Low Current, Peak Limiting
Class A Amplifier
LT505 DATA SHEET
FEATURES
• amplifier current typically 53
µ
A
• transducer current typically 210
µ
A
• Schottky diodes provide peak limiting
• low parts count
• gain 74dB typically with 1.3 V supply
STANDARD PACKAGING
• 8 Pin MICROPAC
• 8 Pin MINIPAC
• 8 Pin PLID
®
• 8 Pin SLT
• chip ( 56 x 55 mils)
Au Bump
DESCRIPTION
The LT505 is a low current, low voltage monolithic integrated
circuit amplifier. It is comprised of an operational amplifier
driving a single transistor class A output stage with open
collector. Also included is a pair of complementary Schottky
diodes which, when shunted across the load, provide the
capability for symmetrical peak clipping.
The input stage is biased by an external 200 kΩ resistor. It is
important that this resistor be
±1%
tolerance for optimum
performance. An internal negative feedback loop ensures a
stable operating point for the output stage over the designed
operating voltage. Because of the lowered idle current,
trimming the output current with the use of a single external
resistor is not recommended for the LT505.
The typical gain for this IC is 74 Due to low power consumption
dB.
this part is the perfect choice for the output
stage of class A hearing instruments.
BLOCK DIAGRAM
V
MIC
8
2.2K
O/P
3
6
I/P
V
B
4
MPO
8
1
2.2 K
EQUIVALENT CIRCUIT
4
1
+
_
33K
100
5
200
6
3
27 K
100
33 K
2
200
7
GND
R
E
U.S. Patent No. 4,034,306
Patented in other countries
2
5
7
R
VC
All resistors in ohms, all capacitors in
µF
unless otherwise stated
Revision Date: June 1994
Document No. 500 - 45 - 9
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 ]
