FEATURES
LOW BIAS CURRENT: ±4pA
LOW QUIESCENT CURRENT: ±450mA
LOW INPUT OFFSET VOLTAGE: ±200mV
LOW INPUT OFFSET DRIFT: ±2mV/°C
LOW INPUT NOISE:
20nV/ÖHz 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

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

DESCRIPTION
The INA121 is a FET-input, low power instrumentation
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 withstand
up to ±40V without damage.
The INA121 is laser-trimmed for very low offset
voltage (±200mV), low offset drift (±2mV/°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 systems.
Quiescent current is only 450mA.
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.