ETC GS3018

Class D Preamp with
Anti-Aliasing Network
GS3018 - HYB DATA SHEET
FEATURES
Provisions have been made on the hybrid to allow the
manufacturer to increase or decrease this corner frequency
with the addition of a capacitor. As the class D receiver
utilizes a 100 kHz clock, lower harmonics of the frequency
may feed back into the system and interact with the
incoming signal from the microphone. Capacitors C5 and
C6 have been added to the hybrid to minimize this effect,
known as "aliasing".
• incorporates GR504, 3 stage amplifer chip
• designed to drive class D integrated receivers
• adjustable symmetrical peak clipper for MPO
control
• two low noise inverting preamplifiers
• mid-supply referenced output stage
• anti-aliasing filter network
STANDARD PACKAGING
• Hybrid Typical Dimensions:
0.244 in x 0.102 in x 0.115 in
(6.20 mm x 2.59 mm x 2.92 mm)
DESCRIPTION
The GS3018 contains Gennum's GR504 class D preamplifier
chip, six capacitors and one resistor. Capacitor C1 on the
hybrid, in conjunction with R MIC on the GR504 chip, form a
high pass filter which provides a very well regulated supply
voltage for the microphone. Resistor R1, capacitor C2 and
the output impedance of the microphone (≈ 4 kΩ) also form
a high pass filter with a corner frequency of approximately
240 Hz.
Blocks A and B on the GR504 are low noise inverting
preamplifiers with an open loop voltage gain of typically
50 dB. Typically, the volume control potentiometer would
be placed around block A, and block B used either as a
Gain Trim stage or as a Telecoil amplifier. The voltage gain
of these two blocks is determined by the ratio of the input
resistance to the value of the feedback resistor. With
100 kΩ potentiometer used as a feedback resistor for both
stages, block A would have a maximum gain of 20 dB, and
block B a gain of 26 dB.
Block C is a mid-supply referenced output stage designed
to drive class D receivers. It is typically capable of 670 mV
peak to peak output voltage swing and 14 dB of MPO
(Maximum Power Output) control with a 10 kΩ MPO
potentiometer. The gain of the output stage is fixed at
typically 16 dB.
RMIC
VMIC
C2
RP1
C2
R1
47n
10k
2
-A
2
-B
RP2
5k
4
C5
1n8
5
- C
10 OUT
C4
68n
C6
1n8
GR504
1
MGND
9 VB
3
C1
4µ7
IN
4
1
2A
10
8
9
7
6
3
C3
68n
5
6
VC1
VC2
7
13
BRIN BIN
GS3018
14
8 15 16 12 11
BOUT1 BOUT2 C3 CIN MPO GND
All resistors in ohms, all capacitors
in farads unless otherwise stated.
FUNCTIONAL BLOCK DIAGRAM
Revision Date: May 1998
Document No. 521 - 09 - 03
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: [email protected]
ABSOLUTE MAXIMUM RATINGS
PAD CONNECTION
PARAMETER
VALUE / UNITS
Supply Voltage
3 VDC
Power Dissipation
25 mW
Operating Temperature Range
MGND
C2
VC1
VC2
3
4
5
6
BR IN BOUT2
Storage Temperature Range
-20° C to 70° C
CAUTION
CLASS 1 ESD SENSITIVITY
OUT
9
10
15
16
11
C3
CIN
8
7
-10° C to 40° C
IN
VB
GND
2
1
14
13
12
VMIC
BOUT1
BIN
MPO
ELECTRICAL CHARACTERISTICS
Conditions: Frequency = 1 kHz, Temperature = 25°C, Supply Voltage VB = 1.3 V
PARAMETER
Supply Current
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
I AMP
165
240
315
µA
VBIAS
500
580
650
mV
40
44
48
dB
550
612
670
mV
dB
STAGE A AND B
Input Bias Voltage
Gain (pin 2 to pin 8)
GAINAB
VIN = -60dBV
OUTPUT STAGE
Input Bias Voltage
Voltage Gain (pin 15 to pin 10)
Maximum Output Level
MPO Range
Gain at 10 kHz
VCIN
GAINC
VIN = -50dBV, RMPO = 0
14
16
18
MPO
VIN = -22dBV, RMPO = 0
-14.5
-12.5
-10.5
12
14
16
dB
0
4.5
9.0
dB
∆MPO
GAIN 10kHz
VIN = -22dBV, RMPO = 10K
VIN = -55dBV, RMPO = 0
All parameters and switches remain as shown in the Test Circuit unless otherwise stated in CONDITIONS column
V QX - quiescent (unbias) voltage measured on the pin, (nothing connected to the pin). VPX - actual voltage measured on the pin at given
condition (X is pin number).
521 - 09 - 03
2
dBV
1.3VDC
RMIC
1
C1
4µ7
9
RP1
C2
R1
47n
10k
2
VIN
4
3
2
-B
-A
5
- C
3kHz
10
C4
68n
RP2
5k
4
C5
1n8
50k
C6
1n8
GR504
1
9
10
2A
8
6
7
3
C3
68n
6
5
7
14
13
15
8
GS3018
16 12
11
RMPO
VIN
1kHz
100k
100k
0µ1
All resistors in ohms, all capacitors
in farads unless otherwise stated.
Fig. 1 Production Test Circuit
1.3VDC
RMIC
4
1
MIC
9
3
C1
4µ7
RP1
C2
R1
47n
10k
2
2
-A
-B
5
- C
10
RP2
5k
4
C5
1n8
C4
68n
C6
1n8
GR504
1
2A
10
8
9
CLASS D
INTEGRATED
RECEIVER
1µ
6
7
3
C3
68n
6
5
RVC
100k
7
14
13
8
15
16 12
GS3018
11
RMPO
10k
RGT
100k
All resistors in ohms, all capacitors
in farads unless otherwise stated.
Fig. 2 Typical Hearing Instrument Application
3
521 - 09 - 03
1.3VDC
RMIC
4
1
MIC
9
3
C1
4µ7
RP1
C2
R1
47n
10k
2
-A
2
-B
5
- C
C4
68n
RP2
C6
1n8
GR504
1
2A
10
8
9
RCVR
10
5k
4
C5
1n8
1µ
6
7
3
C3
68n
6
5
7
14
13
15
8
RVC
GS3018
16 12
RMPO
10k
11
100k
All resistors in ohms, all capacitors
in farads unless otherwise stated.
TELECOIL
Fig. 3 Typical Application Circuit
VOLUME
CONTROL
BATTERY
-
+
1µ
4
3
MIC
5
6
7
8
9
15
16
10
+
REC
11
2
+
1
14
13
12
RMPO
RGT
Fig. 4 Typical Assembly Diagram
521 - 09 - 03
4
1.3VDC
RMIC
4
1
a
S1
RP1
C2
R1
47n
10k
2
b
4
-B
-A
2
CEXT
3k9
9
3
C1
4µ7
C5
1n8
10
C4
68n
RP2
5k
C6
1n8
GR504
2A
1
VIN
1kHz
VOUT
5
- C
9
10
8
6
7
50k
3
C3
68n
6
5
7
14
13
RFA
RFB
100k
100k
8
GS3018
16 12
15
11
RMPO
All resistors in ohms, all capacitors
in farads unless otherwise stated.
Fig. 5 Characterization Circuit
(used to generate typical curves)
-10
-10
RMPO=0
-20
OUTPUT (dBV)
RFA=47k
-30
OUTPUT (dBV)
-15
RFA=100k
-20
-40
RFA=22k
-50
RFA=10k
RMPO=3k3
-25
RMPO=10k
-30
-35
-60
-40
-70
-45
-80
-140 -130 -120
-110
-100
-90
-80
-70
-60
-50
-50
-40
-100
-90
-80
INPUT (dBV)
-70
-60
-50
-40
INPUT (dBV)
Fig. 7 Maximum Power Output vs RMPO
Fig. 6 Input vs Output (RMPO = 0)
10
2
47nF(S1=a)
9
-2
7
-10
THD (%)
RELATIVE OUTPUT (dB)
8
-6
CEXT=22nF(S1=b)
-14
CEXT=10nF(S1=b)
-18
6
5
4
3
-22
2
-26
-30
20
1
100
1k
10k
0
-100
20k
FREQUENCY (Hz)
-96
-92
-88
-84
-80
-76
-72
-68
INPUT (dBV)
Fig. 8 Frequency Response vs CIN
Fig. 9 THD vs Input (RFA=100k, R MPO=0)
5
521 - 09 - 03
0.244
(6.20)
GS3018
0.102
(2.59)
XXXXXX
0.125 (3.18)
MAX
4
3
6
5
8
9
10
15
16
11
13
12
7
2
C1
1
14
Dimension units are in inches.
Dimensions in parenthesis are in millimetres converted from inches and include minor round-off errors.
1.0000 inches = 25.400 mm.
Smallest pad 0.020 x 0.020 (0.51 x 0.51).
Largest pad 0.034 x 0.020 (0.86 x 0.51).
Dimension tolerances ±0.003" (± 0.08) unless otherwise specified.
Pad numbers and capacitor numbers for illustration only.
XXXXXX - work order number.
This hybrid is designed for point to point manual soldering.
Fig. 9 Hybrid Layout and Dimensions
DOCUMENT IDENTIFICATION: 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.
REVISION NOTES:
Updated to Data sheet
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 March 1994 Gennum Corporation.
All rights reserved.
521 - 09 - 03
6
Printed in Canada.