1

Features

4 Digitally Controlled Amplifiers

15 Gain/Attenuation Steps

3 Amplifiers, with a ± 3dB Range

in 0.43dB Steps

1 'Volume' Amplifier, with a

± 14dB Range in 2dB Steps

FX019

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 during

development, production/calibration and operation.

Applications include:

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

equipment by an Intelligent ATE without manual

intervention – eg. Deviation, Microphone and L/S

Levels, 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 FX019 is a low-power, single 5-volt CMOS

device available in plastic DIL and Small Outline

(S.O.I.C.) SMD package versions.

Publication D/019/4 December 1995

8-Bit Serial Data Control

Output Mute Function

Audio and Data Gain Control

Applications

Telecoms, Radio and Industrial

Applications

CML Semiconductor Products

FX019

2

3

3

3

4

4

SERIAL DATA

INPUT

LOAD/LATCH

LOAD/LATCH

CHIP SELECT

1

1

2

2

Ch1

Ch2

Ch4

Ch3

V

DD

V

BIAS

SERIAL CLOCK

INPUT

8-BIT SERIAL DATA INPUT

AND

LINE DECODERS

CONTROLLED AUDIO OUTPUT LINES

VOLUME

Digitally Controlled

Quad Amplifier Array

PRODUCT INFORMATION

The FX019 Digitally Adjustable Amplifier Array is

available to replace trimmer potentiometers and

volume controls in Cellular, PMR, Telephony and

Communications applications where d.c., voice or

data signals need adjustment.

The FX019 is a single-chip LSI consisting of four

digitally controlled amplifier stages, each with 15

distinct gain/attenuation steps. Control of each

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

Three 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 suggested for

volume control applications. Each amplifier includes a

16th 'Off' state which when applied, mutes the output

audio from that channel. This array uses a Chip

Select input to select one of two FX019s in a system.

Fig.1 Functional Block Diagram