaches outputcharge regulation threshold (VBAT) during the con-stant current fast charge phase. The regulationvoltage level is factory programmed to 4.2V (±1%).The charge current in the constant voltage modedrops as the battery cell under charge reaches itsmaximum capacity.

End of Charge Cycle Termination andRecharge SequenceWhen the charge current drops to 7.5% of the pro-grammed fast charge current level in the constantvoltage mode, the device terminates charging andgoes into a standby state. The charger will remainin a standby state until the battery voltage decreas-es to a level below the battery recharge voltagethreshold (VRCH).

When the input supply is disconnected or dropsbelow UVLO or EN = 0, the charger will automati-cally enter power-saving sleep mode. Consumingan ultra-low 2μA in sleep mode, the AAT3690 min-imizes battery drain when it is not charging. Thisfeature is particularly useful in applications wherethe input supply level may fall below the batterycharge or under-voltage lockout level. In suchcases where the AAT3690 input voltage drops, thedevice will enter the sleep mode and automaticallyresume charging once the input supply has recov-ered from its fault condition.



3690.2007.01.1.2 11

System Operation Flow Chart

ShutdownMode

NoNo

No

Yes

No

Yes

No

YesYes

USB

ADP

Yes

Set

Expire

Power OnReset

Power OnReset

SleepMode

SleepMode

Power Select

USB Loop

No

YesNo

Yes

FaultConditions Monitor

OV, OT

Yes

No

ThermalLoop Enable

USB LoopCurrent

Reduction in USBCharging Mode

USB LoopCurrent

Reduction in USBCharging Mode

Timing

ADPLoop

No

Enable

Yes

UVLOVP > VUVLO

SwitchOn

Device Temp. MonitorTJ > 110°C

BatteryTemp. Fault

Thermal LoopCurrent

Reduction in ADPCharging Mode

ChargeSafetyTimer

CurrentCharging

Mode

BatteryTemp. Monitor

VTS1 < TS < VTS2

Current Phase TestVEOC > VBAT

Recharge TestVRCH > VBAT

Voltage Phase TestIBAT > ITERM

VoltageCharging

Mode

USB VoltageRegulation

EnableUSB Voltage Test

VUSB < 4.5VCharge

Completed



12 3690.2007.01.1.2

Application InformationAC Adapter / USB System Power Charging

Adapter ModeIn the adapter mode, constant current charge lev-els up to 1.0A can be programmed by the user. TheAAT3690 system control will always select theadapter input over the USB supply input wheneveradapter voltage is present on the ADP pin. TheAAT3690 will operate from the adapter input over a4.0V to 5.5V range.

The constant current fast charge current for theadapter input mode is set by the RSETADP resistorconnected between ADPSET and ground. Refer toTable 1 for recommended RSETADP values for adesired constant current charge level. The precisecharging function in the adapter mode may be readfrom the status LEDs. Please refer to the BatteryCharge Status Indication discussion in thisdatasheet for further details.

Thermal Loop ControlDue to the integrated nature of the linear chargingcontrol pass device for the adapter mode, a specialthermal loop control system has been employed tomaximize charging current under all operating con-ditions. The thermal management system meas-ures the internal circuit die temperature andreduces the fast charge current when the deviceexceeds a preset internal temperature controlthreshold. Once the thermal loop control becomesactive, the fast charge current is initially reduced bya factor of 0.44.

The initial thermal loop current can be estimated bythe following equation:

The thermal loop control re-evaluates the circuit dietemperature every three seconds and adjusts thefast charge current back up in small steps to the full

fast charge current level or until an equilibrium cur-rent is discovered and maximized for the givenambient temperature condition. In the manner thethermal loop controls the system charge level, theAAT3690 will always provide the highest level ofconstant current in the fast charge mode possiblefor any given ambient temperature condition.

Adapter Input Charge Inhibit and ResumeThe AAT3690 has an under-voltage lockout andpower on reset feature so that if the input supply tothe adapter pin drops below the UVLO thresholdthe charger will suspend charging and shut down.When power is re-applied to the adapter pin or theUVLO condition recovers and VADP > VBAT, the sys-tem charge control will assess the state of chargeon the battery cell and will automatically resumecharging in the appropriate mode for the conditionof the battery.

USB ModeThe AAT3690 provides an input for intelligent USBcharging. When no voltage is present on theadapter input pin, the charge controller will auto-matically switch to accepting power from the USBinput. The USB charge may be user programmedto any level between 50mA and 1A by selecting theappropriate resistor values for RSETUSB. Refer toTable 1 for recommended RSETUSB values for thedesired USB input constant current charge levels.

USB Charge ReductionIn many instances, product system designers donot know the real properties of a potential USB portused to supply power to the battery charger.Typically, powered USB ports found on desktopand notebook PCs should supply up to 500mA. Inthe event a USB port being used to supply thecharger is unable to provide the programmed fastcharge current or if the system under charge mustalso share supply current with other functions, theAAT3690 will automatically reduce USB fastcharge current to maintain port integrity and protectthe host system.

ITLOOP = ICC · 0.44



3690.2007.01.1.2 13

Table 1: Resistor Values.

The USB charge reduction system becomes activewhen the voltage on the USB input falls below theUSB charge reduction threshold, which is typically4.5V. The charge reduction system will reduce thefast charge current level in a linear fashion until thevoltage sensed on the USB input recovers abovethe charge reduction threshold voltage.

USB Input Charge Inhibit and ResumeThe AAT3690 UVLO and power on reset featurewill function when the USB input pin voltage leveldrops below the UVLO threshold. At this point, thecharger will suspend charging and shut down.When power is re-applied to the USB pin or theUVLO condition recovers, the system charge con-trol will assess the state of charge on the batterycell and will automatically resume charging in theappropriate mode for the condition of the battery.

Enable / DisableThe AAT3690 provides an enable function to con-trol the charger IC on and off. The enable (EN) pinis active high and is internally pulled up to the high-er voltage of ADP and USB supplies. When pulledto a logic low level, the AAT3690 will be shut down

and forced into the sleep state. Charging will behalted regardless of the battery voltage or chargingstate. When the device is re-enabled, the chargecontrol circuit will automatically reset and resumecharging functions with the appropriate chargingmode based on the battery charge state and meas-ured cell voltage.

Programming Charge CurrentThe fast charge constant current charge level forboth Adapter and USB input modes are pro-grammed with set resistors placed between theADPSET and USBSET pins and ground. The accu-racy of the fast charge is dominated by the toler-ance of the set resistor used. For this reason, 1%tolerance metal film resistors are recommended forthe set resistor function.

ADP fast charge constant current levels from 100mAto 1.0A may be set by selecting the appropriateresistor value from Table 1.

The USB charge may be set to any level between50mA and 1.0A depending upon the system designrequirements for a given USB charge application.Refer to Table 1 and Figure 2 for recommendedRSETUSB values.

Figure 2: IFASTCHARGE vs. RSET.

RSET (kΩΩ)

I FA

ST

CH

AR

GE (

mA

)

10

100

1000

10000

1 10 100

USB

ADP

ADP USBICC RSET (kΩΩ) RSET (kΩΩ)50 N/A 86.675 N/A 57.6

100 84.5 42.2200 43.2 21.0300 28.0 13.7400 21.0 10.2500 16.9 8.06600 13.3 6.65700 11.5 5.62800 10.2 4.87900 9.09 4.32

1000 8.06 3.83



14 3690.2007.01.1.2

Protection Circuitry

Programmable Watchdog TimerThe AAT3690 contains a watchdog timing circuit forthe adapter input charging mode. No watchdog tim-ing functions are active for the USB input mode.Typically, a 0.1μF ceramic capacitor is connectedbetween the CT pin and ground. When a 0.1μFceramic capacitor is used, the device will time ashutdown condition if the fast charge modeexceeds three hours. When the device transitionsto the constant voltage mode, the timing counter isreset and will time out after three hours and shutdown the charger.

Summary for a 0.1μF Used for the Timing Capacitor.

The CT pin is driven by a constant current sourceand will provide a linear response to increases inthe timing capacitor value. Thus, if the timingcapacitor were to be doubled from the nominal0.1μF value, the time-out times would be doubled.

If the programmable watchdog timer function is notneeded, it may be disabled by connecting the CTpin to ground. The CT pin should not be left float-ing or un-terminated, as this will cause errors in theinternal timing control circuit.

The constant current provided to charge the timingcapacitor is very small, and this pin is susceptibleto noise and changes in capacitance value.Therefore, the timing capacitor should be physical-ly located on the printed circuit board layout asclosely as possible to the CT pin. Since the accu-racy of the internal timer is dominated by thecapacitance value, 10% tolerance or better ceram-ic capacitors are recommended. Ceramic capacitormaterials such as X7R and X5R type are a goodchoice for this application.

Over-Voltage ProtectionAn over-voltage event is defined as a conditionwhere the voltage on the BAT pin exceeds the max-imum battery charge voltage and is set by the over-voltage protection threshold (VOVP). If an over-volt-age condition occurs, the AAT3690 charge controlwill shut down the device until voltage on the BATpin drops below the over-voltage protection thresh-old (VOVP). The AAT3690 will resume normal charg-ing operation after the over-voltage condition isremoved. During an over-voltage event, the STATLEDs will report a system fault.

Over-Temperature ShutdownThe AAT3690 has a thermal protection control cir-cuit which will shut down charging functions shouldthe internal die temperature exceed the presetthermal limit threshold.

Battery Temperature Fault MonitoringIn the event of a battery over-temperature condi-tion, the charge control will turn off the internal passdevice. The STAT LEDs will display a system fault.After the system recovers from a temperature fault,the device will resume charging operation.

The AAT3690 checks battery temperature beforestarting the charge cycle, as well as during allstages of charging. This is accomplished by moni-toring the voltage at the TS pin. This system isintended to use negative temperature coefficient(NTC) thermistors, which are typically integratedinto the battery package. Most commonly usedNTC thermistors used in battery packs are approx-imately 10kΩ at room temperature (25°C).

The TS pin has been specifically designed tosource 80μA of current to the thermistor. The volt-age on the TS pin that results from the resistiveload should stay within a window from 335mV to2.32V. If the battery becomes too hot during charg-ing due to an internal fault, the thermistor will heatup and reduce in value, thus pulling the TS pin volt-age lower than the TS1 threshold and the AAT3690will signal the fault condition.

If the use of the TS pin function is not required bythe system, it can be left open or terminated toground using a 10kΩ resistor.

Mode TimeFast Charge (CC) Time Out 3 hoursConstant Voltage (CV) Mode 3 hoursTime Out



3690.2007.01.1.2 15

Battery Charge Status IndicationThe AAT3690 has two status LED driver outputs.These two LEDs can indicate simple functionssuch as no battery charge activity, battery charg-ing, charge complete, and charge fault.

Status Indicator DisplaySimple system charging status may be displayedusing one or two LEDs in conjunction with the STAT1and STAT2 pins on the AAT3690. These two pins aresimple switches to connect the LED cathodes toground. It is not necessary to use both display LEDsif a user simply wants to have a single lamp to show"charging" or "not charging." This can be accom-plished by using the STAT1 pin and a single LED.Using two LEDs and both STAT pins simply gives theuser more information to the charging states. Referto Table 2 for LED display definitions.

The LED anodes should be connected to eitherVUSB or VADP, depending upon the system designrequirements. The LEDs should be biased with aslittle current as necessary to create reasonable illu-mination; therefore, a ballast resistor should beplaced between the LED cathodes and theSTAT1/2 pins. LED current consumption will add tothe overall thermal power budget for the devicepackage, so it is wise to keep the LED drive currentto a minimum. 2mA should be sufficient to drivemost low-cost green or red LEDs. It is not recom-mended to exceed 8mA for driving an individualstatus LED. The required ballast resistor value canbe estimated using the following formulas:

For connection to the adapter supply:

Example:

Note: Red LED forward voltage (VF) is typically2.0V @ 2mA.

For connection to the USB supply:

Example:

Note: Green LED forward voltage (VF) is typically3.2V @ 2mA.

The status LED display conditions are described inTable 2.

RB(STAT2) = = 900Ω5.0V - 3.2V

2mA

RB(STAT1/2) = VUSB - VF(LED)

ILED(STAT1/2)

RB(STAT1) = = 1.75kΩ5.5V - 2.0V

2mA

RB(STAT1/2) = VADP - VF(LED)

ILED(STAT1/2)

Table 2: Status LED Display Conditions.

Event Description STAT1 STAT2Charge Disabled or Low Supply Off OffCharge Enabled Without Battery Flash1 Flash1

Battery Charging On OffCharge Completed Off OnFault On On

1. Flashing rate depends on output capacitance.



16 3690.2007.01.1.2

Thermal ConsiderationsThe AAT3690 is offered in a 3x3mm TDFN pack-age which can provide up to 2.0W of power dissi-pation when it is properly bonded to a printed cir-cuit board and has a maximum thermal resistanceof 50°C/W. Many considerations should be takeninto account when designing the printed circuitboard layout, as well as the placement of thecharger IC package in proximity to other heat gen-erating devices in a given application design. Theambient temperature around the charger IC willalso have an effect on the thermal limits of a bat-tery charging application. The maximum limits thatcan be expected for a given ambient condition canbe estimated by the following discussion:

First, the maximum power dissipation for a givensituation should be calculated:

Eq. 1:

Where:

PD = Total power dissipation by the device

VIN = Either VADP or VUSB, depending on whichmode is selected

VBAT = Battery voltage as seen at the BAT pin

ICC = Maximum constant fast charge current pro-grammed for the application

IOP = Quiescent current consumed by the charg-er IC for normal operation

Next, the maximum operating ambient temperaturefor a given application can be estimated based onthe thermal resistance of the 3x3 TDFN packagewhen sufficiently mounted to a PCB layout and theinternal thermal loop temperature threshold.

Eq. 2:

Where:

TA = Ambient temperature in degrees C

TJ = Maximum device junction temperaturebelow the thermal loop threshold

PD = Total power dissipation by the device

θJA = Package thermal resistance in °C/W

Example:

For an application where the fast charge current forthe adapter mode is set to 0.75A, VADP = 5.0V, andthe worst case battery voltage is 3.6V, what is themaximum ambient temperature where the thermallimiting will become active?

Given:

VADP = 5.0V

VBAT = 3.6V

ICC = 0.75A

IOP = 0.75mA

TJ = 110°C

θJA = 50°C/W

Using Equation 3, calculate the device power dissi-pation for the stated condition:

Eq. 3:

The maximum ambient temperature before theAAT3690 thermal loop becomes active can now becalculated using Equation 4:

Eq. 4:

Therefore, under the stated conditions for thisworst case power dissipation example, theAAT3690 will enter the thermal loop and lower thefast charge constant current when the ambientoperating temperature rises above 24.8°C.

TA = 110°C - (50°C/W · 1.05375W)

= 57.3125°C

PD = (5.0V - 3.6V)(0.75A) + (5.0V · 0.75mA) = 1.05375W

TA = TJ - (θJA · PD)

PD = [(VIN - VBAT) · ICC + (VIN · IOP)]



3690.2007.01.1.2 17

Capacitor Selection

Input CapacitorIn general, it is good design practice to place adecoupling capacitor between the ADP and USBpins and ground. An input capacitor in the range of1μF to 22μF is recommended. If the source supplyis unregulated, it may be necessary to increase thecapacitance to keep the input voltage above theunder-voltage lockout threshold during deviceenable and when battery charging is initiated.

If the AAT3690 adapter input is to be used in a sys-tem with an external power supply source, such asa typical AC-to-DC wall adapter, then a CIN capaci-tor in the range of 10μF should be used. A largerinput capacitor in this application will minimizeswitching or power bounce effects when the powersupply is "hot plugged." Likewise, a 10μF or greaterinput capacitor is recommended for the USB inputto help buffer the effects of USB source powerswitching, noise, and input cable impedance.

Output CapacitorThe AAT3690 only requires a 1μF ceramic capaci-tor on the BAT pin to maintain circuit stability. Thisvalue should be increased to 10μF or more if thebattery connection is made any distance from thecharger output. If the AAT3690 is to be used inapplications where the battery can be removedfrom the charger, such as in the case of desktopcharging cradles, an output capacitor greater than10μF may be required to prevent the device fromcycling on and off when no battery is present.

Printed Circuit Board LayoutConsiderationsFor the best results, it is recommended to physical-ly place the battery pack as close to the AAT3690BAT pin as possible. To minimize voltage drops onthe PCB, keep the high current carrying traces ade-quately wide. For maximum power dissipation ofthe AAT3690 TDFN package, the metal substrateshould be solder bonded to the board. It is also rec-ommended to maximize the substrate contact to thePCB ground plane layer to further increase localheat dissipation.

Figure 3: AAT3690 Evaluation Board Schematic.

D2 D1

R18.06K

R51.5K

R41.5K

R310K

R28.06KC1

10μFC210μF

C310μF

C40.1μF

BAT

ADP

USB

CT

TS

1 2 3

ON/OFF

J1

GND 4

USB1

BAT2

ADP3

USBSET 11

EN5 USB 10

TS6

CT9

STAT2 7

STAT1 8

ADPSET 12

AAT3690

U10

J2

DS1 (a)BAV74LT1

DS1 (b)BAV74LT1

GRNLED

REDLED

Figure 4: AAT3690 Evaluation Board Figure 5: AAT3690 Evaluation Board Top Side Layout. Bottom Side Layout.

Table 3: AAT3690 Evaluation Board Bill of Materials.

Component Part Number Description ManufacturerU1 AAT3690IWP-4.2-T1 1.0A USB Port/Adapter Lithium-Ion/ AnalogicTech

Polymer Battery Charger; 12-Pin 3x3 TDFN Package

R1, R2 Chip Resistor 8.06KΩ, 1%, 1/4W; 0603 VishayR3 Chip Resistor 10KΩ, 5%, 1/4W; 0603 Vishay

R4, R5 Chip Resistor 1.5KΩ, 5%, 1/4W; 0603 VishayC1, C2, C3 GRM21BR61A106KE19 CER 10μF 10V 10% X5R 0805 Murata

C4 GRM188R71C104KA01 CER 0.1μF 16V 10% X7R 0603 MurataJP1 PRPN401PAEN Conn. 3-pin Header, 2mm zip Sullins ElectronicsJP2 Chip Resistor 0Ω VishayD1 CMD15-21SRC/TR8 Red LED; 1206 Chicago Miniature LampD2 CMD15-21VGC/TR8 Green LED; 1206 Chicago Miniature Lamp

DS1 (a, b) BAV74LT-A Default Diode; SOT23-3 On Semi



18 3690.2007.01.1.2



3690.2007.01.1.2 19

Ordering Information

Package Information3

TDFN33-12

All dimensions in millimeters.

Top View Bottom View

Detail "A"

Side View

3.00 ± 0.05

Index Area Detail "A"

1.70 ± 0.05

3.00

± 0

.05

0.05 ± 0.05 0.23

± 0

.05

0.75

± 0

.05

2.40

± 0

.05

Pin 1 Indicator(optional)

0.43 ± 0.05

0.45

± 0

.05

0.23

± 0

.05

0.1 REF

All AnalogicTech products are offered in Pb-free packaging. The term “Pb-free” means semiconductor products that are in compliance with current RoHS standards, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. For more information, please visit our website at http://www.analogictech.com/pbfree.

Package Marking1 Part Number (Tape and Reel)2

TDFN33-12 RUXYY AAT3690IWP-4.2-T1

1. XYY = assembly and date code.2. Sample stock is generally held on part numbers listed in BOLD.3. The leadless package family, which includes QFN, TQFN, DFN, TDFN and STDFN, has exposed copper (unplated) at the end of the

lead terminals due to the manufacturing process. A solder fillet at the exposed copper edge cannot be guaranteed and is not requiredto ensure a proper bottom solder connection.



20 3690.2007.01.1.2

Advanced Analogic Technologies, Inc.830 E. Arques Avenue, Sunnyvale, CA 94085Phone (408) 737-4600Fax (408) 737-4611

© Advanced Analogic Technologies, Inc.

AnalogicTech cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in an AnalogicTech product. No circuit patent licenses, copyrights, mask work rights,or other intellectual property rights are implied. AnalogicTech reserves the right to make changes to their products or specifications or to discontinue any product or service without notice.Customers are advised to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold sub-ject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability. AnalogicTechwarrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with AnalogicTech’s standard warranty. Testing and other quality con-trol techniques are utilized to the extent AnalogicTech deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed.

AnalogicTech and the AnalogicTech logo are trademarks of Advanced Analogic Technologies Incorporated. All other brand and product names appearing in this document are regis-tered trademarks or trademarks of their respective holders.

Documents

1.0A USB Port/Adapter Lithium-Ion/Polymer Battery Charger - AATI/AAT3690IWP-4.2... · 1.0A USB Port/Adapter Lithium-Ion/Polymer Battery Charger 3690.2007.01.1.2 1 BatteryManager™