Class A
Compression Amplifier
LD511 DATA SHEET
FEATURES
•
64 dB typical electrical gain
•
0.94 V
DC
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
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 V
DC
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
Ω.
STANDARD PACKAGING
• 10 pin MICROpac
• 10 pin MINIpac
• 10 pin PLID
®
• 10 pin SLT
• Chip (59 x 59 mils)
Au Bump
A OUT
10
B IN
1
VB
6
VOLTAGE
REGULATOR
V
REG
7
20K
9
3
A IN
R
IN
-A
10K
35K
-B
B OUT
R
E
5
RECTIFIER
8
4
2
AGC
C
AGC
All resistors in ohms, all capacitors
in farads unless otherwise stated
GND
R
E
BLOCK DIAGRAM
Revision Date: January 2001
500 - 32 - 11
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
GENNUM [ GENNUM CORPORATION ]
