DATA SHEET

AGC-O with Active Low Cut Filter

in a CIC Size Hybrid - GS3044

FEATURES

•

CIC suitable package size

•

low distortion compression limiting

•

38dB maximum system gain, adjustable over a

38dB range

•

output compression threshold, adjustable over

16dB range

•

2nd order active low cut filter adjustable from 530Hz

to 2.0kHz

•

designed to drive a class D integrated receiver

•

averaging detector

•

flexibility to add high cut filter

STANDARD PACKAGING

Hybrid typical dimensions:

0.180 x 0.110 x 0.070 in.

(4.57 x 2.79 x 1.78 mm)

DESCRIPTION

The GS3044 CIC hybrid features AGC-O capability for low

distortion output limiting with an active low cut filter in a

package size suitable for CIC instruments. The circuit consists

of an AGC preamplifier and output stage, capable of driving

a class D integrated receiver. The compression control circuit,

connected between the input and output of the AGC

preamplifier, varies the current controlled resistance. It

operates with an 8:1 compression ratio and uses an averaging

detector with a time constant of 270ms, selected to provide

optimal sound quality over a full range of sound and listening

environments. The actual attack and release times are typically

40ms and 150ms respectively when the circuit is fully in the

compression region of operation (measured times vary

depending on gain and threshold settings).

The system gain, compression control and filter corner

frequency can be adjusted by choosing three independent

resistors or 100k trimmers. Maximum system gain is 38dB. It

can be adjusted within a 38dB range. The output compression

threshold can be adjusted within a 16dB range. The filter's

corner frequency can be adjusted from 530Hz to 2kHz.

BLOCK DIAGRAM

Revision Date: March 2000

C2

0

µ1

C5

0

µ1

C7

0

µ15

C8

33n

12k

48k

VB

REGULATOR

48k

-A

RECT.

B

8:1

COMPRESSION

CONTROL

C6

22n

-F

C1

15n

C3

6n8

C4

10n

10k

80k

800

IN

GND

OUT

GS3044

R1 = 0

10

1

4

5

6

7

8

9

3

2

All resistors in ohms, all capacitors

in farad, unless otherwidse stated.

GENNUM CORPORATION P.O. Box 489, Stn. A, Burlington, Ontario, Canada L7R 3Y3 tel. +1 (905) 632-2996

Web Site: www.gennum.com

E-mail: hipinfo@gennum.com

Document No. 521 - 90 - 02