1 Features
• Zero cross amplifier for 1.7 V to 5.5 V applications
• High gain-bandwidth product: 20 MHz
• Fast slew-rate: 33 V/μs typical
• Fast 0.01% settling: 200 ns typical for 2 V step
• Low input offset voltage: ±150 μV typical
• Low noise floor: 5.5 nV/√Hz typical at 10 kHz
• High output current: ±110 mA typical ISC at 5.5 V
• Quiescent current: 1.6 mA/ch typical
• Rail-to-rail input and output
• Unity-gain stable
• Drives up to 150 pF without sustained oscillations
• Internal RFI and EMI filtered input pins
• Operating temperature range: –40°C to 125°C

2 Applications
• Amplifier driver for ADCs
• High side current sensing
• Motor rotary encoders
• Transimpedance photodiode amplifiers
• Audio microphone pre-amplifiers
• Ultrasonic transducers

3 Description
The OPAx323 family of op amps includes single
(OPA323), dual (OPA2323), and quad-channel
(OPA4323), low-voltage (1.7 V to 5.5 V), highbandwidth
(20 MHz) amplifiers (op amps) with a zerocrossover
input stage and a rail-to-rail output stage.
The zero-crossover input stage enables OPAx323
to achieve high linearity and low distortion for input
signals with rail-to-rail swing that are typical in
ADC driver applications. Gain-bandwidth of 20 MHz
provides a fast settling response for ADC sampling
speeds between 0.5 to 5 MSPS depending on
the settling performance required. OPAx323 is welloptimized
for power savings as it consumes just 1.6
mA typical quiescent current.
OPAx323 easily supports precision performance in
high gain voltage sensing applications such as
the wheatsone bridge, as it features maximum
offset drift of 2 μV/°C and thermal noise floor of
5.5 nV/rt-Hz with a minimum of 100 dB CMRR.
This unique combination of higher precision (low
offset, drift, noise, distortion, and CMRR) and higher
gain-bandwidth (fast settling and slewing) enables
use in multiple applications such as the motor
rotary encoders, microphone audio preamplfiers and
ultrasonic transducers.
OPAx323 achieves a high slew-rate of 33 V/μs
allowing for fast detection of faults in motor current
sensing applications. Unlike traditional amplifiers,
the zero-cross over input stage allows for identical
precision performance for both low and high-side
sensing applications, thus making OPAx323 the
best choice for current sensing in a variety of
end equipments such as the solar string inverters,
power delivery, grid and EV infrastructure. OPAx323S
devices provide shutdown functionality for additional
power savings and help disable the amplifier when
idle. The family features standard and small size as
well as leaded and QFN packages across all the
channel variants.