Bridged load (BTL) audio power amplifier | Heisener Electronics
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Bridged load (BTL) audio power amplifier

Technology Cover
Post Date: 2023-03-17

The TPA751 is a bridging load (offline) audio power amplifier developed specifically for low-voltage applications requiring built-in speakers. The amplifier comes in a 3.0 x 3.0 mm Microstar Primary (BGA), 8-pin SOIC surface mount package and surface mount PowerPAD MSOP. Using a 3.3v power supply, the TPA751 can deliver 250 mw of continuous power to offline 8-Ω loads at less than 0.6% (THD + N) over the entire voice band frequency.

Although the device features at 20 KHZ, its operation is optimized for narrowband applications such as wireless communications. In most applications, the off-line configuration eliminates the need for external coupled capacitors at the output, which is especially important for small battery-powered devices. The device has a shutdown mode for power-sensitive applications with a power current of 1.5 nA when shut down.

Pin description


BTL Mode Test Circuit


TPA751 Application Circuit                  



● Fully Specified for 3.3-V and 5-V Operation

● Wide Power Supply Compatibility 2.5 V − 5.5 V

● Power Supply Rejection at 217 Hz

   − 84 dB at VDD = 5 V

   − 81 dB at VDD = 3.3V

● Output Power for RL = 8 Ω

   − 700 mW at VDD = 5 V

   − 250 mW at VDD = 3.3V

● Ultralow Supply Current in Shutdown Mode.. 1.5 nA

● Thermal and Short-Circuit Protection

● Surface-Mount Packaging

   −  SOIC

   −  PowerPAD  MSOP

   −  MicroStar Junior  (BGA)

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