
LD511 DATA SHEET
Class A
Compression Amplifier
DESCRIPTION
The LD511 is a Class A compression amplifier which can
operate over a range of DC battery voltages from 1.1 V
to 2.4 V. A voltage regulator, which is independent of supply
voltage variations, is on-chip to supply a stable 0.94 VDC bias
to the amplifier circuitry and to the microphone.
The LD511, in compression, has approximately 15 dB of
threshold adjustment by varying
R
TH
(see application circuit)
and a compression function ratio of
∞ : 1.
Minimum attack and release times are fixed at 7 ms and 40 ms
respectively and they can be adjusted simultaneously by
changing the filter capacitor on pin 8, although the ratio of
attack to release time is kept constant.
The output stage bias can be set to accommodate different
receiver impedances by changing the value of
R
E
. The
voltage across
R
E
(pin 2 to ground) is a constant 27 mV so the
bias current is 27 mV divided by the total value of
R
E
in parallel
with 500
.
FEATURES
64 dB typical electrical gain
0.94 VDC voltage regulator
7 ms attack time, 40 ms release time
15 dB threshold adjustment
low noise and distortion
compression ratio
∞ : 1
0.3 kHz - 6 kHz frequency response
STANDARD PACKAGING
10 pin MICROpac
10 pin MINIpac
10 pin PLID
10 pin SLT
Chip (59 x 59 mils)
Au Bump
BLOCK DIAGRAM
VOLTAGE
REGULATOR
10K
35K
RECTIFIER
B OUT
AGC
GND
CAGC
A IN
VREG
A OUT
B IN
VB
9
7
10
1
6
3
5
2
4
8
20K
RE
- B
- A
RIN
RE
500 - 32 - 11
All resistors in ohms, all capacitors
in farads unless otherwise stated
Revision Date: January 2001
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