8 Detailed Description

8.1 Overview

The THP210 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 THP210 an excellent choice

for high-performance applications that require low-noise, differential-signal processing without significant current

consumption. This device is also designed for analog-to-digital input circuits that require low offset and low noise

in a single fully-differential amplifier. The THP210 features high-voltage capability, which allows the device to

be used in ±15-V supply circuits without any additional voltage clamping or regulators. Because this device is

unity-gain stable, the device allows high-voltage input signals to be attenuated to the low-voltage ADC domain

without requiring additional compensation techniques.

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

8.3 Feature Description

8.3.1 Super-Beta Input Bipolar Transistors

The THP210 is designed on a modern bipolar process that features TI's super-beta input transistors. Traditional

bipolar transistors feature excellent voltage noise and offset drift, but suffer a tradeoff in high input bias current

(IB) and high input bias current noise. Super-beta transistors offer the benefits of low voltage noise and low

offset drift with an order of magnitude reduction in input bias current and reduction in input bias current noise.

For many filter circuits, input bias current noise can dominate in circuits where higher resistance input resistors

are used. The THP210 enables a fully-differential, low-noise amplifier design without restrictions of low input

resistance at a power level unmatched by traditional single-ended amplifiers.

8.3.2 Power Down

The THP210 features a power-down circuit to disable the amplifier when a low-power mode is required by the

system. In the power-down state, the amplifier outputs are in a high-impedance state, and the amplifier total

quiescent current is reduced to less than 20 µA.

THP210

SBOS932C – JANUARY 2020 – REVISED MARCH 2021

www.ti.com

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