1 Features

• Ultra-low input bias current:

– 20 fA (tested max) at 25ºC and 85ºC

• Low noise:

– 0.05 fA/√Hz at 0.1 Hz

– 15 nV/√Hz at 1 kHz

• High dc precision:

– ±5 μV input offset voltage

– ±0.1 μV/°C offset voltage drift

• Wide bandwidth: 2.5-MHz GBW

• Low quiescent current: 275 μA

• EMI and RFI filtered inputs

• High precision guard buffer

• Wide supply: ±2.25 V to ±8 V, 4.5 V to 16 V

• Rail-to-rail input and output

• High capacitive load drive capability: 1 nF

• Operating temperature range: –40ºC to +125ºC

• Industry standard package:

– 8-pin SOIC

2 Applications

• Electrochemical meter - pH meter

• Lab and field Instrumentation

• Mass spectrometer

• Ion chromatography (IC) instrument

• Spectrophotometer

3 Description

The OPA928 is a new generation, 16‑V, femtoampere

input bias, e-trim™ operational amplifier. This device

offers an ultra-low input bias current of 20 fA (max) at

25ºC and 85ºC. The OPA928 input bias performance

is tested at production at both temperatures.

The device features near-zero input bias plus

outstanding dc precision and ac performance,

including rail-to-rail input/output, low offset voltage

(±5 μV, typical), low offset drift (±0.1 μV/°C, typical),

and low current noise (0.05 fA/√Hz at 0.1 Hz).

These features make the OPA928 an excellent choice

for low-light photodiode and high source-impedance

applications.

The OPA928 features an internal, high precision

guard buffer to protect high impedance input

traces from undesirable current leakage in sensitive

applications. The OPA928 packaging and pin out is

designed to support low-leakage circuit designs.

The OPA928 is specified from –40°C to +125°C.