8.3 Feature Description

8.3.1 Low Operating Voltage

The OPAx392 family can be used with single or dual supplies from an operating range of VS = 1.7 V (±0.85 V) up

to 5.5 V (±2.75 V). The offset voltage is trimmed at 5.0 V, however, the device maintains ultra-low offset voltages

down to VS = 1.7 V.

Key parameters that vary over the supply voltage or temperature range are shown in the Typical Characteristics.

8.3.2 Low Input Bias Current

The typical input bias current of the OPAx392 is extremely low (typically 10 fA). Input bias current is dominated

by leakage current from the ESD protection diodes, which is proportional to the area of the diode. The

OPAx392 is able to achieve ultra-low input bias current as a result of modern process technology and advanced

electrostatic discharge (ESD) protection design that minimizes the area of the diode.

In overdriven conditions, the bias current can increase significantly. The most common cause of an overdriven

condition occurs when the operational amplifier is outside of the linear range of operation. When the output of

the operational amplifier is driven to one of the supply rails, the feedback loop requirements cannot be satisfied

and a differential input voltage develops across the input pins. This differential input voltage results in the

forward-biasing of the ESD cells. Figure 8-1 shows the equivalent circuit.

+

±

CORE

10

10

+IN

±IN

V+

V±

Figure 8-1. Equivalent Input Circuit

8.4 Device Functional Modes

The OPAx392 family is operational when the power-supply voltage is greater than 1.7 V (±0.85 V). For devices

that use the EN function (see Section 6), the devices are disabled when the EN pin is low. In this state, quiescent

current is significantly reduced, and the output is high impedance. The maximum specified power-supply voltage

for the OPAx392 is 5.5 V (±2.75 V).

OPA392, OPA2392

SBOS926D – JANUARY 2021 – REVISED DECEMBER 2022

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