Operation
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1.2 TPA2025D1 Specifications
V
BAT
Supply voltage range 2.5 V to 5.2 V
I
DD
Supply current 3 A Maximum
P
O
Continuous output power per channel, 4 Ω, V
BAT
= 3.6 V 2 W
V
I
Audio input voltage 0 V to V
BAT
R
L
Minimum load impedance 4 Ω
2 Operation
This section describes how to operate the TPA2025D1EVM.
2.1 Quick-Start List for Stand-Alone Operation
Use the following steps when operating the TPA2025D1EVM as a stand-alone or when connecting the
EVM into existing circuits or equipment.
2.1.1 Power and Ground
1. Ensure the external power sources are set to OFF.
2. Set the power supply voltage between 2.3 V and 5.2 V. When connecting the power supply to the
EVM, attach the power supply ground connection to the GND connector first, and then connect the
positive supply to the VDD connector. Verify that correct connections are made to the banana jacks.
2.1.2 Audio
1. Ensure that the audio source is set to the minimum level.
2. Connect the audio source to the input RCA jack IN. In case of differential audio input, ensure that the
jumper, JP SE, is not inserted. In case of a single-ended audio input, ensure that the jumper, JP SE, is
inserted, thereby grounding IN+ through the input capacitor C2.
3. Connect a speaker (4 Ω to 32 Ω) to the output banana jacks, OUT+ and OUT–.
4. FLT Out+ and FLT OUT- test points allow the user to connect the outputs of the amplfier through an
RC filter for audio measurements. (Many audio analyzers will not give the correct readings on a
Class-D amplifier without additional filtering.) Note that the user must provide the necessary resistors,
R7 and R8 to complete the filters. The typical value for R7 and R8 is 1.0 kΩ.
5. The filtered output of the TPA2025D1 can be measured between test points FILT OUT– and FILT
OUT+
2.1.3 AGC Control
The TPA2025D1 has three selectable inflection point settings: 3.25 V, 3.55 V, and 3.75 V.
1. Remove the jumper, AGC, to select the 3.25-V inflection point (AGC1).
2. Install the jumper, AGC, between pins 2 and 3 to select the 3.55-V inflection point (AGC2).
3. Install the jumper, AGC, between pins 1 and 2 to select the 3.75-V inflection point (AGC3).
2.1.4 Amplifier Gain
The TPA2025D1 has a fixed setting of 20 dB.
2.1.5 Shutdown Controls
1. The TPA2025D1 provides shutdown control for the Class-D amplifier and the boost converter. The EN
pin enables the boost converter and Class-D amplifier. It is active high.
2. Press and hold pushbutton S1 to place the boost converter and the Class-D amplifier in shutdown.
Release pushbutton S1 to activate the Class-D amplifier and boost converter. The boost converter only
turns on if an audio signal (> 2 V
PEAK
) is present at one of the outputs (OUT+ or OUT-).
2
TPA2025D1 Audio Power Amplifier Evaluation Module SLOU310– September 2011
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