Description
The TPA2000D4 is a 2-W stereo bridge-tied-load (BTL) class-D amplifier designed to drive speakers with as low as 4-O impedance. The amplifier uses TI’s second-generation modulation technique, which results in improved efficiency and SNR, and also allows the device to be connected directly to the speaker without the use of the LC output filter commonly associated with class-D amplifiers (this will result in an EMI which must be shielded at the system level). These features make the device ideal for use in notebook PCs where high-efficiency is needed to extend battery run-time. For speakers powered off the USB bus, the high-efficiency allows for higher output power levels without tripping the USB’s over-current circuitry. The gain of the amplifier is controlled by two input terminals, GAIN1, and GAIN0. This allows the amplifier to be configured for a gain of 5, 11, 17 and 23 dB. The differential input terminals are high-impedance CMOS inputs, and can be used as summing nodes. The headphone amplifier is a stereo single-ended (SE) class-AB amplifier which requires two external resistors per channel to set the gain. The MODE pin selects which amplifier is active; the unused amplifier is placed in shutdown to reduce supply current. Both the class-D BTL amplifier, and the class-AB SE amplifier include depop circuitry to reduce the amount of turnon pop at power up, when cycling SHUTDOWN, and when switching modes of operation. The TPA2000D4 is available in the 32-pin thermally-enhanced TSSOP package (DAP) which allows stereo 2-W continuous output power levels in 4-O loads when placed on a board with proper thermal board design. The TPA2000D4 operates over an ambient temperature range of –40°C to 85°C. These packages deliver levels of thermal performance that were previously only achievable in TO-220-type packages. Thermal impedances of less than 35°C/W are readily realized in multilayer PCB applications when using the DAP package.
- Filterless Operation
- Improved Efficiency
