UNISONIC TECHNOLOGIES CO., LTD

PA3138

Preliminary

CMOS IC

www.unisonic.com.tw

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Copyright © 2016 Unisonic Technologies Co., Ltd

QW-R107-074 .a

DIRECT HEADPHONE DRIVER

WITH ADJUSTABLE GAIN



DESCRIPTION

The UTC PA3138 is a pop-free stereo headphone amplifier with

the integrated charge pump generating the negative supply rail

which allows the removal of the output DC-blocking capacitors. The

UTC PA3138 provides a clean, pop-free ground-biased audio

signal. The UTC PA3138 is capable of driving 25mW into a 32-Ω

load with 3.3-V supply voltage. The device has differential inputs

and uses external resistors for flexible gain setting. Gain can be

configured individually for each channel. The device can also be

configured as a second-order low-pass filter and is ideal for

interfacing with PWM audio sources.

The UTC PA3138 has built-in active-mute control for pop-free

audio on/off control. The UTC PA3138 has an external

under-voltage detector that mutes the output when monitored

voltage drop below set value.

Using the UTC PA3138 in audio products can reduce

component count considerably compared to traditional headphone

amplifiers.



FEATURES

* Low THD+N<0.01% at 10mW Into 32Ω

* Stereo Direct Headphone Amplifier driver

40 mW Into 32Ω With 3.3-V Supply

* Integrated charge pump Generates Negative Supply

Rail

* High SNR, >90dB

* Ground-Referenced Outputs Eliminate

DC-Blocking Capacitors

* Differential Input and Single-Ended Output

* Adjustable Gain by External Gain-Setting Resistors

* Pop-Free Under-Voltage Protection

* Configurable as a Second-Order Low-Pass Filter

Ideal for PWM Audio Sources

* Short-Circuit Protection

* Click- and Pop-Reduction Circuitry

* Active Mute Control for Pop-Free Audio On/Off

Control

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ORDERING INFORMATION

Ordering Number

Package

Packing

PA3138G-P14-R

TSSOP-14

Tape Reel