3W filter-free Class D audio amplifier technology based on TPA2028D1 design

TI's TPA2028D1 is a mono 3W filter-free Class-D audio power amplifier with integrated volume control, dynamic range compression (DRC) and automatic gain control (AGC). The DRV/AGC function can be programmed through a digital I2C interface. It can provide 3W power (THD+N is 10%) to a 4-ohm load at 5V power supply, with an operating voltage range of 2.5V to 5.5V, an operating current of 1.8mA, and a shutdown current of 0.2uA. It is mainly used in wireless or cellular phones and PDAs, PNDs, DVD players, notebook computers, portable radios, game consoles, and educational toys. This article introduces the main features of the TPA2028D1, a functional block diagram, an

index test block diagram, and the performance, circuit diagram, and bill of materials (BOM) of the TPA2028D1YZFEVM evaluation board. 1,63 mm x 1,63 mm wafer chip-scale package (WCSP).

The DRC/AGC function in the TPA2028D1 is programmable via a digital I ² C interface. The DRC/AGC function can be configured to automatically prevent distortion of the audio signal and enhance quiet passages that are normally not heard. can be selected from –28 dB to +30 dB in 1-dB steps.

TPA2028D1 Key Features:

Fast AGC Start-up Time: 5 ms

Pin-out Compatible with TPA2018D1

Filter-Free Class-D Architecture

3 W Into 4 at 5 V (10% THD+N)

880 mW Into 8 at 3.6 V (10% THD+N)

Power Supply Range: 2.5 V to 5.5 V

Flexible Operation With/Without I ² C

Programmable DRC/AGC Parameters

Digital I ² C Volume Control

Selectable Gain from –28 dB to 30 dB in 1-dB Steps (when compression is used)

Selectable Attack, Release and Hold Times

4 Selectable Compression Ratios

Low Supply Current: 1.8 mA

Low Shutdown Current: 0.2 µA

High PSRR: 80 dB

AGC Enable/Disable Function

Limiter Enable/Disable Function

Short-Circuit and Thermal Protection

Space-Saving Package

1,63 mm × 1,63 mm Nano-Free WCSP (YZF)

TPA2028D1 Applications:

• Wireless or Cellular Handsets and PDAs

• Portable Navigation Devices

• Portable DVD Player

• Notebook PCs

• Portable Radio

• Portable Games •

Educational Toys

• USB Speakers

Figure 1. TPA2028D1 functional

block diagram Figure 2. TPA2028D1 indicator test block diagram

Figure 3. TPA2028D1 simplified application block diagram

TPA2028D1YZFEVM evaluation board

The TPA2028D1 evaluation module (EVM) is a complete, stand-alone audio board. It contains the TPA2028D1 WCSP (YZF) Class-D audio power amplifier.

TPA2028D1YZFEVM evaluation board indicators:



Figure 4. TPA2028D1YZFEVM evaluation board appearance

Figure 5. TPA2028D1YZFEVM evaluation board circuit diagram (1)

Figure 6. TPA2028D1YZFEVM evaluation board circuit diagram (2)

TPA2028D1YZFEVM evaluation board bill of materials (BOM):