4.2.1 Initial Temperature

For this test, the thermal foldback has been disabled and an initial temperature of 23°C is observed in Figure 3 using the temperature monitor.

A hot air stream is used to heat up the device. As the hot air is applied to the device, the temperature rises until it triggers the over-temperature protection causing the device to shut down.

Figure 3. Temperature Monitor - Ambient Temperature

At this initial temperature, a full-scale input signal is played. Figure 4 shows the output of the amplifier at full-scale; this plot shows the differential signal across the speaker load, the amplitude of this signal is later compared versus the output signal when thermal foldback is triggered.

Figure 4. Output Waveforms - Ambient Temperature