ACF2101BUE4 Datasheet, PDF (1/16 Pages) Texas Instruments – Low Noise, Dual SWITCHED INTEGRATOR

®
ACF2101
FPO
Low Noise, Dual
SWITCHED INTEGRATOR
FEATURES
q INCLUDES INTEGRATION CAPACITOR,
RESET AND HOLD SWITCHES, AND
OUTPUT MULTIPLEXER
q LOW NOISE: 10µVrms
q LOW CHARGE TRANSFER: 0.1pC
q WIDE DYNAMIC RANGE: 120dB
q LOW BIAS CURRENT: 100fA
APPLICATIONS
q CURRENT TO VOLTAGE CONVERSION
q PHOTODIODE INTEGRATOR
q CURRENT MEASUREMENT
q CHARGE MEASUREMENT
q CT SCANNER FRONT END
q MEDICAL, SCIENTIFIC, AND INDUSTRIAL
INSTRUMENTATION
DESCRIPTION
The ACF2101 is a dual switched integrator for preci-
sion applications. Each channel can convert an input
current to an output voltage by integration, using either
an internal or external capacitor. Included on the chip
are precision 100pF integration capacitors, hold and
reset switches, and output multiplexers.
As a complete circuit on a single chip, the ACF2101
eliminates many of the problems commonly encoun-
tered in discrete designs, such as leakage current errors
and noise pickup. The integrating approach can pro-
vide lower noise than conventional transimpedance
amplifier designs and also eliminates the need for high
performance, high value feedback resistors.
The extremely low bias current and low noise of the
ACF2101’s Difet ^® amplifiers, along with active la-
ser trimming of both offset and drift, assure precision
current to voltage conversion.
Although designed for +5V, –15V supplies, the
ACF2101 can be operated on supplies up to ±18VDC.
It is available in both 24-pin plastic DIP and SOIC
packages.
Difet^® Burr-Brown Corp.
Cap A
In A
Sw In A
Com A
Cap B
In B
Sw In B
Com B
Reset
A
B
Hold
A
B
C_INTERNAL
100pF
Reset
Hold
Select
A
B
A
Select
Hold
C_INTERNAL
100pF
Reset
B
Select
AB
V+ Gnd V–
Out A
Sw Out A
Sw Com A
Out B
Sw Out B
Sw Com B
SBFS003
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© 1990 Burr-Brown Corporation
PDS-1078D
Printed in U.S.A. September, 1994