LP502 [GENNUM]
Low Distortion AGC Compression Amplifier; 低失真AGC放大器压缩
| 型号： | LP502 |
| 厂家： | 
GENNUM CORPORATION |
| 描述： | Low Distortion AGC Compression Amplifier |
| 文件： | 总4页 (文件大小：106K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Low Distortion AGC
Compression Amplifier
LP502 CUSTOM DATA SHEET
FEATURES
By using RGT (see test circuit) to vary the value of this current
controlled resistance, the amplifier gain and compression
threshold can be controlled over a range of 60 dB.
• adjustable gain from 0 to 60 dB
• 0.94 V DC voltage regulator on-chip
• attack time fixed at less than 1 ms
• release time adjustable from 40 to 500 ms
• low input referred noise 1.2 µV
• <1 % distortion at 10 mVRMS output
• operates from 1.05 to 3 VDC
The AGC current is derived from a full wave rectifier driven by
a differential amplifier. The attack time of the AGC circuit is
fixed at less than 1 ms. The release time is adjustable from
40 to 500 ms by selecting the value of an external capacitor
(C3).
Internally, a series shunt voltage regulator produces a 0.94 V
DC regulated output voltage. This provides a bias for electret
microphones and permits circuit operations over a wide range
of supply voltages, 1.05 to 3 VDC for LP502 without any
degradation of electrical performances.
STANDARD PACKAGING
• 8 pin MICROpac
• 8 pin PLID ®
As compared to the LD502, the LP502 incorporates an
additional diode between the amplifier output and the AGC
filter point. This “attack diode” is responsible for precharging
the AGC filter point, which enables quicker attack time and
helps to reduce the gain overshoot (during transients) that is
observed in the LD502 with certain combinations of AGC input
coupling and filter capacitors. However, with this diode
connected, some level of AGC is always present with higher
output levels even when the AGC input is disconnected.
Therefore the LP502 cannot be used as a “pure” linear
amplifier.
• Chip (64 x 62 mils)
Au Bump
DESCRIPTION
The LP502 is a compression (AGC) preamplifier that consists
of a single-ended input inverting amplifier, with an internal
current controlled resistance connected between input and
output.
VB
GAIN SET
4
7
2
VOLTAGE
REGULATOR
VREG
1
A OUT
AMPLIFIER
A IN
3
6
FULL WAVE
RECTIFIER
AGC IN
8
5
AGC FILTER
GND
BLOCK DIAGRAM
Patented 1985
Canada 1183580
Patent Pending Europe 83.300836.0
USA 4506169 Japan 58-06886
Document No. HP2802-1
GENNUM CORPORATION P.O. Box 489, Stn A, Burlington, Ontario, Canada L7R 3Y3 tel. (905) 632-2996 fax: (905) 632-5946
Gennum Japan Corporation:C-101 Miyamae Village, 2–10–42 Miyamae, Suginami–ku, Tokyo 168-0081, Japan tel. (03) 3334-7700 fax (03) 3247-8839
ABSOLUTE MAXIMUM RATINGS
PIN CONNECTION
PARAMETER
VALUE/UNITS
3 V DC
Supply Voltage
5
4
AGC FILTER
AGC IN
VB
GAIN SET
A OUT
VREG
Power Dissipation
25 mW
Operating Temperature Range
Storage Temperature Range
-10°C to 50° C
-20°C to 70° C
1
8
GND
A IN
CAUTION
CLASS 1 ESD SENSITIVITY
ELECTRICAL CHARACTERISTICS
Conditions: Frequency = 1 kHz, Temperature = 25°C, Supply Voltage VB = 1.3 VDC
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
VOUT
Gain
AV
VOUT = 11.0 mV,
38
41
46
dB
20 Log (
)
VIN
Output Level
VOHIGH
THD
VIN = 6.32 mV, S1 closed
VOUT = 11.0 mV
7.5
12
1
15.5
2.9
2.2
2.2
8
mV
%
Distortion -Linear
- AGC
-
VIN = 6.32mV, S1 closed
-
-
1
%
Input Referred Noise
Compression Function Ratio
Total Amplifier Current
Regulated Voltage
Supply Rejection
IRN
S2 closed,NFB 0.2 to 10 kHz at 12 dB/Oct
VIN = 0.1 to 6.32 mV, S1 closed
1.2
5
µV
2
dB
µA
IAMP
VREG
PSRR
160
0.890
51
310
0.940
60
380
0.990
-
VDC
dB
All parameters and switches remain as shown in Test Circuit unless otherwise stated in "Conditions" column
ITOT
RGT
130k
VB= 1.3 VDC
7
4
2
VOLTAGE
REGULATOR
C5
1.0
C1
0.47
1
3
6
AMP
VOUT
RTH
0Ω
RS= 3.5k
S2
S1
RL
10K
FULL WAVE
RECTIFIER
C4
0.1
RM
33K
8
5
C2
1.0
VIN
C3
1.0
All resistors in ohms, all capacitors in microfarads unless otherwise stated
Fig. 1 Test Circuit
HP2802-1
2
GAIN TRIM
VB=1.3 VDC
4.7
4.7
500k
4
7
LP502
4
6
1
LC549
VOLTAGE
REGULATOR
2
1
V
4.7
C =10k
0.1
5
0.1
RS 3.9k
2
R =400
L
TYP
AMP
3
0.1
8
FULL WAVE
RECTIFIER
6
3
7
5
8
NC
0.047
0.1-1.0
All resistors in ohms, all capacitors in microfarads unless otherwise stated
Fig. 2 LP502/LC549Hearing Instrument Application
GAIN TRIM
LP502
VB=1.3 VDC
500k
8
4
7
4
LE507
BK1606
Z=1k
1
7
VOLTAGE
REGULATOR
2
1
25k
4.7
13.5k
2
18k
0.1
0.1
0.1
RS 3.9k
33k
2k
AMP
3
5
0.1
FULL WAVE
RECTIFIER
VC
10k
6
6
3
5
8
R =33
E
0.47
All resistors in ohms, all capacitors in
microfarads unless otherwise stated
Fig. 3 LP502/LE507 Hearing Instrument Application
HP2802-1
3
100
10
1
100
10
RTH=50kΩ
RTH=22kΩ
RTH=10kΩ
RGT=130kΩ
RGT=82kΩ
RGT=68kΩ
RGT=47kΩ
RTH=0kΩ
1
0.1
0.01
0.01
0.1
1.0
10
0.1
1.0
10
INPUT (mV)
INPUT (mV)
Fig. 4 I/O Characteristics at
Various RTH Values
Fig. 5 I/O Characteristics at
Various RGT Values
4
2
100
CS=0.22 µF
0
CS=0.1 µF
-2
RTH=0
-4
-6
VB=3 VDC
-8
10
CS=0.047 µF
CS=0.033 µF
-10
-12
-14
-16
-18
-20
VB=1.3 VDC
0.1
0.01
20
200
2K
20k
0.1
1.0
10
FREQUENCY (Hz)
INPUT (mV)
Fig. 6 Effects of Supply Voltage
Variation
Fig. 7 Frequency Response at
Various CS Values
4.0
3.0
2.0
1.0
0.0
DOCUMENT
IDENTIFICATION
PRODUCT PROPOSAL
This data has been compiled for market investigation purposes
only, and does not constitute an offer for sale.
ADVANCE INFORMATION NOTE
This product is in development phase and specifications are
subject to change without notice. Gennum reserves the right to
remove the product at any time. Listing the product does not
constitute an offer for sale.
0.0
5.0
10.0
15.0
20.0
25.0
OUTPUT (mV)
Fig. 8 Total Harmonic Distortion
vs Output Level
PRELIMINARY DATA SHEET
The product is in a preproduction phase and specifications are
subject to change without notice.
DATA SHEET
The product is in production. Gennum reserves the right to make
changes at any time to improve reliability, function or design, in
order to provide the best product possible.
Gennum Corporation assumes no responsibility for the use of any circuits described herein and makes no representations that they are free from patent infringement.
© Copyright August 1997 Gennum Corporation. All rights reserved. Printed in Canada.
HP2802-1
4
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