EVM Basic Function/Block Diagram
and NPN transistor circuit is used to create the 3-V supply for the TPA2001D1 and TLV2464A; therefore, the user only needs to apply the single-supply voltage. A+ supply is used for powering the TAS5111 and is input for the zener diode/NPN transistor circuit used to generate the 3-V supply for the TPA2001D1 and TLV2464A.
To avoid potential damage to the EVM board, make sure that the correct cables are connected to their respective terminals as labeled on the EVM board.
Stresses above 29.5-V maximum voltage rating may cause permanent damage to the TAS5111.
1.2.2TPA2001D1 and TLV2464A Supply Voltage (3-V Reference)
The 3-V supply is generated by a 3.9-V zener diode, an NPN transistor, and a few resistors to supply VDD for the TPA2001D1 and TLV2464A. The 3-V supply voltage goes through a 20-Ωresistor to filter any noise. Test point 3V is placed after the 20-Ωresistor to allow the user to remove the 20-Ωresistor and insert an external 3-V supply. If an external supply is inserted, the voltage needs to be greater than 2.75 V to enable proper operation of the TPA2001D1 and less than 3.6 V to allow proper voltage levels to the inputs of the TAS5111.
When applying an external voltage reference through test point 3V, ensure that it does not exceed +3.6 V. Otherwise, this can permanently damage the installed device under test (DUT).
1.3 EVM Basic Function/Block Diagram
The APA100 EVM uses the TPA2001D1 as the analog modulator. The TAS5111 level shifts the 3-V, peak-to-peak output to the 18-V to 29.5-V, peak-to-peak output level of the TAS5111 enabling high−power output. The TLV2464A is used for the input gain stage, to provide a buffered midsupply voltage (1.5 V) and as feedback. The feedback improves total harmonic distortion (THD) and gives the amplifier power supply rejection, which allows the amplifier to have excellent audio performance even with a noisy power supply. Chapter 4, Technical Information provides more details about the component selection and feedback. A block diagram of the reference design is shown in Figure 1−2.
