Class A Amplifier with
2 Independent Gain Blocks
LP508 DATA SHEET
FEATURES
•
1
µ
V input referred noise
•
1.0 to 5 VDC operating range
•
61 dB typical gain (adjustable)
•
0.28 to 2.0 mA range of transducer current
•
1 % electrical distortion
•
the first and second blocks can be DC coupled
•
4.0 k
Ω
microphone decoupling resistor, on-chip
•
100 Hz to 50 kHz frequency response
•
volume control range >40 dB
STANDARD PACKAGING
•
•
•
•
•
8 pin MICROpac
8 pin MINIpac
8 pin PLID
®
8 pin SLT
Chip (59 x 53 mils)
Au Bump
DESCRIPTION
The LP508 is an 8 pin Class A amplifier utilizing Gennum's
proprietary low voltage bipolar JFET technology. It consists of
2 single ended, low noise inverting gain blocks. The first block
has a typical open loop gain of 50 dB, with the closed loop gain
set by the ratio of the feedback resistor to the the source
impedance. The second block has the output transistor bias
set by
R
E
and
V
RE
at pin 7 which is 27 mV.
Typically, the gain of the first block is set to 29 dB, with the
second block at 32 dB, giving a total gain of 61 dB.
V
B
5
V
MIC
4
R
MIC
18K
3
A IN
6
-
A
-
B
7
R
E
1
A OUT
8
B IN
2
GND
B OUT
R
E
BLOCK DIAGRAM
Revision Date: June 1994
Document No. 500 - 71 - 8
GENNUM CORPORATION P.O. Box 489, Stn A, Burlington, Ontario, Canada L7R 3Y3
Japan Branch: A-302, M i yamae Vi l l age, 2–10–42 M i yamae, Suginami–ku, Tokyo 168, Japan
tel. (905) 632-2996 fax: (905) 632-5946
tel. (03) 3334-7700
fax (03) 3247-8839
GENNUM [ GENNUM CORPORATION ]
