6.3 Feature Description

6.3.1 Low Operating Voltage

The OPAx397 family can be used with single or dual supplies from an operating range of VS = 1.7V (±0.85V) up

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

down to VS = 1.7V.

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

6.3.2 Low Input Bias Current

The typical input bias current of the OPAx397 is extremely low (typically 10fA). Input bias current is dominated by

leakage current from the ESD protection diodes, which is proportional to the area of the diode. The OPAx397 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 6-1 shows the equivalent circuit.

+

±

CORE

10

10

+IN

±IN

V+

V±

Figure 6-1. Equivalent Input Circuit

6.4 Device Functional Modes

The OPAx397 family is operational when the power-supply voltage is greater than 1.7V (±0.85V). The maximum

specified power-supply voltage for the OPAx397 is 5.5V (±2.75V).

www.ti.com

OPA397, OPA2397, OPA4397

SBOSA02A – AUGUST 2021 – REVISED APRIL 2025

Copyright © 2025 Texas Instruments Incorporated

Submit Document Feedback

17

Product Folder Links: OPA397 OPA2397 OPA4397