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General Description

The MAX7401/MAX7405 8th-order, lowpass, Bessel,

switched-capacitor filters (SCFs) operate from a single

+5V (MAX7401) or +3V (MAX7405) supply. These

devices draw only 2mA of supply current and allow cor-

ner frequencies from 1Hz to 5kHz, making them ideal

for low-power post-DAC filtering and anti-aliasing appli-

cations. They feature a shutdown mode that reduces

supply current to 0.2µA.

Two clocking options are available on these devices:

self-clocking (through the use of an external capacitor)

or external clocking for tighter corner-frequency control.

An offset adjust pin allows for adjustment of the DC out-

put level.

The MAX7401/MAX7405 Bessel filters provide low over-

shoot and fast settling. Their fixed response simplifies

the design task to selecting a clock frequency.

Applications

ADC Anti-Aliasing

CT2 Base Stations

Post-DAC Filtering

Speech Processing

Air-Bag Electronics

Features

o 8th-Order, Lowpass Bessel Filters

o Low Noise and Distortion: -82dB THD + Noise

o Clock-Tunable Corner Frequency (1Hz to 5kHz)

o 100:1 Clock-to-Corner Ratio

o Single-Supply Operation

+5V (MAX7401)

+3V (MAX7405)

o Low Power

2mA (Operating Mode)

0.2µA (Shutdown Mode)

o Available in 8-Pin SO/DIP Packages

o Low Output Offset: ±5mV

8th-Order, Lowpass, Bessel,

Switched-Capacitor Filters

________________________________________________________________

Maxim Integrated Products

1

OS

OUT

1

2

8

7

CLK

SHDN

IN

GND

COM

SO/DIP

TOP VIEW

3

4

6

5

MAX7401

MAX7405

IN

CLK

OUT

GND

INPUT

0.1

µF

0.1

µF

CLOCK

SHDN

OUTPUT

COM

OS

MAX7401

MAX7405

Typical Operating Circuit

19-4788; Rev 1; 6/99

Pin Configuration

Ordering Information

PART

MAX7401CPA

MAX7401ESA

MAX7401EPA

-40°C to +85°C

-40°C to +85°C

0°C to +70°C

TEMP. RANGE

PIN-PACKAGE

8 Plastic DIP

8 SO

8 Plastic DIP

MAX7405CSA

MAX7405CPA

MAX7405ESA

MAX7405EPA

-40°C to +85°C

-40°C to +85°C

0°C to +70°C

0°C to +70°C

8 SO

8 Plastic DIP

8 SO

8 Plastic DIP

MAX7401CSA

0°C to +70°C

8 SO