I once applied got a project as a freelancer at upwork, and the project was to make a bluetooth audio telephone system and while doing this project I had bought couple of stereo Headphone Amplifier amplifier TPA6138A2PWR but later on I did not need them. Today while cleaning up things, I found the TPA6138A2PWR. I forgot what it was and had to make quick google search.
The TPA6138A2PWR is a stereo headphone amplifier from Texas Instruments, designed for high-quality audio applications where space and power efficiency are critical. It utilizes TI’s patented DirectPath™ technology, allowing for ground-referenced outputs without the need for bulky DC-blocking capacitors, thereby reducing component count and cost.
🔧 Key Features
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Output Power: Delivers up to 40 mW per channel into a 32 Ω load with a 3.3 V supply.
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Low Distortion: Total Harmonic Distortion plus Noise (THD+N) is less than 0.01% at 10 mW into 32 Ω.
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High Signal-to-Noise Ratio (SNR): Greater than 90 dB, ensuring clear audio output.
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Adjustable Gain: Gain can be set externally using resistors, supporting a range from ±1 V/V to ±10 V/V, configurable per channel.
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Differential Inputs: Accepts differential input signals and provides single-ended outputs.
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Low DC Offset: Less than 1 mV, minimizing unwanted noise.
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Integrated Features:
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Short-Circuit Protection
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Click-and-Pop Reduction Circuitry
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Active Mute Control for pop-free audio on/off transitions
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External Undervoltage Mute to prevent pops during power-down
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Package: Available in a compact 14-pin TSSOP package.
📦 Applications
The TPA6138A2PWR is ideal for:
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Portable audio devices
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Smartphones and tablets
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LCD TVs and Blu-ray/DVD players
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Sound cards and other audio peripherals
Its design is particularly beneficial in systems where eliminating output capacitors is advantageous, such as in space-constrained or battery-powered devices.
🎧 2. TPA6138A2PWR – Stereo Headphone Amplifier Applications
| Project Type | Application | How It’s Used |
|---|---|---|
| ESP32 (with DAC/I2S) | Audio output | Connect ESP32’s I2S or DAC output to TPA6138A2 to drive headphones/speakers |
| Arduino with I2S Audio Module | Sound feedback | Use for alerts/voice output in smart home or robot |
| Robotics | Voice assistant robot | Combine with voice synthesis (ESP32 + Google TTS or wav files) to speak instructions |
| Drone (FPV Audio) | Microphone to ground pilot | Amplify microphone audio and transmit with video stream |
🎧 Why TPA6138A2? – High-quality audio, low power, low noise — perfect for headphone-level audio in embedded systems.
