3

Maxim Integrated

Digitally-Programmed, Dual

2nd-Order Continuous Lowpass Filter

MAX270/MAX271

ELECTRICAL CHARACTERISTICS (continued)

(V+ = +5V, V- = -5V; TA = +25NC, unless otherwise noted.)

Note 1: All internal amplifiers limited to 2MHz bandwidth.

Note 2: Only filter A tested for these parameters.

Note 3: Spurious-Free Dynamic Range is the ratio of the fundamental to the largest of any harmonic or noise spur in dB.

Note 4: Includes T/H propagation delays. With 5kω, parallel 100pF load.

Note 5: ±2V input step settling 0.1% with 5kω parallel 100pF load.

Note 6: T/H pin toggled at sampling rate, 50% duty cycle.

Note 7: THD and SFDR specifications for T/H include contributions from filter.

Note 8:

Digital pins include SHDN, WR, CS, A0, D0–D6 (MAX270) and SHDN, T/H, A/B, WR, T/H EN, CS, A0, A1, D0–D6, T/H

(MAX271).

Note 9: Input of uncommitted op amp disconnected with a 5kω feedback resistor from input to output.

Note 10: WR, CS, A0, D0–D6 held at +5V; VSHDN = 0V (MAX270). WR, CS, A0, A1, D0–D6, T/H, T/H, A/B, T/H, MODE held at

+5V; VSHDN = 0V (MAX271).

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

DYNAMIC FILTER CHARACTERISTICS (MAX270)

Total Harmonic Distortion

THD

fC code = 44 (2.01kHz typ), VIN = 3.5VP-P at

390.625Hz (Notes 2 and 3)

-70

dB

Signal Noise Plus Distortion

SINAD

73

Spurious-Free Dynamic Range

SFDR

70

UNCOMMITTED AMPLIFIER (MAX270)

Slew Rate

1.2

V/Fs

Bandwidth

2

MHz

TRACK AND HOLD (MAX271)

Hold Settling Time

To 0.1% (Note 4)

500

ns

Acquisition Time

To 0.1% (Note 5)

1.8

F

s

Hold Step

1

mV

Droop Rate

TA = TMIN to TMAX

30

F

V/Fs

Offset Voltage at T/H OUT

Includes filter offset

-6

+6

mV

T/H OUT Disabled Output Leakage

Current

TA = TMIN to TMAX, VT/H = 0V (Track Mode)

-10

+10

F

A

Total Harmonic Distortion

THD

fC code = 44 (2.01kHz typ), VIN = 3.5VP-P at

390.625Hz, sampling rate = 50kHz

(Notes 2, 6, 7)

-70

dB

Spurious-Free Dynamic Range

SFDR

70

DIGITAL INPUTS

Digital Input High Voltage

TA = TMIN to TMAX (Note 8)

2.4

V

Digital Input Low Voltage

0.8

Digital Input Current

TA = TMIN to TMAX, digital input held at Q5V,

includes MODE (MAX271)(Note 8)

-1

+1

F

A

POWER REQUIREMENTS

Supply Voltage Range

Q

2.375

to Q8

V

Supply Current

TA = TMIN to TMAX (Note 9)

6.5

mA

Shutdown Supply Current

TA = TMIN to TMAX (Note 10)

15

F

A

Power-Supply Rejection Ratio at

1kHz

PSRR

fC code = 0 (1kHz typ), V+ = 5VDC +

10mVP-P at 1kHz

30

dB