8 Detailed Description

8.1 Overview

The OPAx863A bipolar voltage-feedback amplifiers offer 50 MHz gain-bandwidth product with a proprietary

in-package trim technology for high-precision performance with maximum 95 µV input offset voltage and 1.2

µV/

℃ offset drift. The OPAx863A are low-power, rail-to-rail input and output (RRIO) operational amplifiers with

a voltage noise density of 6.3 nV/√Hz and 1/f noise corner at 25 Hz. The OPAx863A work with a wide-supply

voltage range from 2.7 V to 12.6 V and consume only 800 µA quiescent current. The OPAx863A operate with

2.7 V supply, are RRIO capable, consume low-power, and offer a power-down mode, which makes them an

excellent choice of amplifiers for 3.3-V or lower voltage applications that need excellent ac performance. The

main and auxiliary input stages of the amplifier are matched for gain bandwidth product (GBW), noise and offset

voltage and designed for applications which require wide dynamic input range and good SNR.

The device includes an overload power limit feature which limits the increase in quiescent current with over-

driven and saturated outputs to either of the supply rails. For more details of this overload power limit feature,

see Section 8.3.2.1. The amplifier's output is protected against short-circuit fault conditions.

The OPAx863A feature a power-down mode (PD) with a PD quiescent current of 20 µA (maximum) with a 3

‑V

supply, with turn-on and turn-off time within less than 8 µs.

8.2 Functional Block Diagram

Auxiliary

NPN-

Stage

VS+

EN

Main

PNP-

Stage

VS–

EN

VS+ –1.6 V

VIN+

VIN–

VOUT

+

+

+

OPAx863A

CC

–

–

–

–

Output

Short-Circuit

Protection

Overload

Power

Limiting

PD

OPA863A, OPA2863A

SBOSA95C – MAY 2022 – REVISED AUGUST 2023

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