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.