Texas Instruments Audio Power Amplifier Evaluation Module TPA1517DWPEVM TPA1517DWPEVM Datenbogen

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Controls

Mute/Standby Select - S1: Jumper in place sets low current standby
mode.  Jumper out sets mute mode.  Mode is activated by Switch S3
or external TTL input at Mute input.

Depop Select - S2: Jumper in place selects enhanced Depop mode.
Jumper out disables depop circuitry.

Mute Input/Switch - S3: Low activates mute/standby (S1) circuitry.
Switch S3 is a momentary action push button.  Press S1 to mute.

R1/R2 Gain Control Pots:  3/4 turn adjusts amplifier Volume.
Clockwise increases volume.

The M/SB pin of the IC (PIN 17) operates over a range of voltages. 0
to 2 volts is standby mode, 3.4 to 8.8 volts is mute mode and 9.2 to
Vcc is operate mode.  Transistors Q1 and Q2 form a network to allow
TTL control of the M/SB function.  S1 determines the active voltage
range of the transistor circuit into M/SB.  When S1 is in place
transistor Q2 pulls M/SB to 0 volts (Standby mode), when S1 is out,
resistor R8 forms a divider network with R3 to set the voltage in the
Mute range.  Typically mute mode pop noises are not as loud as
standby mode pops.

Diodes D1 and D2 when enabled by S2 allow the charge on the output
coupling caps to drain during standby mode.  This helps reduce pop
noises when returning to operating mode.