TDA8947J

The TDA8947J has the following features including SE: 1 W to 25 W, BTL: 4 W to 50 W operation possibility (2.1 system);Soft clipping;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 TDA8944AJ and TDA8946AJ.

The TDA8947J contains four identical audio power amplifiers. The TDA8947J can be used as: four Single-Ended (SE) channels with a fixed gain of 26 dB, two times Bridge-Tied Load (BTL) channels with a fixed gain of 32 dB or two times SE channels(26 dB gain) plus one BTL channel (32 dB gain) operating as a 2.1 system.The TDA8947J comes in a 17-pin Dil-Bent-Sil (DBS) power package. The TDA8947J is pin compatible with the TDA8944AJ and TDA8946AJ.The TDA8947J 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.

The TDA8947J contains two types of detection sensors: one measures local temperatures of the power stages and one measures the global chip temperature. At a local temperature of approximately 185 °C or a global temperature of approximately 150 °C, this detection circuit switches off the power stages for 2 ms. High impedance of the outputs is the result. After this time period the power stages switch on automatically and the detection will take place again; still a too high temperature switches off the power stages immediately. This protects the TDA8947J against shorts to ground, to the supply voltage and across the load, and against too high chip temperatures.The protection will only be activated when necessary, so even during a short-circuit condition, a certain amount of (pulsed) current will still be flowing through the short, just as much as the power stage can handle without exceeding the critical temperature level.