OPA129 Datasheet, PDF (1/7 Pages) Burr-Brown (TI) – Ultra-Low Bias Current Difet OPERATIONAL AMPLIFIER

®
OPA129
Ultra-Low Bias Current Difet^®
OPERATIONAL AMPLIFIER
FEATURES
q ULTRA-LOW BIAS CURRENT: 100fA max
q LOW OFFSET: 2mV max
q LOW DRIFT: 10µV/°C max
q HIGH OPEN-LOOP GAIN: 94dB min
q LOW NOISE: 15nV/√Hz at 10kHz
q PLASTIC DIP and SOIC PACKAGE
DESCRIPTION
The OPA129 is an ultra-low bias current mono-
lithic operational amplifier offered in an 8-pin PDIP
and SO-8 package. Using advanced geometry
dielectrically-isolated FET (Difet^®) inputs, this mono-
lithic amplifier achieves a high performance level.
Difet fabrication eliminates isolation-junction leakage
current—the main contributor to input bias current
with conventional monolithic FETs. This reduces
input bias current by a factor of 10 to 100. Very low
input bias current can be achieved without resorting to
small-geometry FETs or CMOS designs which can
suffer from much larger offset voltage, voltage noise,
drift, and poor power supply rejection.
The OPA129's special pinout eliminates leakage cur-
rent that occurs with other op amps. Pins 1 and 4 have
no internal connection, allowing circuit board guard
traces—even with the surface-mount package version.
OPA129 is available in 8-pin DIP and SO-8 packages,
specified for operation from –40°C to +85°C.
Difet^® Burr-Brown Corp.
APPLICATIONS
q PHOTODETECTOR PREAMP
q CHROMATOGRAPHY
q ELECTROMETER AMPLIFIERS
q MASS SPECTROMETER
q pH PROBE AMPLIFIER
q ION GAGE MEASUREMENT
Substrate
8
7
V+
–In
2
3
+In
Noise-Free
Cascode
30kΩ
30kΩ
6
Output
5
V–
Simplified Circuit
International Airport Industrial Park • Mailing Address: PO Box 11400 • Tucson, AZ 85734 • Street Address: 6730 S. Tucson Blvd. • Tucson, AZ 85706
Tel: [phone] • Twx: 910-952-1111 • Cable: BBRCORP • Telex: 066-6491 • FAX: [phone] • Immediate Product Info: [phone]
©_{1994 Burr-Brown Corporation}
PDS-1195A
Printed in U.S.A. July, 1994