TPA6138A2PW Headphone Driver

TPA6138A2PW is a headphone Driver introduced by Texas Instruments. It is a small, cost-effective IC with an Adjustable Gain through external resistors. The driver can deliver 25mW into 32 ohms load with just 3.3-V supply voltage. The chip has no DC blocking capacitors or split-rail power supply. Instead, it has a charge pump to generate a negative supply rail for the amplifiers for a clean ground-referenced output. Its outputs are compiled with ±8-kV IEC ESD protection and an ESD protection circuit.

TPA6138A2PW Headphone Driver

TPA6138A2PW Introduction

The stereo headphone amplifier is integrated with an Active mute control and an in-built pop-reduction circuitry to eradicate the noises during turn on/off. The Undervoltage protection facility in the integrated circuit helps to avoid damage and noise when the power supply is very low or removed and aids a pop-free shutdown. All these properties result in increased RF noise immunity.

TPA6138A2PW can be a better substitute for traditional headphone amplifiers due to its high performance and reduced component count. It can find its applications in consumer products. This tutorial shows the pin configuration, features, specifications, and applications. 

TPA6138A2PW Pinout

The following diagram shows the pinout of the TPA6138A2PW Headphone Driver:

TPA6138A2PW Headphone Driver pinout diagram

Pin Configuration

Let us discuss the pinout of the TPA6138A2PW Headphone Driver. The pin configuration detail in tabular is mentioned below:

Pin NumberPin NameFunction
1+INRPositive Right-channel OP-AMP input pin
2–INRNegative Right-channel OPAMP input pin
3OUTROutput Right-channel OP AMP pin
4GNDGround pin
5MuteActive-low, mute pin
6VSSNegative Power Supply pin
7CNCharge-pump flying capacitor negative connection pin
8CPCharge-pump flying capacitor positive connection pin
9VDDPositive Power Supply pin
10GNDGround pin
11UVPUnder Voltage Protection pin
12OUTLOutput Left-channel OP AMP pin
13–INL Negative Left-channel OP AMP input pin
14+INLPositive Left-channel OP AMP input pin

TPA6138A2PW Features and Specifications

Maximum Output Power40 mWatts
Operational Temperature-400C – 850C
Nominal Supply Current25 mA
Load Impedance32 ohms
Headphone Output Channels2-Channel Stereo
Output TypeAdjustable
Power Supply Rejection Ratio(PSSR)80 dB
Package TypeTSSOP, Surface mount
Pin Count14
  • Operating Voltage: 3 – 3.6 Volts
  • Signal-to-Noise Ratio: >90 dB
  • Dynamic Range: 100 dB
  • DC Offset: <1mV
  • Load Impedance: 32 ohms
  • Low THD+N < 0.01% at 10 mW Into 32 ohms

Detailed Features

Some of the detailed features of the TPA6138A2PW are listed below:

  • Adjustable Gain by External Gain setting Resistors.
  • It is ideal for PWM Audio Sources due to its arrangement as a Second-order Low-Pass filter to remove out-of-band noise.
  • It comes with an active Mute audio control for Pop-Free audio on/off control
  • TPA6138A2PW has differential input to minimize noise pickups but a single-ended output
  • The Outputs of the headphone driver are Ground-referenced to avoid degradation of Low-Frequency response and to improve THD+N performance.
  • It comes with Click-and-Pop reduction circuitry to eliminate the unwanted noise during turn on/off.
  • The driver has an integrated External UnderVoltage Mute and Short-Circuit Protection.
  • It also has an integrated charge pump to produce negative voltage for the operational amplifiers.
  • It is available in TSSOP Package.

TPA6138A2PW Internal Diagram

The internal Circuitry of the TPA6138A2PW Headphone Driver is provided for better understanding. It is as follows:

TPA6138A2PW internal circuit diagram

How to interface TPA6138A2PW?

To interface TPA6138A2PW Headphone Driver, one must follow the given schematic. The schematic diagram shows the connectivity of input and outputs in an audio system for gain adjustments and amplification.

TPA6138A2PW interfacing diagram with microcontroller

TPA6138A2PW Alternative Options

  • TS482
  • TPA6139A2
  • TPA6133A2
  • MAX13330


  • Laptops
  • Set-top boxes
  • Sound Cards
  • LCDs
  • DVD Players

2D Diagram

The following figure depicts the 2d model of the TPA6318A2PW Headphone Driver. It comes in the TSSOP-14 Package. It shows us the physical dimensions in millimeters required when a PCB card is designed.

2D diagram


The datasheet link is given below to see further details and specifications of the TPA6138A2PW Headphone Driver.

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