LT505 Datasheet, PDF (1/2 Pages) List of Unclassifed Manufacturers – Low Current, Peak Limiting Class A Amplifier

FEATURES
• amplifier current typically 53 µA
• transducer current typically 210 µA
• Schottky diodes provide peak limiting
• low parts count
• gain 74dB typically with 1.3 V supply
STANDARD PACKAGING
• 8 Pin PLID^®
• chip ( 56 x 55 mils)
Low Current, Peak Limiting
Class A Amplifier
LT505 DATA SHEET
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 74dB. Due to low power consumption
this part is the perfect choice for the output
stage of class A hearing instruments.
BLOCK DIAGRAM
EQUIVALENT CIRCUIT
6
I/P
100
5
R_VC
V_MIC
V_B
MPO
8
8
4
1
2.2K
O/P
3
+
6
_
33K
200
7
2
5
GND
R_E
All resistors in ohms, all capacitors in µF unless otherwise stated
2.2 K
27 K
U.S. Patent No. 4,034,306
100
33 K
Patented in other countries
4
1
3
2
200
7
Revision Date: January 2001
Document No. 500 - 45 - 10
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