OPAx328 Precision, 40MHz, 1pA, Low-Noise, RRIO, CMOS Operational Amplifiers

With Shutdown

1 Features

• Precision with zero-crossover distortion:

– Low offset voltage: 50µV (maximum)

– High CMRR: 120dB

– Rail-to-rail I/O

• Wide bandwidth: 40MHz

• Low input bias current: 1pA (maximum)

• Low noise: 6.1nV/√Hz at 10kHz

• Slew rate: 30V/µs

• Fast 0.01% settling time: 180ns

• Single-supply voltage range: 2.2V to 5.5V

• Unity-gain stable

2 Applications

• Optical module

• Position sensor

• Multiparameter patient monitor

• CT and PET scanner

• Chemistry and gas analyzer

• Bidirectional 400-V and 800-V to LV

• Merchant network and server PSU

• String inverter

• Solar power optimizer

Σ

e-trim™

POR

V+

V

IN

+IN

OPAx328

Charge

pump

PMOS

input

pair

OUT

Block Diagram

3 Description

The single-channel OPA328, dual-channel OPA2328

and quad-channel OPA4328 (OPAx328) are a new

generation family of precision, low-voltage CMOS

operational amplifiers optimized for very low noise

and wide bandwidth.

The OPAx328 have a linear input stage with zero-

crossover distortion that delivers excellent common-

mode rejection ratio (CMRR) of 120dB (typical) over

the full input range. The input common-mode voltage

range extends 100mV beyond the negative and

positive supply rails. The output voltage typically

swings within 10mV of the rails.

The OPAx328 also use Texas Instrument's proprietary

e

‑trim™ operational amplifier technology, enabling a

unique combination of ultra-low offset and low input

offset drift without the need for any input switching or

auto-zero techniques.

Low-noise (6.1nV/√Hz) and high-speed operation

(40MHz, 30V/μs) make these devices a great choice

for driving sampling analog-to-digital converters

(ADCs).

The OPAx328 are also a great choice for high-

impedance-input, single-supply applications. Low

input bias current and low input capacitance allows

for high-frequency transimpedance gains at low

photocurrent operation (< 1nA).

Device Information

PART NUMBER

CHANNELS /

SHUTDOWN

PACKAGE(1)

OPA328

Single / No

DBV (SOT-23, 5)

OPA328S(2)

Single / Yes

DBV (SOT-23, 6)

OPA2328

Dual / No

D (SOIC, 8)

DGK (VSSOP, 8)

DRG (WSON, 8)

Dual / Yes

YBJ (DSBGA, 24)

OPA4328

Quad / No

PW (TSSOP, 14)

(1)

For more information, see Section 10.

(2)

Preview information (not Production Data).

OPA328, OPA2328, OPA4328

SBOS957F – FEBRUARY 2022 – REVISED OCTOBER 2025

An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,

intellectual property matters and other important disclaimers. UNLESS OTHERWISE NOTED, this document contains PRODUCTION

DATA.