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CML Semiconductor Products

PRODUCT INFORMATION

FX009A

Features/Applications

8 Digitally Controlled Low-Noise

Amplifiers

15 Gain/Attenuation Steps

7 Trimmers, with a

± 3dB Range in

0.43dB Steps

1 'Volume' Trimmer, with a

± 14dB

Range in 2.0dB Steps

Brief Description

This product replaces the need for manual trimming of

audible signals by using the host microprocessor to

digitally control the set-up of all audio levels.

Applications include:

(i) Control, adjustment and set-up of communications

equipment by an Intelligent ATE without manual

intervention – eg. Deviation, Microphone and L/S

Level, Rx Audio Level etc.

(ii) Automatic Dynamic Compensation of drift caused

by variations in temperature, linearity, etc.

(iii)Fully automated servicing and re-alignment.

The FX009A is a low-power, single 5-volt CMOS

device available in both 24-pin DIL and SMD package

versions.

The FX009A Digitally Adjustable Amplifier Array is

intended to replace trimmer potentiometers and volume

controls in Cellular, PMR, Telephony and

Communications applications where d.c., voice or data

signals need adjustment.

The FX009A is a low-noise single-chip LSI consisting

eight digitally controlled amplifier stages, each with 15

distinct gain/attenuation steps. Control of each

individual amplifier is by an 8-bit serial data stream.

Seven of the amplifier stages offer a +/-3dB range in

steps of 0.43dB, whilst the remaining amplifier offers a

+/-14dB range in steps of 2dB, and is intended for

volume control applications. Each amplifier includes a

16th 'Mute' state which sets the output to bias (V

and powersaves the entire section. Minimum current

drain may be achieved by muting all eight sections.

Publication D/009A/3 July 1994

Low-Noise Digitally Controlled

Amplifier Array

8-Bit Serial Data Control

Output Mute/Powersave Function

Audio and Data Gain Control

Applications

Cellular, PMR, PABX Applications

FX009A

Fig.1 Functional Block Diagram

8 - BIT

SERIAL DATA INPUT

AND

LINE DECODERS

12

345

67

8

SERIAL DATA INPUT

LOAD/LATCH

1

2

3

4

8

7

6

16-LINE STEP CONTROLS TO AMPLIFIERS 1 to 8

5

43

2

1

5

6

7

Ch1

Ch2

Ch3

Ch4

Ch5

Ch6

Ch7

Ch8

V

DD

V

BIAS

CONTROLLED AUDIO OUTPUT LINES

8 - VOLUME

SERIAL CLOCK INPUT

LOAD/LATCH

V

SS

*

OUTPUT MUTE - POWERSAVE

*

*

*

*

*

*

*

V

BIAS

V

BIAS

V

BIAS

V

BIAS

V

BIAS

V

BIAS

V

BIAS

V

BIAS

16