thinSTAXTM PACKAGING
Hybrid Typical Dimensions:
0.205 x 0.110 x 0.060in.
(5.21 x 2.79 x 1.52mm)
PRELIMINARY DATA SHEET
BLOCK DIAGRAM
DESCRIPTION
The GA3205 is a multi-memory hybrid that, with the addition of
two microphones, can be used to produce a directional
response in any hearing aid. The four available memories can
be programmed to include any of the 4 modes of operation: 1
mic omnidirectional, 2 mic omnidirectional, directional, and
directional equalized. The variable time delay of the circuit
gives it the flexibility to offer a wide range of directivity patterns
(ie. cardioid to hypercardioid) for microphone port spacings
from 6mm to 13mm. Variable low frequency equalization
gives the flexibility to trade-off between bass response and
noise performance.
Calibration software automatically configures the hybrid for
the desired directivity pattern and adjusts the gain trim resistors
to compensate for micropohone sensitivity mismatches
enabling maximum directivity.
The GA3205 hybrid code programmed into the GP523 is "2".
FEATURES
4 different modes of operation:
directional
directional equalized
1 mic omnidirectional
2 mic omnidirectional
allows for mic port spacing from 6mm to 13mm
calibration software automatically trims out mic
sensitivity mismatches
variable time delay/directivity pattern
4 memories
variable low frequency equalization (0 to 20dB)
small package size
compatible with all hearing aids
Revision Date: September 1999
FRONT
MIC
REAR
MIC
GND1
GND2
OUT
VB
C4
100n
C1
200n
C2
200n
10k
15k5
3k9
GA3205
10k
15k5
R7
460k
36k
R8
92k
R3
185k
R6
185k
C6
4n4
R9
18k
R4
184k
C5
1n2
R2 45k5
R5
92K
16k
11k
25k
6k
6k
26k
26k
24k
SW
GP523
8
10
C3
100n
VREG1 VREG2
SDA
MS
All resistors in ohms, all capacitors in farads unless otherwise stated.
6
7
12
1
4
2
5
11
-D
-B
-A
-C
REGULATOR
Document No. 522 - 18 - 01
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
GA3205
F
RONT
W
AVE
TM
Multi-Microphone
Hybrid - GA3205
2
522 - 18 - 01
GA3205
ABSOLUTE MAXIMUM RATINGS
PARAMETER
VALUE
Supply Voltage
2VDC
Power Dissipation
25mW
Operating Temperature
-10 to + 40
C
Storage Temperature
-20 to +70
C
PAD CONNECTION
ELECTRICAL CHARACTERISTICS
Conditions: Temperature 25
o
C, Frequency = 1 kHz. R1 - Tap 15; R2 - Tap 15; R3 - Tap 0; R4 - Tap 0; R5 - Tap 0; R6 - Tap 0; R7 - Tap 3; R8 - Tap 14
(All conditions and parameters remain as shown in test circuit unless stated in condition column)
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k
1
2
3
4
5
6
7
8
9
10
11
12
13
GND2
GND1
FRONT
MIC
REAR
MIC
V
B
OUT
V
REG2
V
REG1
MS
SDA
CAUTION
ELECTROSTATIC
SENSITIVE DEVICES
DO NOT OPEN PACKAGES OR HANDLE
EXCEPT AT A STATIC-FREE WORKSTATION
522 - 18 - 01
3
GA3205
12
Any AC-Coupled
Amplifier or Signal
Processor
GND1
GND2
FRONT
MIC
REAR
MIC
VB
C4
100n
C1
200n
C2
200n
10k
15k5
3k9
GA3205
10k
15k5
R7
460k
36k
R8
92k
R3
185k
R6
185k
C6
4n4
R9
18k
R4
184k
C5
1n2
R2 45k5
R5
92K
16k
11k
25k
6k
6k
26k
26k
24k
SW
GP523
8
10
C3
100n
VREG1
VREG2
SDA
MS
All resistors in ohms, all capacitors in farads unless otherwise stated.
6
7
12
1
4
2
5
11
-D
-B
-A
-C
REGULATOR
Fig. 1 Production Test Circuit
Fig. 2 Typical Hearing Instrument Application
3k9
3k9
GND1
GND2
200n
10k
V
OUT
FRONT
MIC
REAR
MIC
VB
C4
100n
C1
200n
C2
200n
10k
15k5
3k9
GA3205
10k
15k5
R7
460k
36k
R8
92k
R3
185k
R6
185k
C6
4n4
R9
18k
R4
184k
C5
1n2
R2 45k5
R5
92K
16k
11k
25k
6k
6k
26k
26k
24k
SW
GP523
8
10
C3
100n
VREG1 VREG2
SDA
MS
All resistors in ohms, all capacitors in farads unless otherwise stated.
6
7
12
1
4
2
5
11
-D
-B
-A
-C
REGULATOR
522 - 18 - 01
5
GA3205
Fig. 5 Frequency Response
for Different R6 Tap Settings
(Front Channel)
Fig. 6 Stage C Time Delay Adjustment
Fig. 7 Frequency Response
(Rear Channel)
Fig. 8 I/O Transfer Function for
Front and Rear Channels
Fig. 9 THD and Noise vs Frequency
Fig. 10 THD and Noise vs Input Level
FREQUENCY (Hz)
GAIN (dB)
R6 - Tap 15
R6 - Tap 0
20
15
10
5
0
-5
-10
20 100 1k 10k 20k
V
IN
= -40 dBV
R4 RESISTOR TAPS
DELA
Y OF ST
AGE C (
s)
35
30
25
20
15
10
5
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
R8 - Tap 0
R8 - Tap 14
R8 - Tap 24
R3 & R4 - Tap 0
R3 & R4 - Tap 15
V
IN
= -40 dBV
-15
-10
-5
0
5
100
1k
10k
FREQUENCY (Hz)
GAIN (dB)
FRONT CHANNEL: R7 - Tap 0
R7 - Tap 24
REAR CHANNEL: R8 - Tap 0
R8 - Tap 24
f = 1 kHz
-100
-90
-80
-70
-60
-50
-40
-30
-20
INPUT LEVEL (dBV)
-90
-80
-70
-60
-50
-40
-30
-20
OUTPUT LEVEL (dBV)
FRONT CHANNEL
REAR CHANNEL
V
IN
= -40 dBV
0.01
0.1
1
THD & NOISE (%)
100
1k
10k
FREQUENCY (Hz)
f = 1 kHz
FRONT CHANNEL
REAR CHANNEL
0.01
0.1
10
THD & NOISE (%)
1
-80
-70
-60
-50
-40
-30
-20
INPUT LEVEL (dBV)
TYPICAL PERFORMANCE CURVES
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