Datasheet

C
O
Conventional
V
OUT
GND
V
OUT
GND
V
BIAS
Capless
DirectPath™
GND
V
DD
V
SS
V
OUT
C
O
V
OUT
V
OUT
ELIMINATING TURN-ON POP AND POWER SUPPLY SEQUENCING
TPA6135A2
SLOS623A – FEBRUARY 2009 – REVISED APRIL 2009 .................................................................................................................................................. www.ti.com
Figure 27. Amplifier Applications
The DirectPath™ amplifier architecture operates from a single supply voltage and uses an internal charge pump
to generate a negative supply rail for the headphone amplifier. The output voltages are centered around 0 V and
are capable of positive and negative voltage swings as shown in the bottom drawing of Figure 27 . DirectPath
amplifiers require no output dc-blocking capacitors. The headphone connector shield pin connects to ground and
will interface with headphones and non-headphone accessories. The TPA6135A2 is a DirectPath amplifier.
The TPA6135A2 has excellent noise and turn-on / turn-off pop performance. It uses an integrated click-and-pop
suppression circuit to allow fast start-up and shutdown without generating any voltage transients at the output
pins. Typical start-up time from shutdown is 5 ms.
DirectPath technology keeps the output dc voltage at 0 V even when the amplifier is powered up. The DirectPath
technology together with the active pop-and-click suppression circuit eliminates audible transients during start up
and shutdown.
Use input coupling capacitors to ensure inaudible turn-on pop. Activate the TPA6135A2 after all audio sources
have been activated and their output voltages have settled. On power-down, deactivate the TPA6135A2 before
deactivating the audio input source. The EN pin controls device shutdown: Set to 0.6 V or lower to deactivate the
TPA6135A2; set to 1.3 V or higher to activate.
14 Copyright © 2009, Texas Instruments Incorporated
Product Folder Link(s) :TPA6135A2