TDA7296 Power Supply Pins Question

mrfeedback · 8th April 2011, 02:06 PM

As shown below, the TDA7296 audio amplifier has separate connections for the output stage and input stage power supplies.
Has anybody tried separate supplies and did anybody try regulated supplies for the input stage ?.

Eric.

ilimzn · 8th April 2011, 04:17 PM

Yes, use the search option.
It is IMPERATIVE that -Vs (pin 8) is always the most negative voltage on the chip, you should NEVER supply -PVs (pin 15) without Vs or the chip will literally explode.
The reason for this is pin 8 is tied to the substrate. The quick fix is to put a schottky diode between pin 8 (anode) and pin 15 (cathode) so that the maximum difference is about 0.4V. Pin 8 can be more negative than pin 15 (within limitations set in the datasheet) but the opposite must always be avoided.
To my ears this chip sounds really good with regulated front end supplies. Using higher front end positive supply (negative is not as relevant due to internal topology) compared to output stage supply also makes it possible to completely omit output bootstrapping. The topology used has higher PSRR from the negative rail so stabilizing the positive front end supply cleans up the output quite a lot. You cannot get the full theoretical power output, but then you cannot do this anyway without the specialapplication circuit from the datasheet, due to limited dissipation of the TDA chip.

8th April 2011, 02:06 PM	#1
mrfeedback diyAudio Member Join Date: Feb 2002 Location: Perth, Australia.	TDA7296 Power Supply Pins Question As shown below, the TDA7296 audio amplifier has separate connections for the output stage and input stage power supplies. Has anybody tried separate supplies and did anybody try regulated supplies for the input stage ?. Eric. __________________ I believe not to believe in any fixed belief system.

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8th April 2011, 04:17 PM	#2
ilimzn diyAudio Member Join Date: Feb 2005 Location: Zagreb	Yes, use the search option. It is IMPERATIVE that -Vs (pin 8) is always the most negative voltage on the chip, you should NEVER supply -PVs (pin 15) without Vs or the chip will literally explode. The reason for this is pin 8 is tied to the substrate. The quick fix is to put a schottky diode between pin 8 (anode) and pin 15 (cathode) so that the maximum difference is about 0.4V. Pin 8 can be more negative than pin 15 (within limitations set in the datasheet) but the opposite must always be avoided. To my ears this chip sounds really good with regulated front end supplies. Using higher front end positive supply (negative is not as relevant due to internal topology) compared to output stage supply also makes it possible to completely omit output bootstrapping. The topology used has higher PSRR from the negative rail so stabilizing the positive front end supply cleans up the output quite a lot. You cannot get the full theoretical power output, but then you cannot do this anyway without the specialapplication circuit from the datasheet, due to limited dissipation of the TDA chip.