7 Detailed Description

7.1 Overview

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

in-package trim technology for high-precision performance with a 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 a 1/f noise corner at 25 Hz. The OPAx863A work with a wide-

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

with a 2.7

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

an excellent amplifier choice 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 that require a wide dynamic input range and good SNR.

The device includes an overload power limit feature that limits the increase in quiescent current with overdriven

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

Section 7.3.2.1. The amplifier 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, and a turn-on and turn-off time less than 8 µs.

7.2 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

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OPA863A, OPA2863A

SBOSA95D – MAY 2022 – REVISED DECEMBER 2023

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