Class A Amplifier with 3
Independent Gain Blocks
LC508 DATA SHEET
FEATURES
•
1
µ
V input referred noise
•
1.0 to 5 VDC operating range
•
73 dB typical gain (adjustable)
•
0.28 to 2.0 mA range of transducer current
•
1% electrical distortion
•
the first and second blocks, or second and third
blocks can be DC coupled
•
100 Hz to 50 kHz frequency response
•
suitable for active filtering
STANDARD PACKAGING
• 10 PIN MICROpac
•10 pin PLID
®
• 10 pin SLT
• Chip (52 x 49 mils)
DESCRIPTION
The LC508 is a 10 pin Class A amplifier utilizing Gennum's
proprietary low voltage bipolar JFET technology. It consists of
3 single ended, low noise inverting gain blocks. The first two
blocks have a typical open loop gain of 50 dB. The closed loop
gain is set by the ratio of the feedback resistor to the source
impedance. The third block is an open collector output stage
with the bias being set by
R
E
and
V
RE
at pin 8 which is 54 mV.
Typically, the gain of the first two blocks is set to 25 dB each,
with the third block at 23 dB, giving a total gain of 73 dB.
Gain trim can be accomplished with the use of a feedback
resistor on the first block, while the volume control is used as
the feedback control on the second block. This gives a volume
control range greater than 40 dB.
V
B
6
5
MIC
R
MIC
V
A IN
4
7
- A
- B
- C
8
R
E
C OUT
R
E
2
A OUT
3
B IN
10
B OUT
9
C IN
1
GND
BLOCK DIAGRAM
Revision Date: January 2001
Document No. 500 - 61 - 12
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
GENNUM [ GENNUM CORPORATION ]
