Gennum Corporation GS3018 Datasheet
FEATURES
• 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
Class D Preamp with
Anti-Aliasing Network
GS3018 - HYB DATA SHEET
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".
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
on the GR504 chip, form a
MIC
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.
R
V
1
MIC
C1
4µ7
R1
C2
IN
C2
2
4
47n
10k
3
2
MIC
GR504
-
A
5k
2A110
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.
4
R
P1
-
B
9
C
-
R
P2
8
6
7
C5
1n8
5
C4
68n
C6
1n8
V
B
9
OUT
10
MGND
Revision Date: May 1998
3
All resistors in ohms, all capacitors
in farads unless otherwise stated.
GENNUM CORPORATION P.O. Box 489, Stn. A, Burlington, Ontario, Canada L7R 3Y3 tel. +1 (905) 632-2996
C3
68n
5
VC1 VC2
6
7
B
RIN
14
13
B
OUT1
B
OUT2
B
IN
8
15
C3
16 11
12
C
MPO
IN
FUNCTIONAL BLOCK DIAGRAM
Web Site: www.gennum.com E-mail: hipinfo@gennum.com
GS3018
GND
Document No. 521 - 09 - 03
ABSOLUTE MAXIMUM RATINGS
PAD CONNECTION
PARAMETER VALUE / UNITS
MGND
C2
VC1
VC2
BR
B
IN
OUT2VB OUT
Supply Voltage 3 VDC
9
9
Power Dissipation 25 mW
Operating Temperature Range -10° C to 40° C
Storage Temperature Range -20° C to 70° C
CAUTION
CLASS 1 ESD SENSITIVITY
IN
3
V
2
1
MIC
6
5
4
8
7
16
15
C
B
OUT1
C3
14
IN
13
B
IN
ELECTRICAL CHARACTERISTICS
Conditions: Frequency = 1 kHz, Temperature = 25°C, Supply Voltage V
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Supply Current I
AMP
STAGE A AND B
Input Bias Voltage V
BIAS
Gain (pin 2 to pin 8) GAINAB VIN = -60dBV 40 44 48 dB
OUTPUT STAGE
Input Bias Voltage V
CIN
Voltage Gain (pin 15 to pin 10) GAINC VIN = -50dBV, R
Maximum Output Level MPO VIN = -22dBV, R
MPO Range ∆MPO V
IN
Gain at 10 kHz GAIN10kHz VIN = -55dBV, R
= 1.3 V
B
= -22dBV, R
165 240 315 µA
500 580 650 mV
550 612 670 mV
= 0 14 16 18 dB
MPO
= 0 -14.5 -12.5 -10.5 dBV
MPO
= 10K 12 14 16 dB
MPO
= 0 0 4.5 9.0 dB
MPO
10
11
12
MPO
GND
All parameters and switches remain as shown in the Test Circuit unless otherwise stated in CONDITIONS column
V
- quiescent (unbias) voltage measured on the pin, (nothing connected to the pin). V
QX
condition (X is pin number).
521 - 09 - 03
2
- actual voltage measured on the pin at given
PX
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