CIC suitable package size
8:1 compression ratio
38 dB maximum system gain,
adjustable over a 38 dB range
output compression threshold,
adjustable over 16 dB range
designed to drive a class D integrated receiver
averaging detector
STANDARD PACKAGING
Hybrid typical dimensions:
0.162 in x 0.094 in x 0.070 in
(4.11 mm x 2.39 mm x 1.78 mm)
C1
0
1
C2
0
1
C3
0
15
OUT
IN
GND
C4
33n
C5
22n
GS3026
12k
48k
V
B
REG.
48k
-A
RECT.
B
8:1
COMPRESSION
CONTROL
V
B
Rvc
VREG
R
TH
1
2
3
5
6
4
7
GS3026 - DATA SHEET
AGC-O in a CIC Size Hybrid
FEATURES
DESCRIPTION
The GS3026 CIC hybrid features AGC-O capability for low
distortion output limiting and offers a package size suitable
for CIC instruments. The circuit consists of a newly designed
AGC preamplifier and output stage, capable of driving the
class D integrated receiver. The compression control
circuit varies the current controlled resistance, connected
between the input and output of the AGC preamplifier. The
compression circuit operates with an 8:1 compression
ratio and uses an averaging detector with a time constant
of 270 ms, selected to provide optimal sound quality over
the full range of sound and listening environments. The
actual attack and release times are typically 40 ms and 150
ms respectively when the circuit is fully in the compression
region of operation (measured times will vary depending
on gain and threshold settings).
The system gain and compression control can be adjusted
by the choice of two independent resistors. Maximum
system gain is 38 dB and it can be adjusted within a 38 dB
range. The output compression threshold can be adjusted
within a 16 dB range.
BLOCK DIAGRAM
All resistors in ohms, all capacitors in farads unless otherwise stated.
Revision Date: July 1998
Document No. 521 - 71 - 02
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
521 - 71 - 02
3026
2
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Hybrid Current
I
AMP
-
165
240
A
Minimum Voltage
V
B
-
1.1
-
V
Total Harmonic Distortion
THD
V
IN
=-60dBV
-
0.5
1
%
Input Referred Noise
IRN
A weighted
-
2
2.5
V
RMS
Total System Gain
A
V
V
IN
=-70dBV
35
38
41
dB
Regulator Voltage
V
REG
890
950
1000
mV
Power Supply Rejection Ratio
PSRR
49
57
-
dB
AGC
Maximum Threshold
TH
MAX
V
IN
=-60dBV
-43
-41
-39
dBV
(Output Referred)
Note 2
Minimum Threshold
TH
MIN
V
IN
=-70dBV R
TH
= 200k
-59
-57
-55
dBV
(Output Referred)
Note 2
VC Gain Range
A
VC
R
VC
=200k
to 0
35
38
41
dB
Compression Ratio High Threshold
CMP-H
V
IN
=-60dBV to -30dBV R
TH
=0
8
9.0
10
ratio
Compression Ratio Low Threshold
CMP-L
V
IN
=-70dBV to -40dBV R
TH
=200k
6.5
7.3
9
ratio
Stage A Gain
A
A
V
IN
=-70dBV
24
27
30
dB
Compression Gain Range
A
RANGE
R
TH
=200k; Note 1
47
50
55
dB
AGC Time Constant
AGC
-
270
-
ms
OUTPUT STAGE
Gain
A
B
9
11
13
dB
Output Resistance
20
24
28
k
All parameters and switches remain as shown in the Test Circuit unless otherwise stated in CONDITIONS column.
Note 1
.
A
RANGE
= A
A
-A
A
[V
IN
= -20dBV]
2
. Measured at output of Stage A
ABSOLUTE MAXIMUM RATINGS
PARAMETER
VALUE / UNITS
Supply Voltage
3 VDC
Power Dissipation
25 mW
Operating Temperature Range
-10
C to 40
C
Storage Temperature Range
-20
C to 70
C
PAD CONNECTION
Conditions: Frequency = 1 kHz, Temperature = 25
C, Supply Voltage V
B
= 1.3 V
ELECTRICAL CHARACTERISTICS
1
V
B
3
V
REG
2
IN
4
R
VC
5
OUT
6
R
TH
7
GND
CAUTION
CLASS 1 ESD SENSITIVITY
3026
521 - 71 - 02
3
Fig. 1 Production Test Circuit
Fig. 2 Typical Hearing Instrument Application
All resistors in ohms, all capacitors in farads unless otherwise stated.
All resistors in ohms, all capacitors in farads unless otherwise stated.
C1
0
1
C2
0
1
2
2
C3
0
15
C4
33n
C5
22n
GS3026
12k
48k
V
B
REG.
48k
-A
RECT.
B
8:1
COMPRESSION
CONTROL
Any Knowles
class D
integrated
receiver
Any Knowles
or Microtronic
Microphone
V
B
V
B
Rvc
R
TH
2
1
2
3
5
6
4
7
C1
0
1
C2
0
1
C3
0
15
C4
33n
C5
22n
GS3026
12k
3k9
48k
50k
V
B
V
IN
REG.
48k
-A
RECT.
V
OUT
B
8:1
COMPRESSION
CONTROL
V
B
Rvc=200k
R
TH
=0
1
2
3
5
6
4
7
521 - 71 - 02
3026
4
Fig. 4 Characterization Circuit (used to generate Typical Curves)
Fig. 3 Typical Hearing Instrument Assembly Diagram
All resistors in ohms, all capacitors in farads unless otherwise stated.
- +
REC
BATTERY
MIC
R
VC
R
TH
+
+
1
3
2
4
5
6
2
2
7
C1
0
1
C2
0
1
C3
0
15
C4
33n
C5
22n
GS3026
12k
3k9
PINK NOISE
GENERATOR
or 1kHz for I/O
48k
50k
V
B
REG.
48k
-A
RECT.
V
OUT
B
8:1
COMPRESSION
CONTROL
1.3V
Rvc=200k
R
TH
=200k
4
1
2
3
5
6
4
7
3026
521 - 71 - 02
5
100
1000
500
400
300
200
-140
-120
-100
-80
-60
-40
-20
0
-80
-75
-70
-65
-60
-55
-50
-45
-40
-35
-30
-25
-20
-15
-140
-120
-100
-80
-60
-40 -20 0
0.1
1
10
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
0.04
100
-140
-120
-100
-80
-60
-40
-20
0
1000
500
400
300
200
10
15
20
25
30
35
40
100
1k
10k
20k
20
-95
-85
-75
-65
-55
-45
-35
-25
-15
-140
-120
-100
-80
-60
-40
-20
0
OUTPUT (dBV)
INPUT (dBV)
Fig. 5 Input vs Output Volume Control Settings
GAIN (dB)
FREQUENCY (kHz)
Fig. 7 Frequency Response vs R
TH
AMPLIFIER CURRENT (
A)
Fig. 8 Amplifier Current vs R
VC
INPUT (dBV)
AMPLIFIER CURRENT (
A)
Fig. 10 THD vs Input
THD (%)
R
VC
=200k
100k
50k
25k
10k
3.3k
0
R
TH
= 0
V
IN
=1kHz
OUTPUT (dBV)
INPUT (dBV)
Fig. 6 Input vs Output Threshold Settings
R
TH
= 0
50k
200k
R
TH
= 0
R
TH
=50k
R
TH
=200k
R
VC
= 200k
V
IN
=-70dBV
R
TH
= 0
V
IN
=1kHz
R
VC
= 200k
INPUT (dBV)
Fig. 9 Amplifier Current vs R
TH
V
IN
=1kHz
R
VC
=200k
INPUT (dBV)
V
IN
=1kHz
R
VC
=200k
R
TH
= 200k
R
TH
=0
R
TH
= 200
50k
0
R
VC
= 0
V
IN
=1kHz
R
VC
= 200k
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