The OPA855 is fabricated on a low-voltage, high-speed, BiCMOS process. The internal, junction breakdown voltages are low for these small geometry devices, and as a result, all device pins are protected with internal ESD protection diodes to the power supplies as Figure 9-3 shows. There are two antiparallel diodes between the inputs of the amplifier that clamp the inputs during an overrange or fault condition.

Figure 9-3 Internal ESD Structure