鈭?/div>
Hz at 10kHz
PLASTIC DIP and SOIC PACKAGE
APPLICATIONS
q
PHOTODETECTOR PREAMP
q
q
q
q
q
CHROMATOGRAPHY
ELECTROMETER AMPLIFIERS
MASS SPECTROMETER
pH PROBE AMPLIFIER
ION GAGE MEASUREMENT
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
廬
) inputs, this mono-
lithic amplifier achieves a high performance level.
Substrate
8
7
V+
Difet
fabrication eliminates isolation-junction leakage
current鈥攖he 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鈥攅ven with the surface-mount package version.
OPA129 is available in 8-pin DIP and SO-8 packages,
specified for operation from 鈥?0擄C to +85擄C.
鈥揑n
2
3
+In
Noise-Free
Cascode
6
Output
30k鈩?/div>
30k鈩?/div>
5
V鈥?/div>
Simplified Circuit
Difet
廬
Burr-Brown Corp.
International Airport Industrial Park 鈥?Mailing Address: PO Box 11400
Tel: (520) 746-1111 鈥?Twx: 910-952-1111 鈥?Cable: BBRCORP 鈥?/div>
鈥?Tucson, AZ 85734 鈥?Street Address: 6730 S. Tucson Blvd. 鈥?Tucson, AZ 85706
Telex: 066-6491 鈥?FAX: (520) 889-1510 鈥?Immediate Product Info: (800) 548-6132
漏
1994 Burr-Brown Corporation
PDS-1195A
Printed in U.S.A. July, 1994
next