1 Features

• Zero cross amplifier for 1.7V to 5.5V applications

• High rail-to-rail CMRR: 114dB typical

• High gain-bandwidth product: 20MHz

• Fast slew-rate: 33V/μs typical

• Fast 0.01 settling: 200ns typical for 2V step

• Low input offset voltage: ±150μV typical

• Low noise floor: 5.5nV/√Hz typical at 10kHz

• High output current: ±110mA typical ISC at 5.5V

• Quiescent current: 1.6mA/ch typical

• Rail-to-rail input and output

• Unity-gain stable

• Drives up to 150pF 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 (1.7V to 5.5V), highbandwidth

(20MHz) 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 20MHz

provides a fast settling response for ADC sampling

speeds between 0.5MSPS to 5MSPS depending

on the settling performance required. The OPAx323

is well-optimized for power savings as the device

consumes just 1.6mA typical quiescent current.

The OPAx323 easily supports precision performance

in high gain voltage sensing applications such as the

wheatsone bridge, as it features maximum offset drift

of 2μV/°C and thermal noise floor of 5.5nV/rt-Hz with

a minimum of 100dB 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 preamplifiers

and ultrasonic transducers.

The OPAx323 achieves a high slew-rate of 33V/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.