TDA 1543 - How hot?

[pixpop]

I've just finished my version of the DDDAC, with 8 x TDA1543 in parallel. I'm running them at 8 Volts, and they run warm, but definitely not hot.

Given the various designs I've seen, I expected they would get very hot - i.e. too hot - unless heatsinked. They don't seem like they need heatsinks at all to me.

The 8 of them draw about 350 mA total at 8 Volts.

How hot should I expect them to get?


Re reference voltage: Is the idea to set this to half the supply voltage?

Neil

[dddac]

Originally posted by pixpop
I've just finished my version of the DDDAC, with 8 x TDA1543 in parallel. I'm running them at 8 Volts, and they run warm, but definitely not hot.

Given the various designs I've seen, I expected they would get very hot - i.e. too hot - unless heatsinked. They don't seem like they need heatsinks at all to me.

The 8 of them draw about 350 mA total at 8 Volts.

How hot should I expect them to get?


Re reference voltage: Is the idea to set this to half the supply voltage?

Neil

aprox 60-70 degrees.....

regards
doede

[pixpop]

--> aprox 60-70 degrees.....

Do you mean Celsius, or Farenheit?

I would say they are about 40 Celsius. I think about 50 Celsius is when things become too hot to touch, and these are way cooler than that.

BTW, they work fine, and the DAC sounds great, I'm just puzzled about the lack of heat.

Neil

[pburke]

what voltage are you feeding them? Doede's design is asking for 8.5V and that will make it 70 degrees Celsius easily

Peter

[pburke]

on second reading of your post - 8V is close - should be hotter. And 350ma for 8 of them is too low. I see about 2 amps with 16 of them. are you sure all 8 are connected to the circuit, especially the power pins?

Peter

[carlosfm]

Originally posted by pburke
what voltage are you feeding them? Doede's design is asking for 8.5V and that will make it 70 degrees Celsius easily

Peter

Some years ago, when I made my first TDA1543 dac, with single chip (sounds better than paralleled, but that's another story) and 8V PSU voltage, the dac got a little hot to touch.
As I had a handfull of them, and the chip was on a socket, I started changing dacs.
To my surprize, and always with 8V PSU, nothing changed, some TDA1543 chips got hot, others just warm, and others really cool.
I kept the chip that runned cooler, and I mean really cool, ambient temperature.

[pixpop]

--> are you sure all 8 are connected to the circuit, especially the power pins? <--

I just double checked, all of them read 8.05 Volts on my Fluke DMM. One difference I have is that the chips are connected to a ground plane, rather than stacked in a tower. Perhaps that is sucking away some heat, or perhaps I just have 'cool' chips.

[X.G.]

I had tried the 4 pcs of TDA1543 (construction like a tower) in 8V. a few minutes after power on,I heard the sound of dirtortion.I changed them in 7V,and solve the problem.

[pixpop]

OK, I just realized part of the problem. I've been doing my temperature testing with zero data. I think this turns off all the DAC switches, and gives the highest output voltage.

When I get home tonite, I'll set the data to all ones, so all the DAC switches should be on. I think this should give me the maximum dissipation, and the lowest output voltage.

[dddac]

Originally posted by pixpop
OK, I just realized part of the problem. I've been doing my temperature testing with zero data. I think this turns off all the DAC switches, and gives the highest output voltage.

When I get home tonite, I'll set the data to all ones, so all the DAC switches should be on. I think this should give me the maximum dissipation, and the lowest output voltage.

this is not the "solution" to the problem. The chips draw aprox 50mA each, regardless of sound is played or not.... so each chip dissipates 8 x 50m = 400mWatt. 8 pieces --> 3.2 Watt.

If they are stacked in a tower, they get hotter, than when each chip can radiate its own heat in free (cold) air, as you assembled the chips next to each other didn't you mention ?

doede