Datasheet
1
®
INA121
International Airport Industrial Park • Mailing Address: PO Box 11400, Tucson, AZ 85734 • Street Address: 6730 S. Tucson Blvd., Tucson, AZ 85706 • Tel: (520) 746-1111 • Twx: 910-952-1111
Internet: http://www.burr-brown.com/ • FAXLine: (800) 548-6133 (US/Canada Only) • Cable: BBRCORP • Telex: 066-6491 • FAX: (520) 889-1510 • Immediate Product Info: (800) 548-6132
®
INA121
INA121
INA121
©1997 Burr-Brown Corporation PDS-1412A Printed in U.S.A. May, 1998
FEATURES
● LOW BIAS CURRENT: ±4pA
● LOW QUIESCENT CURRENT:
±450µA
● LOW INPUT OFFSET VOLTAGE:
±200µV
● LOW INPUT OFFSET DRIFT:
±2µV/°C
● LOW INPUT NOISE:
20nV/√Hz at f = 1kHz (G =100)
● HIGH CMR: 106dB
● WIDE SUPPLY RANGE:
±2.25V to ±18V
● LOW NONLINEARITY ERROR: 0.001% max
● INPUT PROTECTION TO
±40V
● 8-PIN DIP AND SO-8 SURFACE MOUNT
FET-Input, Low Power
INSTRUMENTATION AMPLIFIER
DESCRIPTION
The INA121 is a FET-input, low power instrumenta-
tion amplifier offering excellent accuracy. Its versatile
three-op amp design and very small size make it ideal
for a variety of general purpose applications. Low bias
current (±4pA) allows use with high impedance
sources.
Gain can be set from 1V to 10,000V/V with a single
external resistor. Internal input protection can with-
stand up to ±40V without damage.
The INA121 is laser-trimmed for very low offset
voltage (±200µV), low offset drift (±2µV/°C), and
high common-mode rejection (106dB at G = 100). It
operates on power supplies as low as ±2.25V (+4.5V),
allowing use in battery operated and single 5V sys-
tems. Quiescent current is only 450µA.
Package options include 8-pin plastic DIP and SO-8
surface mount. All are specified for the –40°C to
+85°C industrial temperature range.
APPLICATIONS
● LOW-LEVEL TRANSDUCER AMPLIFIERS
Bridge, RTD, Thermocouple
● PHYSIOLOGICAL AMPLIFIERS
ECG, EEG, EMG, Respiratory
● HIGH IMPEDANCE TRANSDUCERS
● CAPACITIVE SENSORS
● MULTI-CHANNEL DATA ACQUISITION
● PORTABLE, BATTERY OPERATED SYSTEMS
● GENERAL PURPOSE INSTRUMENTATION
A
1
A
2
A
3
6
40kΩ40kΩ
40kΩ40kΩ
7
4
3
8
1
2
V
IN
V
IN
R
G
V+
V–
INA121
Ref
V
O
G = 1 +
50kΩ
R
G
–
+
5
Over-Voltage
Protection
25kΩ
25kΩ
Over-Voltage
Protection
SBOS078