Datasheet

TC7650
DS21463C-page 2  2001-2012 Microchip Technology Inc.
General Description
The TC7650 CMOS chopper stabilized operational
amplifier practically removes offset voltage error terms
from system error calculations. The 5V maximum V
OS
specification, for example, represents a 15 times
improvement over the industry standard OP07E. The
50nV/°C offset drift specification is over 25 times lower
than the OP07E. The increased performance elimi-
nates V
OS
trim procedures, periodic potentiometer
adjustment and the reliability problems caused by dam-
aged trimmers.
The TC7650 performance advantages are achieved
without the additional manufacturing complexity and
cost incurred with laser or "zener zap" V
OS
trim tech-
niques.
The TC7650 nulling scheme corrects both DC V
OS
errors and V
OS
drift errors with temperature. A nulling
amplifier alternately corrects its own V
OS
errors and the
main amplifier V
OS
error. Offset nulling voltages are
stored on two user supplied external capacitors. The
capacitors connect to the internal amplifier V
OS
null
points. The main amplifier input signal is never
switched. Switching spikes are not present at the
TC7650 output.
The 14-pin dual-in-line package (DIP) has an external
oscillator input to drive the nulling circuitry for optimum
noise performance. Both the 8 and 14-pin DIPs have
an output voltage clamp circuit to minimize overload
recovery time.
Functional Block Diagram
TC7650
Null
NULL
Inputs
Output
Clamp
Output
BB
A
C
A
C
B
For 8-Pin DIP, connect to V
ss
Null
Amplifier
Main
Amplifier
Output Clamp
Circuit
Intermod
Compensation
Oscillator
AB
INT/EXT
EXT CLK IN
CLK OUT
14-Pin DIP Only
BA
*C
RETN
*