March 1997

ML2008

µP Compatible Logarithmic Gain/Attenuator

FEATURES

s

Low noise

0dBrnc max with +24dB gain

s

Low harmonic distortion

–60dB max

s

Gain range

–24 to +24dB

s

Resolution

0.1dB steps

s

Flat frequency response

±0.05dB from 0.3-4kHz

±0.10dB from 0.1-20kHz

s

Low supply current

4mA max from

±5V supplies

s

TTL/CMOS compatible digital interface

s

ML2008 is designed to interface to an 8-bit data bus;

ML2009 to 16-bit data bus

GENERAL DESCRIPTION

The ML2008 and ML2009 are digitally controlled

logarithmic gain/attenuators with a range of –24 to +24dB

in 0.1dB steps.

Easy interface to microprocessors is provided by an input

latch and control signals consisting of chip select and

write.

The interface for gain setting of the ML2008 is by an 8-bit

data word, while the ML2009 is designed to interface to a

16-bit data bus with a single write operation by hard-

wiring the gain/attenuation pin or LSB pin. The ML2008

can be power downed by the microprocessor utilizing a

bit in the second write operation.

Absolute gain accuracy is 0.05dB max over supply

tolerance of

±10% and temperature range.

These CMOS logarithmic gain/attenuators are designed for

* This Part Is End Of Life As Of August 1, 2000

a wide variety of applications in telecom, audio, sonar or

** This Part Is Obsolete

general purpose function generation.

BLOCK DIAGRAM

+

–

+

–

+

–

RESISTORS/

SWITCHES

RESISTORS/

SWITCHES

GND

AGND

COARSE

FINE

BUFFER

16

16

+5

–5

DECODERS

WR

CS

A0

REGISTER 0

REGISTER 1

8

1

1

PDN

D1–D8

8

+

–

+

–

+

–

RESISTORS/

SWITCHES

RESISTORS/

SWITCHES

GND

AGND

COARSE

FINE

BUFFER

16

16

+5

–5

DECODERS

REGISTER 0

9

D0–D8

9

WR

CS

ML2008

ML2009

*

1