8 Detailed Description

8.1 Overview

The OPA1637 is a low-noise, low-distortion fully-differential amplifier (FDA) that features Texas Instrument's

super-beta bipolar input devices. Super-beta input devices feature very low input bias current as compared to

standard bipolar technology. The low input bias current and current noise makes the OPA1637 an excellent

choice for audio applications that require low-noise differential signal processing without significant current

consumption. This device is also designed for analog-to-digital audio input circuits that require low noise in a

single fully-differential amplifier. This device achieves lower current consumption at lower noise levels than what

is achievable with two low-noise amplifiers. The OPA1637 also features high-voltage capability, which allows the

device to be used in ±15-V supply circuits without any additional voltage clamping or regulators. This feature

enables a direct, single amplifier for a 24-dBm differential output drive (commonly found on mixers and digital

audio interfaces) without any additional amplification.

8.2 Functional Block Diagram

VS+

IN±

+

±

Low Noise

Differential I/O

Amplifier

IN+

5 M

OUT+

OUT±

+

±

+

±

VCM

Error

Amplifier

VOCM

VS+

5 M

PD

VS±

VS±

1 µA

OPA1637

SBOSA00B – DECEMBER 2019 – REVISED AUGUST 2020

www.ti.com

16

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