MAX7400MAX7407

8/18/2019 MAX7400MAX7407

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General Description The M A X7400/M A X7403/M A X7404/M A X7407 8th-order,low pass, ellip tic, sw itched-capacitor filters (SC Fs) oper-ate from a sing le + 5V (M A X7 400/M A X7 403) or + 3V(M A X7 404/M A X74 07) supp ly. These d evices draw 2m Aof sup p ly c urrent an d allow co rne r freq uen cies from1H z to 10 kH z, m aking them id ea l for low -p ow er an ti-aliasing and post-D A C filtering app lications. They fea-ture a shutdow n m od e that red uces the sup p ly currentto 0.2µA .T w o c lo cking op tions a re a va ila b le : se lf-c loc king(through the u se of an e xternal cap acitor) or externalclocking for tighter cutoff-frequency c ontrol. In addition,an offset ad justm en t p in (O S) allow s for the ad justm en t

of the D C output level.The M A X74 00/M A X74 04 provide 82d B of stopb andrejection and a sh arp rolloff w ith a transition ratio of 1.5.The M A X7403 /M A X7407 provide a sharper rolloff w ith atransition ratio of 1.2, w hile still delive ring 60dB of stop -b an d rejec tion . Th e fixed resp on se of the se d evice ssim plifies the design task to corner-frequency se lectionb y setting a c lock freq ue ncy. Th e M A X 740 0/M A X7 403/M A X7404/M A X7407 are availab le in 8-p in S Oand D IP p ackages.

Applications A D C A nti-A liasing S peech P rocessing

P ost-D A C F ilte rin g A ir-B a g E le ctro nic s

C T2 B ase S tations

Features 8th-Order Lowpass Elliptic Filter

Low Noise and Distortion-82dB THD + Noise (MAX7400)

Clock-Tunable Corner Frequency (1Hz to 10kHz)

100:1 Clock-to-Corner Ratio Single-Supply Operation

+5V (MAX7400/MAX7403)+3V (MAX7404/MAX7407)

Low Power2mA (Operating Mode)0.2µA (Shutdown Mode)

Available in 8-Pin SO and DIP Packages Low Output Offset: ±5mV

MAX74 0 0 / MAX74 0 3 / MAX74 04 / MAX74 07

8th-Order, Lowpass, Elliptic,Switched-Capacitor Filters

________________________________________________________________ Maxim Integrated Products 1

VDD

IN

CLK

OUT

GND

INPUT

0.1µF

0.1µF

CLOCK

SHDN

OUTPUT

VSUPPLY

COM

OS

MAX7400 MAX7403 MAX7404 MAX7407 OS

OUTVDD

1

2

8

7

CLK

SHDNIN

GND

COM

SO/DIP

TOP VIEW

3

4

6

5

MAX7400 MAX7403 MAX7404 MAX7407

Typical Operating Circuit

19 -47 64 ; R ev 2 ; 6/99

Ordering Information continued at end of data sheet.

Pin Configuration

Ordering Information

Selector Guide

M A X7407 Ellip tic (r = 1.2) + 3

PART FILTER RESPONSE OPERATINGVOLTAGE (V)

M A X 7 40 3

M A X7400 Ellip tic (r = 1.5) + 5

Ellip tic (r = 1.2) + 5

M A X7404 Ellip tic (r = 1.5) + 3

PARTMAX7400 C SAM A X 7 40 0C PAM A X 7400E SA -40°C to + 85°C

0°C to + 70°C0°C to + 70°C

TEMP. RANGE PIN-PACKAGE8 SO8 Plastic D IP8 SO

M A X7400E PA -40°C to + 85°C 8 Plastic D IP

For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.For small orders, phone 1-800-835-8769.

8/18/2019 MAX7400MAX7407


M A X 7 4 0 0 / M A X 7 4 0 3 / M A X 7 4 0 4 / M A X 7 4 0 7


2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS—MAX7400/MAX7403(VD D = + 5V , filter ou tput m easured at O U T, 10 k Ω || 50p F load to G N D at O U T, SHDN = VD D, O S = C O M , 0.1µF from C O M to G N D ,fC LK= 100kH z, T A = TM IN to T M A X, un less othe rw ise no ted . Typica l value s are a t + 25 °C .)

Stresse s b eyond those listed under “A bsolute M axim um R ating s”m ay c ause p erm anen t dam ag e to the device . These are stress rating s on ly, and functionalop eration of the device at the se or any othe r co nd ition s b eyon d tho se ind ica ted in the o peration al section s of the sp ec ifica tion s is not im p lied . Exp osure to ab solute m axim um rating co nd ition s for exten ded period s m ay affec t device reliab ility.

VD D to G N DM A X7400/M A X7403 ..............................................-0.3V to + 6VM A X7404/M A X7407 ..............................................-0.3V to + 4V

IN , O U T, C O M , O S, C LK ............................-0.3V to (V D D+ 0.3V) SHDN ........................................................................-0.3V to +6VO U T Short-C ircuit D uration ...................................................1sec

C ontinuous P ow er D issipation (T A = + 70°C )SO (derate 5.88m W /°C above + 70°C )..........................471m WD IP (derate 9.1m W /°C above + 70°C )...........................727m W

O perating Tem perature R ang esM A X740_C _A .....................................................0°C to + 70°CM A X740_E_A ..................................................-40°C to + 85°C

Storag e Tem perature R ange .............................-65 °C to + 150°CLead Tem perature (soldering, 10se c).............................+ 300°C

VO S = 0 to (V D D - 1V ) (N ote 3 )

(N ote 1 )

SHDN = G N D , VC O M

= 0 to VD D

VIN = VC O M= VD D / 2

O utput, C O M internally b iase d

VC O M= VD D / 2 (N ote 2)

Inp ut, C O M externally d riven

CONDITIONS

µA± 0.1 ± 10Inp ut Leakage C urrent at O S

µA± 0.1 ± 10Inp ut Leakag e C urrent at C O M

pF50 500CLM axim um C ap acitive Loadat O U T

kΩ10 1RLR esistive O utput Lo ad D rive

m Vp-p10C lock Feed throug h

kΩ75 125RC O MInp ut R esistance at C O M

VD D/ 2VD D/ 2

VD D/ 2- 0.2 + 0.2

VC O MC O M Voltage R ange V

VD D/ 2VD D/ 2

VD D/ 2- 0.5 + 0.5

100:1fC LK/f CC loc k-to-C orner R atio

kH z0.001 to 1 0fCC orner Freq uency

VVC O M± 0.1VO SInp ut Voltag e R ange at O S

-82

pp m /°C10C lock-to-C orner Tem pco

V0.25 V D D - 0.25O utpu t Vo ltag e R ang e

m V± 5 ± 25VO FFSETO utput O ffset Voltag e

dB-0.1 0.15 0.3D C Inse rtion G ain w ithO utpu t O ffset R em oved

UNITSMIN TYP MAXSYMBOLPARAMETER

CO SC = 1000pF (N ote 4) kH z29 38 48fO SCInternal O scillator Frequency

VC LK= 0 or 5V µA± 15 ± 30IC LKC lock Inp ut C urren t

VD D - 0.5VIH V

0.5VIL

C lock Inp ut H igh

fIN = 200H z, V IN = 4Vp-p,m easurem ent band w idth = 22kH z dB

-80T H D + N

To tal H arm on ic D istortionp lus N oise

M A X 7 40 0

M A X 7 40 3

V /V1AO SO S V oltage G ain to O U T

C lock Input Low V

FILTER CHARACTERISTICS

CLOCK

8/18/2019 MAX7400MAX7407


MAX74 0 0 / MAX74 0 3 / MAX74 04 / MAX74 07


_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS—MAX7400/MAX7403 (continued)(VD D = + 5V , filter ou tput m ea sured at O U T, 10k Ω || 50p F load to G N D at O U T, SHDN = VD D, O S = C O M , 0.1µF from C O M to G N D ,fC LK= 100kH z, T A = TM IN to T M A X, un less o therw ise no ted . Typica l values are at T A = + 25°C .)

ELECTRICAL CHARACTERISTICS—MAX7404/MAX7407(VD D = + 3V , filter ou tput m easured at O U T, 10 k Ω || 50p F load to G N D at O U T, SHDN = VD D, O S = C O M , 0.1µF from C O M to G N D ,fC LK= 100kH z, T A = TM IN to T M A X, un less o the rw ise no ted . Typica l value s a re at T A = + 25°C .)

SHUTDOWN

POWER REQUIREMENTS

SHDN Inp ut Leakage C urrent ± 0.1 ± 10 µAV SHDN = 0 to V D D

SHDN Inp ut H igh

VSD L 0.5

VVSD H VD D - 0.5

PARAMETER SYMBOL MIN TYP MAX UNITS

Pow er-Supply R ejection R atio PSR R 60 dB

Shutdow n C urrent I SHDN 0.2 1 µA

Supply Voltage V D D 4.5 5.5 V

Supply C urrent I D D 2 3.5 m A

CONDITIONS

M easured at D C

SHDN = G N D , C LK driven from 0 to V D D

O perating m ode, no load, IN = O S = C O M

FILTER CHARACTERISTICS

Total H arm on ic D istortionp lus N oise

PARAMETER SYMBOL MIN TYP MAX UNITS

D C Insertion G ain w ith O utputO ffset R em oved

-0.1 0.1 0.3 dB

O utput O ffset Voltage VO FFSET

± 5 ± 25 m V

O utput Voltage R ange 0.25 V D D - 0.25 V

C lock-to-C orner Tem pco 10 ppm /°C

T H D + N-77

dBM A X 7 40 7

M A X7404 -79

O S Voltage G ain to O U T A O S 1 V/V

Input Voltage R ange at O S V O S VC O M± 0.1 V

C orner Frequency f C 0.001 to 10 kH z

C lock-to-C orner R atio f C LK/f C 100:1

VD D/ 2VD D/ 2

VD D/ 2- 0.1 + 0.1

VC O M Voltage R ange V C O M

Input R esistance at C O M R C O M 75 125 kΩ

C lock Feedthrough 10 m Vp-p

R esistive O utp ut Load D rive R L 10 1 kΩ

M axim um C apa citive Loadat O U T

CL 50 500 pF

Input Leakage C urrent at C O M ± 0.1 ± 10 µAInput Leakage C urrent at O S ± 0.1 ± 10 µA

CONDITIONS

C O M internally b iased or externally d riven

VC O M= VD D / 2 (N ote 2)

VIN

= VC O M

= VD D

/ 2

fIN = 200H z, V IN = 2.5V p-p,m easurem ent band w idth = 22kH z

SHDN = G N D , VC O M= 0 to V D D

(N ote 1 )

VO S = 0 to (V D D - 1V ) (N ote 3 )

SHDN Inp ut Low V

8/18/2019 MAX7400MAX7407


M A X 7 4 0 0 / M A X 7 4 0 3 / M A X 7 4 0 4 / M A X 7 4 0 7


4 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS—MAX7404/MAX7407 (continued)(VD D = + 3V , filter ou tput m ea sured at O U T, 10k Ω || 50p F load to G N D at O U T, SHDN = VD D, O S = C O M , 0.1µF from C O M to G N D ,fC LK= 100kH z, T A = TM IN to T M A X, un less o therw ise no ted . Typica l values are at T A = + 25°C .)

ELLIPTIC (r = 1.5) FILTER CHARACTERISTICS—MAX7400/MAX7404(VD D = + 5V for M A X7400, V D D = + 3V for M A X7404; filter ou tput m easured at O U T; 10k Ω || 50pF load to G N D at O U T; SHDN = VD D;VC O M= VO S = VD D/ 2; f C LK= 100kH z; T A = TM IN to T M A X; un less o the rw ise noted . Typ ical value s a re at T A = + 25°C .)

VC LK= 0 or 3V

CO SC = 1000p F (N ote 4)

V

CONDITIONS

VD D - 0.5VIH

µA± 15 ± 30IC LKC lock Inp ut C urren t

kH z26 34 43fO SCInternal O scillator Frequency

0.5VIL

C lock Inp ut H igh

UNITSMIN TYP MAXSYMBOLPARAMETER

SHDN = G N D , C LK driven from 0 to V D D

O perating m ode, no load, IN = O S = C O M

M easured at D CµA0.2 1I SHDN

m A2 3.5ID DSu pp ly C urrent

V2.7 3.6VD DSup ply Voltag e

60P S R RSh utdow n C urrentPow er-Supp ly R ejection R atio dB

VD D - 0.5VSD H SHDN Inp ut H igh V

V SHDN = 0 to V D D ± 0.1 ± 10 SHDN Inp ut Lea kage C urrent µAVSD L 0.5

C lock Inp ut Low

SHDN Inp ut Lo w

V

V

CLOCK

POWER REQUIREMENTS

SHUTDOWN

dB

CONDITIONS UNITSMIN TYP MAXPARAMETERfIN = 0.371f C -0.20 -0.10 0.20

fIN = 0.737 f C

fIN = 0.587 f C

-0.20 -0.08 0.20

-0.20 0.02 0.20

fIN = 0.940 f C

fIN = 0.868 f C

-0.20 -0.03 0.20

fIN = 1.000 f C

fIN = 0.988 f C

-0.20 0.02 0.25

-0.20 0.09 0.25

-0.20 0.06 0.20

fIN = 1.601 f C

fIN = 1.500 f C

-84 -78

fIN = 4.020f C

fIN = 2.020 f C

-85 -78

Insertion G ain R elative to D C G ain(N ote 5 )

-83 -78

-82 -75

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_______________________________________________________________________________________ 5

Note 1: The m axim um fC is d efine d as the clock freq ue nc y, f C LK= 100 · fC, at w hich the pe ak S IN A D drop s to 68d B w ith asinusoidal input at 0.2f C.

Note 2: D C insertion gain is d efine d as ∆ VO U T/ ∆ VIN .Note 3: O S voltag es ab ove V D D - 1V saturate the inp ut an d result in a 75 µA typ ica l inp ut lea kage cu rren t.Note 4: For M A X7400/M A X7403, fO SC (kH z) ≅ 38 · 10 3 / C O SC (pF). For M A X74 04/M A X7 407, f O SC (kH z) ≅ 34 · 10 3 / C O SC (pF).Note 5: Th e input freq uen cies, f IN , are selec ted at the peaks an d troughs o f the freq uenc y resp onses.

ELLIPTIC (r = 1.2) FILTER CHARACTERISTICS—MAX7403/MAX7407(VD D = + 5V for M A X7403, V D D = + 3V for M A X7407; filter ou tput m easured at O U T; 10k Ω || 50pF load to G N D at O U T; SHDN = VD D;VC O M= VO S = VD D/ 2; f C LK= 100kH z; T A = TM IN to T M A X; un less o the rw ise noted . Typ ical value s a re at T A = + 25°C .)

Typical Operating Characteristics (VD D = + 5V for M A X7400/M A X7403, V D D = + 3V for M A X7404/M A X7407; VC O M= V O S = V D D / 2; SHDN = V D D; f C LK = 100kH z;TA = + 25 °C ; un less othe rw ise noted .)

-120

-80

-100

-40

-60

0

-20

20

0 1 2 3 4 5

MAX7400/MAX7404 (r = 1.5)FREQUENCY RESPONSE

M A X 7 4 0 0 / 0 3

- 0 1

INPUT FREQUENCY (kHz)

G A I N

( d B )

fC = 1kHz

-0.08

0

-0.04

0.12

0.08

0.04

0.20

0.16

0.24

0 202 404 606 808 1010

MAX7400/MAX7404 (r = 1.5)PASSBAND FREQUENCY RESPONSE

M A X 7 4 0 0 / 0 3

- 0 2

INPUT FREQUENCY (Hz)

G A I N

( d B )

fC = 1kHz

-640

-480

-560

-240

-320

-400

-8 0

-160

0

0 300 600 900 1200 1500

MAX7400/MAX7404 (r = 1.5)PHASE RESPONSE

M A X 7 4 0 0 / 0 3

- 0 3


P H A S E S H I F T ( D E G R E E S )

fC = 1kHz

PARAMETER MIN TYP MAX UNITS

-58 -50

-60 -54

Insertion G ain R elative to D C G ain(N ote 5 )

-60 -54

fIN = 1.533 f C

dB

fIN = 2.875f C

-59 -54

fIN = 1.200 f C

fIN = 1.261 f C

-0.20 0.10 0.20

-0.20 0.14 0.30

CONDITIONS

-0.20 0.09 0.30

fIN = 0.992 f C

fIN = 1.000 f C

-0.20 0.02 0.20

fIN = 0.902 f C

fIN = 0.956 f C

-0.20 0.02 0.20

-0.20 -0.06 0.20

fIN = 0.640 f C

fIN = 0.784 f C

-0.20 -0.11 0.20fIN = 0.408f C

MAX74 0 0 / MAX74 0 3 / MAX74 04 / MAX74 07

8/18/2019 MAX7400MAX7407


M A X 7 4 0 0 / M A X 7 4 0 3 / M A X 7 4 0 4 / M A X 7 4 0 7


6 _______________________________________________________________________________________

Typical Operating Characteristics (continued) (VD D = + 5V for M A X7400/M A X7403, V D D = + 3V for M A X7404/M A X7407; VC O M= V O S = V D D / 2; SHDN = V D D; f C LK = 100kH z;TA = + 25 °C ; un less othe rw ise noted .)

1.5

1.8

1.7

1.6

1.9

2.0

2.1

2.2

2.3

2.4

2.5

2.5 3.53.0 4.0 4.5 5.0 5.5

SUPPLY CURRENTvs. SUPPLY VOLTAGE

M A X 7 4 0 0 t o c

0 7

SUPPLY VOLTAGE (V)

S U P P L Y C U R R E N T ( m A )

NO LOAD

MAX7404MAX7407

MAX7400MAX7403

1.97

1.99

1.98

2.01

2.00

2.02

2.03

-40 20 40-20 0 60 80 100

SUPPLY CURRENTvs. TEMPERATURE

M A X 7 4 0 0 t o c

0 8

TEMPERATURE (°C)

S U P P L Y C U R R E N T ( m A )

NO LOAD

MAX7400MAX7403

MAX7404MAX7407

-20

-15

-10

-5

0

5

10

15

20

2.5 3.53.0 4.0 4.5 5.0 5.5

OFFSET VOLTAGEvs. SUPPLY VOLTAGE

M A X 7 4 0 0 t o c

0 9

SUPPLY VOLTAGE (V)

O F F S E T V O L T A G E ( m V )

VIN = VCOM = VDD /2

MAX7404MAX7407

MAX7400MAX7403

-0.5

0

0.5

1.5

1.0

2.0

-40 -20 0 20 40 60 80 100

OFFSET VOLTAGE vs. TEM PERATURE

M A X 7 4 0 0 / 0 3

- 1 0

TEMPERATURE (°C)

O F F S E T V O L T A G E ( m V )

VIN = VCOM = VDD /2

-9 0

-7 0

-8 0

-5 0

-6 0

-4 0-3 0

-1 0

-2 0

0

0 1 2 3 4 5

THD PLUS NOISE vs. INPUT SIGNALAMPLITUDE (MAX740 0)

M A X 7 4 0 0 / 0 3 1 1

AMPLITUDE (Vp-p)

T H D

+ N O I S E ( d B )

NO LOAD(SEE TABLE A)

BC

D

-9 0

-7 0

-8 0

-5 0

-6 0

-4 0-3 0

-1 0

-2 0

0

0 1 2 3 4 5

THD PLUS NOISE vs. INPUT SIGNAL AM PLITUDE AND RESISTIVE LOAD (MAX7 400)

M A X 7 4 0 0 / 0 3

- 1 2

AMPLITUDE (Vp-p)

T H D

+ N O I S E ( d B )

fIN = 200HzfC = 1kHzMEASUREMENT BW = 22kHz

RL = 500Ω

RL = 1kΩ

RL = 10kΩ

-120

-8 0

-100

-6 0

0

20

-2 0

-4 0

40

0 1 2 3 4 5

MAX7403/MAX7407 (r = 1.2)FREQUENCY RESPONSE

M A X 7 4 0 0 / 0 3 0 4

INPUT FREQUENCY (kHz)

G A I N

( d B )

fC = 1kHz

-0.32

-0.16

-0.24

-0.08

0.16

0.24

0.08

0

0.32

0 202 404 606 808 1010

MAX7403/MAX7407 (r = 1.2)PASSBAND FREQUENCY RESPONSE

M A X 7 4 0 0 / 0 3 0 5


G A I N

( d B )

fC = 1kHz

-640

-480

-560

-400

-160

-8 0

-240

-320

0

0 240 480 720 960 1200

MAX7403/MAX7407 (r = 1.2)PHASE RESPONSE

M A X 7 4 0 0 / 0 3 0 6


P H A S E S H I F T ( D E G R E E S )

fC = 1kHz

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MAX74 0 0 / MAX74 0 3 / MAX74 04 / MAX74 07


_______________________________________________________________________________________ 7

-9 0

-7 0-8 0

-5 0

-6 0

-4 0

-3 0

-1 0

-2 0

0

0 1 2 3 4 5

THD PLUS NOISE vs. INPUT SIGNAL AMPLITUDE (MAX740 3)

M A X 7 4 0 0 / 0 3 1 3

AMPLITUDE (Vp-p)

T H D

+ N O I S E ( d B )


BC

D

-9 0

-7 0-8 0

-5 0

-6 0

-4 0

-3 0

-1 0

-2 0

0

0 1 2 3 4 5

THD PLUS NOISE vs. INPUT SIGNAL AMPLITUDE AND RESISTIVE LOAD (MAX7 40 3)

TABLE A. THD PLUS NOISE vs. INPUT SIGNALAMPLITUDE TEST CONDITIONS

M A X 7 4 0 0 / 0 3 1 4

AMPLITUDE (Vp-p)

T H D

+ N O I S E ( d B )


RL= 500Ω

RL =1kΩ

RL= 10kΩ

TRACE fIN(Hz)

fC(kHz)

fCLK(kHz)

MEASUREMENTBANDWIDTH (kHz)

A

B

C

2800

2000

1000

14

10

5

1400

1000

500

80

80

80

D 200 1 100 22


-90

-70

-80

-40

-50

-60

-10

-20

-30

0

0 1.00.5 1.5 2.0 2.5 3.0

THD PLUS NOISE vs. INPUT SIGNALAMPLITUDE AND RESISTIVE LOAD (MAX740 4)

M A X 7 4 0 0 t o c

1 6

AMPLITUDE (Vp-p)

T H D

+ N O I S E ( d B )

RL= 10kΩ

RL= 1kΩ

RL= 500Ω


-90

-70

-80

-40

-50

-60

-10

-20

-30

0

0 1.00.5 1.5 2.0 2.5 3.0

THD PLUS NOISE vs. INPUT SIGNALAMPLITUDE (MAX7407 )

M A X 7 4 0 0 t o c

1 7

AMPLITUDE (Vp-p)

T H D

+ N O I S E ( d B )


ABC

D-9 0

-7 0

-8 0

-4 0

-5 0

-6 0

-1 0

-2 0

-3 0

0

0 1.00.5 1.5 2.0 2.5 3.0

THD PLUS NOISE vs. INPUT SIGNALAMPLITUDE AND RESISTIVE LOAD (MAX7 40 7)

M A X X 7 4 0 0 t o c

1 8

AMPLITUDE (Vp-p)

T H D

+ N O I S E ( d B )

RL = 500Ω


RL = 10kΩRL = 1kΩ

-9 0

-7 0

-8 0

-4 0

-5 0

-6 0

-1 0

-2 0

-3 0

0

0 1.00.5 1.5 2.0 2.5 3.0

THD PLUS NOISE vs. INPUT SIGNALAMPLITUDE (MAX7404 )

M A X 7 4 0 0 t o c

1 5

AMPLITUDE (Vp-p)

T H D

+ N O I S E ( d B )

B


CDA

8/18/2019 MAX7400MAX7407


Pin Description

PIN

C om m on Inp ut. B iase d interna lly at m idsup p ly. B ypass externa lly to G N D w ith a 0.1µF c ap ac itor. To ove r-

ride internal biasing , d rive w ith an external supply.C O M1

FUNCTIONNAME

Filter InputIN2

Po sitive Supp ly Inp ut: + 5V for M A X7400/M A X7403, + 3V for M A X7 404 /M A X7 407VD D4

G roundG N D3

O ffset A djust Inp ut. To ad just ou tput offset, b ias O S externally. C on ne ct O S to C O M if no offset ad justm en t isneed ed . R efer to O ffset and C om m on-M od e Inp ut A djustm ent section.O S6

C lock Input. To o verride the internal oscillator, connect to a n e xternal clock; otherw ise, connect an e xternal

capacitor (C O SC) from C LK to G N D to set the internal oscillator freque nc y.C LK8

Shutdow n Inp ut. D rive low to e nable sh utdow n m od e; d rive h igh o r connec t to V D D for norm al op eration. SHDN 7

Filter O utputO U T5

M A X 7 4 0 0 / M A X 7 4 0 3 / M A X 7 4 0 4 / M A X 7 4 0 7


8 _______________________________________________________________________________________


0.96

0.98

0.97

1.00

0.99

1.03

1.02

1.01

1.04

-40 0-20 20 40 60 80 100

NORMALIZED OSCILLATOR FREQUENCYvs. TEMPERATURE

M A X 7 4 0 0 t o C 2 1

TEMPERATURE (°C)

N O R M A L I Z E D

O S C I L L A T O R F R E Q U E N C Y COSC = 390pF

MAX7400MAX7403

MAX7404MAX7407

0.80

0.85

0.90

0.95

1.00

1.05

1.10

1.15

1.20

2.5 3.53.0 4.0 4.5 5.0 5.5

NORMALIZED OSCILLATOR FREQUENCYvs. SUPPLY VOLTAGE

M A X 7 4 0 0 t o c

2 0

SUPPLY VOLTAGE (V)

N O R M

A L I Z E D

O S C I L L A T O R F R E Q U E N C Y COSC = 390pF

MAX7400MAX7403

MAX7404MAX7407

0.1

1

100

10

1000

10,000

0.01 10.1 10 100 1000

INTERNAL OSCILLATOR FREQUENCYvs. COSC CAPACITANCE

M A X 7 4 0 0 t o c

1 9

COSC CAPACITANCE (nF)

O S C I L L A T O R F R E Q U E N C Y ( k H z )

8/18/2019 MAX7400MAX7407


MAX74 0 0 / MAX74 0 3 / MAX74 04 / MAX74 07


_______________________________________________________________________________________ 9

Detailed Description The M A X7400/M A X7403/M A X7404/M A X7407 fam ily of8th-ord er, low p ass filters p rovid es sh arp rolloff w ithg ood stop b an d rejec tion . A ll p arts o p erate w ith a10 0:1 cloc k-to-co rne r freq ue nc y ratio an d a 10 kH zm axim um corner freq uen cy. The se d evices a cce p t asingle + 5V (M A X7400/M A X7403) or + 3V (M A X7404/M A X 74 07 ) sup p ly. Fig ure 1 show s the fun ction al d ia-gram .M ost sw itch ed -ca p acitor filters (S FC s) are d esig nedw ith b iqua dratic section s. Eac h section im plem en ts tw ofiltering p oles, and the sections can b e c ascad ed top rod uce hig her-ord er filters. The ad va ntag e of th isap p roa ch is ea se o f d esig n. H ow ever, this typ e o f

design is highly se nsitive to com ponent variations if anysection’s Q is high. The M A X7400 fam ily uses an a lter-na tive a pproa ch , w hich is to em ulate a passive netw orkusing sw itch ed -ca pac itor integ rators w ith sum m ing an dsca ling . The passive ne tw ork c an be synthesized usingC A D prog ram s or can be found in m any filter b ooks.Fig ure 2 show s a b asic 8th-ord er lad d er ellip tic filterstructure.A sw itched-capacitor filter that em ulates a passive lad -d er filter retains m an y of the sam e a d vantag es. Th ecom ponent se nsitivity of a passive ladd er filter is loww hen com p ared to a cascad ed b iq uad ratic d esign ,bec au se ea ch co m pon en t affects the en tire filter shaperather than a sing le p ole-ze ro pair. In other w ord s, a

m ism atched com ponent in a b iquadratic d esign ha s aconcentrated error on its resp ective p oles, w hile thesam e m ism atch in a lad d er filter de sig n sp read s itserror over all poles.

Elliptic Characteristics Low pass, ellip tic filters such as the M A X7400/M A X7403/M A X7404/M A X7407 provide the steepest possible rolloffw ith freq ue nc y of the four m ost com m on filter typ es(B utterw orth, B essel, C hebyshev, and E llip tic). Figure 3show s the 8th-order ellip tic filter resp onse. The high Qvalue of the poles ne ar the p assb and ed ge com binedw ith the stop ban d zeros allow s for the sharp a tten ua -tion charac te ristic o f e llip tic filte rs, m aking thesedevices ideal for anti-aliasing and post-D A C filtering insing le-sup p ly system s (see the A nti-A liasing and Post- D A C Filtering section).In the freq uency d om ain, the first transm ission ze rocauses the filter’s am plitude to drop to a m inim um level.B eyo nd this zero, the resp onse rises as the freq ue ncyinc reases until the next transm ission zero. Th e stopbandb eg ins a t the stop ban d freq ue nc y, f S . A t frequenciesabove f S, the filter’s g ain does not exceed the gain at f S.

The corner freq uenc y, f C, is d efined as the p oint w herethe filter output attenuation falls just below the passbandripp le. The transition ratio is defined as the ratio of thestop band freq uency to the corner freq uency:

r = f S / f C

The M A X 7400 /M A X74 04 have a transition ratio o f 1.5an d a typ ica l stop b an d rejec tion of 82 d B . Th eM A X7403/M A X7407 have a transition ratio of 1.2 (p ro-vid ing the steep est rolloff) and a typ ical stop b andrejection of 60dB .

2

INTCLOCK

IN

1COM

8CLK SHDN

7

4

5

6

3

VDD

OUT

OS

GND

BIAS

SCF

LOGIC

OFFSETADJ

MAX7400 MAX7403 MAX7404 MAX7407

VDD

Figure 1. F un ction al D iag ram

C10 C11C9

L3 L5 L7

C8 R2C4C2VIN+-

V0

L1R1

C6

Figure 2. 8th-O rder La dder Filter N etw ork

8/18/2019 MAX7400MAX7407


VDD

VSUPPLY

IN

CLK

GND

INPUTOUTPUT

50k

50k

50k

OUT

0.1µF

0.1µF

0.1µFCLOCK

SHDN

COM

OS

MAX7400 MAX7403 MAX7404 MAX7407

Figure 4. O ffset A d justm en t C ircu it

M A X 7 4 0 0 / M A X 7 4 0 3 / M A X 7 4 0 4 / M A X 7 4 0 7


10 ______________________________________________________________________________________

Clock Signal External Clock

T h e M A X 7 4 00 /M A X 7 4 03 /M A X 7 4 04 /M A X 7 4 07 S C F sw ere d esigne d for use w ith externa l cloc ks tha t ha ve a40% to 60% duty cycle. W hen using an external clock,drive C LK w ith a C M O S gate p ow ered from 0 to V D D.Varying the rate of the external clock a d justs the filterco rne r freq ue nc y:

fC = fC LK/ 100

Internal Clock W hen using the internal osc illator, the cap acitance(C O S C) on the C LK p in d eterm ines the osc illator fre-quency:

w here K = 38 for the M A X7400/M A X7403, and K = 34for the M A X7404/M A X7407. S ince the cap acitor valueis in p icofarads, m inim ize the stray capacitance a t C LKso that it does not affect the internal osc illator frequen-cy. Varying the rate of the internal osc illator ad justs thefilter’s c orner frequency b y a 100:1 clock-to-corner fre-q uency ratio. For exa m p le, an internal osc illator fre-qu enc y o f 100 kH z prod uces a nom ina l co rnerfreq uency of 1kH z.

Input Impedancevs. Clock Frequencies

The M A X7400/M A X7403/M A X7404/M A X7407’s inputim p edance is e ffectively that of a sw itched-cap ac itorresistor and is inverse ly p roportional to frequency. The

inp ut im ped ance determ ined by the follow ing eq ua tionrep resen ts the averag e inp ut im p ed an ce , sinc e theinput current is not continuous. A s a rule, use a d rive rw ith an output source im ped ance less than 10% of thefilter’s input im pedance. Estim ate the input im pedanceof the filter using the follow ing form ula:

w here f C LK= clock freq uency and C IN = 0.85p F.

Low-Power Shutdown Mode Th ese d evice s fea ture a shutdow n m od e tha t is ac tivat-ed by d riving SHDN low . P lacing the filter in shutdow nm od e red uc es the sup p ly curren t to 0 .2µ A (typ ) an dp laces the outp ut of the filter into a hig h-im p ed ancestate. For norm al operation, d rive SHDN high or con-nect to V D D.

Applications Information Offset and Common-Mode

Input Adjustment The voltag e a t C O M sets the com m on-m od e inp ut volt-age and is internally b iased at m idsupp ly b y a resistor-d ivid er. B yp ass C O M w ith a 0.1µ F ca p ac itor an dco nnec t O S to C O M . Fo r ap p lica tions req uiring offsetad justm ent or D C level shifting , app ly a n external b iasvo ltag e throug h a resistor-d ivid er netw ork to O S , asshow n in Figure 4 . (N ote: D o not leave O S unconnect-ed.) The output voltage is represented by the follow ingeq uation:

VO U T= (V IN - V C O M) + V O S

Zf CINC LK IN

( )( )

Ω =⋅

1

f (kH z) =K 10

CO S C3

O SC

⋅ ; C in pFO S C

PASSBAND STOPBAND

G A I N

( d B )

FREQUENCYfC fS

fS

fC

fSfC

TRANSITION RATIO =

RIPPLE

Figure 3 . E llip tic Filter R esp onse

8/18/2019 MAX7400MAX7407


MAX74 0 0 / MAX74 0 3 / MAX74 04 / MAX74 07


______________________________________________________________________________________ 11

w ith V C O M= VD D / 2 (typ ical), and w here (V IN - V C O M)

is low pass filtered by the S C F, and V O S is added at theou tp ut stag e. S ee the E lectrica l C harac teristics forC O M and O S inp ut voltag e ranges. C hang ing the volt-ag e o n C O M or O S sig nifica ntly from m id sup p lyreduces the filter’s d ynam ic range.

Power Supplies The M A X 7400 /M A X7 403 op erate from a sing le + 5Vsupply. The M A X7 404/M A X7407 operate from a sing le+ 3V supp ly. B ypass V D D to G N D w ith a 0.1µF cap aci-tor. If dual supp lies are required , connect C O M to thesystem ground and G N D to the negative sup p ly. Figure5 show s an exam ple of dua l-sup p ly operation . S ing le-sup p ly an d d ua l-sup p ly p erform an ce are e q uivalen t.For sing le-supp ly or dual-supp ly operation, d rive C LKand SHDN from G N D (V- in dua l-sup p ly op eration) toVD D. For a ± 2.5V supp ly, use the M A X7400 or M A X7 403;for a ± 1.5V supp ly, use M A X7404 or M A X7407. For ± 5Vdua l-sup p ly ap p lica tions, use the M A X291–M A X297.

Input Signal Amplitude Range Th e idea l inp ut signa l ran ge is d eterm ine d by observ-ing th e vo ltag e leve l a t w h ich th e to ta l h a rm o nicdistortion p lus noise (TH D + N ) is m inim ized for a g ivenco rne r freq ue nc y. Th e Typ ica l O p erating C ha rac teristics sho w TH D + N resp on se a s the inp ut sig na l’speak-to-peak am plitud e is varied . These m easurem entsare m ad e w ith O S a nd C O M biased a t m idsup ply.

Anti-Aliasing and Post-DAC Filtering W h e n u sin g th e M A X 7 4 0 0 /M A X 7 4 0 3 /M A X 7 4 0 4 /M A X 7407 for anti-aliasing or p ost-D A C filtering , syn -chronize the D A C and the filter clocks. If the clocks a renot syn chronized , beat frequencies m ay alias into thepassband.The h ig h c lock-to-corner frequency ratio (100:1) alsoeases the req uirem ents of p re- and post-SC F filtering.A t the input, a low pass filter p revents the aliasing of fre-q ue nc ies a rou nd the cloc k freq ue nc y into the p ass -b and . A t the o utp ut, a low p ass filter attenuates thecloc k fee d throu gh.A high clock-to-corner frequency ratio allow s a sim pleR C low pass filter, w ith the cutoff frequency set abovethe S C F corner frequency, to p rovide input anti-aliasingan d rea sona b le ou tput cloc k atten ua tion .

Harmonic Distortion H arm onic d istortion a rises from nonlinearities w ithin thefilter. Such n onlinearities g enerate harm onics w hen apure sine w ave is app lied to the filter input. Tab le 1 liststyp ical harm onic distortion values w ith a 10k Ω load andan inp ut signal of 4V p-p (M A X7400/M A X7403) or 2V p-p(M A X7404/M A X7 407), at TA = + 25°C .

VDD

V+

V-

IN

CLK

GND

INPUTOUTPUTOUT

0.1µF

CLOCK

*DRIVE SHDN TO V- FOR LOW-POWER SHUTDOWN MODE.

SHDN

COM

OS

0.1µF

MAX7400 MAX7403 MAX7404 MAX7407

*

V+

V-

Figure 5. D ua l-Sup p ly O peration

2nd

-88100

TYPICALHARMONIC

DISTORTION (dB)

1

fC(kHz)

-89100

200

1

-84

fIN(Hz)

200

4th3rd 5th

-89500M A X 7 40 0

5 1000

-86-89-82

-88-93-77

500M A X 7 40 3

5 1000

-87-91

FILTER

-81

-91-90-804

VIN(Vp-p)

4

fCLK(kHz)

-85100 1 200

-85500M A X 7 40 4

5 1000

-86-85-82

-84-86-812

-85100 1 200

-86500M A X 7 40 7

5 1000

-86-85-82

-86-85-842

Table 1. Typical Harmonic Distortion

8/18/2019 MAX7400MAX7407


M A X 7 4 0 0 / M A X 7 4 0 3 / M A X 7 4 0 4 / M A X 7 4 0 7


Package Information

S O I C N

. E P S

TRAN SISTO R C O U N T: 1116

Ordering Information (continued) Chip Information

PARTMAX7403 C SAM A X 7 40 3C PAM A X 7403E SA -40°C to + 85°C

0°C to + 70°C0°C to + 70°C

TEMP. RANGE PIN-PACKAGE8 SO8 Plastic D IP8 SO


MAX7404 C SAM A X 7 40 4C PAM A X 7404E SA -40°C to + 85°C

0°C to + 70°C0°C to + 70°C 8 SO

8 Plastic D IP8 SO


MAX7407 C SAM A X 7 40 7C PA

M A X 7407E SA -40°C to + 85°C

0°C to + 70°C0°C to + 70°C 8 SO

8 Plastic D IP

8 SOM A X7407E PA -40°C to + 85°C 8 Plastic D IP

M axim ca nn ot assum e resp on sib ility for use of any circu itry o the r tha n c ircu itry entirely em bod ied in a M axim p rod uc t. N o c ircu it paten t lice nses are im p lied . M axim reserves the right to ch an ge the circu itry a nd sp ec ifica tion s w itho ut notice at any tim e.

12 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600

© 1999 M axim In tegra ted Produc ts P rin ted U SA is a reg iste red tradem ark o f M axim In tegra ted Produc ts.

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