SERVICE MANUAL
21
2. TFA9842AJ
2-channel audio amplifier with volume control (SE: 1 W to 7.5 W)
2.1 General
description
The TFA9842AJ contains two identical audio power amplifiers. The TFA9842AJ can be used as two
Single-Ended (SE) channels with a volume control. The maximum gain is 26 dB.
The TFA9842AJ comes in a 9-pin DIL-bent-SIL (DBS9P) power package. The TFA9842AJ is pin compatible
with the TFA9843AJ, TFA9843(B)J, TFA9842(B)J and TFA9841J. The difference between the TFA9843AJ and
the TFA9843(B)J,TFA9842(B)J, TFA9841J is the functionality of pin 7. The TFA9843AJ has a Volume Control
(VC) on pin 7. The TFA9843(B)J, TFA9842(B)J and TFA9841 J have a mode select (Mode) on pin 7. The
TFA9842AJ contains a unique protection circuit that is solely based on multiple temperature measurements
inside the chip. This gives maximum output power for all supply voltages and load conditions with no
unnecessary audio holes. Almost any supply voltage and load impedance combination can be made as long
as thermal boundary conditions (number of channels used, external heatsink and ambient temperature) allow
it.
2.2 Features
2 Channel SE: 1 W to 7.5 W operation possibility
Soft clipping
Input clamps
Volume control
Standby and mute mode
No on/off switching plops
Low standby current
High supply voltage ripple rejection
Outputs short-circuit protected to ground, supply and across the load
Thermally protected
Pin compatible with the TFA9843AJ, TFA9843(B)J, TFA9842(B)J, TFA9841J.