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TPA3136D2, TPA3136AD2

SLOS938D – MAY 2016 – REVISED MARCH 2017

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9.3 Feature Description

9.3.1 Fixed Analog Gain

The analog gain of the TPA3136D2/TPA3136AD2 is fixed to 26 dB.

9.3.2

SD Operation

The TPA3136D2/TPA3136AD2 device employs a shutdown mode of operation designed to reduce supply current

held high (see specification table for trip point) during normal operation when the amplifier is in use. Pulling SD

low causes the outputs to mute and the amplifier to enter a low-current state. Never leave SD unconnected,

because amplifier operation would be unpredictable.

For the best power-off pop performance, place the amplifier in the shutdown mode prior to removing the power

supply voltage.

9.3.3 PLIMIT

The PLIMIT operation will, if selected, limit the output voltage level to a voltage level below the supply rail. In this

case the amplifier operates as if it was powered by a lower supply voltage, and thereby limiting the output power

by voltage clipping. PLIMIT threshold is set by the PLIMIT pin voltage.

Figure 16. PLIMIT Circuit Operation

The PLIMIT circuit sets a limit on the output peak-to-peak voltage. The limiting is done by limiting the duty cycle

to a fixed maximum value. The limit can be thought of as a "virtual" voltage rail which is lower than the supply

connected to PVCC. The "virtual" rail is approximately four times the voltage at the PLIMIT pin. The output

voltage can be used to calculate the maximum output power for a given maximum input voltage and speaker

impedance.