OPA180, OPA2180, OPA4180

SBOS584D – NOVEMBER 2011 – REVISED MAY 2014

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Feature Description (continued)

When the operational amplifier connects into a circuit, the ESD protection components are intended to remain

inactive and not become involved in the application circuit operation. However, circumstances may arise where

an applied voltage exceeds the operating voltage range of a given pin. Should this condition occur, there is a risk

that some of the internal ESD protection circuits may be biased on, and conduct current. Any such current flow

occurs through ESD cells and rarely involves the absorption device.

If there is an uncertainty about the ability of the supply to absorb this current, external zener diodes may be

added to the supply pins. The zener voltage must be selected such that the diode does not turn on during normal

operation.

However, its zener voltage should be low enough so that the zener diode conducts if the supply pin begins to

rise above the safe operating supply voltage level.

8.4 Device Functional Modes

The OPA180, OPA2180, and OPA4180 are powered on when the supply is connected. These devices can be

operated as a single-supply operational amplifier or dual-supply amplifier depending on the application. In single-

supply operation with V– at ground (0 V), V+ can be any value between 4 V and 36 V. In dual-supply operation

the supply voltage difference between V– and V+ is from 4 V to 36 V. Typical examples of dual-supply

configuration are ±5 V, ±10 V, ±15 V, and ±18 V. However the supplies must not be symmetrical. Less common

examples are V– at –3V and V+ at 9 V or V– at –16 V and V+ at 5 V. Any combination where the difference

between V– and V+ is at least 4 V and no greater than 36 V is within the normal operating capabilities of these

devices.

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