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.