TPA6138A2 DirectPath™ Headphone Driver With Adjustable Gain
1 Features
- Stereo DirectPath™ Headphone Amplifier
- 40 mW Into 32 Ω With 3.3-V Supply
- Low THD+N < 0.01% at 10 mW Into 32 Ω
- High SNR, >90 dB
- Differential Input and Single-Ended Output
- Adjustable Gain by External Gain-Setting Resistors
- Configurable as a Second-Order Low-Pass Filter
- Ideal for PWM Audio Sources
- Low DC Offset, <1 mV
- Ground-Referenced Outputs Eliminate DC-Blocking Capacitors
- Reduce Board Area
- Reduce Component Cost
- Improve THD+N Performance
- No Degradation of Low-Frequency Response Due to Output Capacitors
- Short-Circuit Protection
- Click- and Pop-Reduction Circuitry
- External Undervoltage Mute
- Active Mute Control for Pop-Free Audio On/Off Control
- Space-Saving TSSOP Package
2 Applications
- LCD and PDP TV
- Blu-ray Disc™, DVD Players
- Set-Top Boxes
- Mini/Micro Combo Systems
- Sound Cards
- Laptops
3 Description
The TPA6138A2 is a pop-free stereo headphone amplifier designed to allow the removal of the output dc-blocking capacitors for reduced component count and cost. The device is ideal for single-supply electronics where size and cost are critical design parameters.
Designed using TI’s patented DirectPath™ technology, The TPA6138A2 is capable of driving 25 mW into a 32-Ω load with 3.3-V supply voltage. The device has differential inputs and uses external gain-setting resistors that supports a gain range of ±1 V/V to ±10 V/V. 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. Audio output compiles with ±8-kV IEC ESD protection, requiring just a simple resistor-capacitor ESD protection circuit. The TPA6138A2 has built-in active-mute control for pop-free audio on/off control. The TPA6138A2 has an external undervoltage detector that mutes the output when the power supply is removed, ensuring a pop-free shutdown.
Using the TPA6138A2 in audio products can reduce component count considerably compared to traditional headphone amplifiers. The TPA6138A2 does not require a split-rail power supply or a dc blocking capacitor. The TPA6138A2 integrates its own charge pump to generate a negative supply rail that provides a clean, pop-free ground-biased audio signal.
The TPA6138A2 is available in a 14-pin TSSOP.
Device Information(1)
| PART NUMBER | PACKAGE | BODY SIZE (NOM) |
|---|---|---|
| TPA6138A2 | TSSOP (14) | 5.00 mm × 4.40 mm |
- For all available packages, see the orderable addendum at the end of the datasheet.
Simplified Diagram
4 Revision History
Changes from A Revision (May 2011) to B Revision
- Added Pin Configuration and Functions section, ESD Ratings table, Feature Description section, Device Functional Modes, Application and Implementation section, Power Supply Recommendations section, Layout section, Device and Documentation Support section, Parameter Measurement Information section, and Mechanical, Packaging, and Orderable Information section Go
- Added the information in Section 8.1 as "Direct Path Headphone Driver" to Feature Description sectionGo
- Removed section "Gain-Setting Resistors" Go
Changes from * Revision (January 2011) to A Revision
