Digitally-Programmed, Dual

2nd-Order Continuous Lowpass Filter

MAX270/MAX271

19-3701; Rev 2; 1/12

Devices are available in a lead(Pb)-free/RoHS-compliant package.

Specify lead-free by adding a plus (+) to the part number when

ordering.

Ordering Information

Pin Configurations

Typical Operating Circuit

General Description

The MAX270/MAX271 are digitally-programmed, dual

second-order continuous-time lowpass filters. Their typi-

cal dynamic range of 96dB surpasses most switched

capacitor filters which require additional filtering to

remove clock noise. The MAX270/MAX271 are ideal for

anti-aliasing and DAC smoothing applications and can

be cascaded for higher-order responses.

The two filter sections are independently programmable

by either microprocessor (FP) control or pin strapping.

Cutoff frequencies in the 1kHz to 25kHz range can be

selected.

The MAX270 has an on-board, uncommitted op amp,

while the MAX271 has an internal track-and-hold (T/H).

Applications

Lowpass Filtering

Anti-Aliasing Filter

Output Smoothing

Low-Noise Applications

Anti-Aliasing and Track-and-Hold (MAX271)

Features

S

Continuous-Time Filtering - No Clock Required

S

Dual 2nd-Order Lowpass Filters

S

Sections Independently Programmable: 1kHz to

25kHz

S

96dB Dynamic Range

S

No External Components

S

Cascadable for Higher Order

S

Low-Power Shutdown Mode

S

Track-and-Hold (MAX271)

V+

+5V

-5V

FILTER A

ANTI-ALIASING

INA

OUTA

IN

V-

GND

FILTER B

ANTI-ALIASING

AO

CS

D0-D6

µP OR PIN-STRAP CONTROL

OUTB

INB

DSB

DAC

A/D WITH

T/H

OUT

WR

MAX270

OUTA

SHDN

D4

1

2

20

19

OP OUT

V+

D6

D5

OP IN

PDIP/SO(W)

TOP VIEW

3

4

18

17

INB

OUTB

D0

5

6

16

15

INA

V-

D2

D1

D3

7

8

14

13

GND

Pin Configurations

continued at end

of data sheet.

A0

912

WR

CS

10

11

MAX270

PART

TEMP RANGE

PIN-PACKAGE

MAX270CPP

0NC to +70NC

20 PDIP

MAX270CWP

0NC to +70NC

20 Wide SO

MAX270EPP

-40NC to +85NC

20 PDIP

MAX270EWP

-40NC to +85NC

20 Wide SO

MAX271CNG

0NC to +70NC

20 PDIP

MAX271CWG

0NC to +70NC

20 Wide SO

MAX271ENG

-40NC to +85NC

20 PDIP

MAX271EWG

-40NC to +85NC

20 Wide SO

For pricing, delivery, and ordering information, please contact Maxim Direct

at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.