TAS6421-Q1: TAS6421 minimum component count to connect A/D converter.

Victor,

I am sorry to say, you will need to have digital input as well as I2C control for the TAS6421-Q1  amp at high temps.

Have you looked at the TAS5421-Q1 mono amplifier.  What power level do you need and what is the load impedance?   I takes an analog signal in, and does not need I2C to function.

Hello Gregg,

In the final design we have High temperature microprocessor, so actually the TAS6421 offers massive power in a small pack, on a negative side, we have to carefully condition the supplies at high temperature this is tricky. I have ordered two evaluation boards and QTY=50 pcs as a starter.  But, development prototype we need to be a little more hands on in order we can determine what has failed.  So, actually as long term solution it may be OK, the jury is still out? 

Unfortunately the challenges do not stop with the high temperature range (5'C to 150'C).

The piezo electric transducer impedance (load) has a capacitance of 10uF, in the prototype MAX9744 Class-D Amplifier design we only need 15Wayys of power and for short duration this worked well, but we need something with a little more grunt for final design, yes we will never need more than 20W, but we cannot afford additional unwanted heating.  I use a small resistor and inductor to ensure Rmin is never achieved and also reduce HF gain.

You are Right the TAS5421-Q1 does look more suitable, I have some concerns the thermal resistance is actually quite high almost 40’C, and does the part have a thermal shutdown or can this be disabled. Does the Eval board come this its own I2C controller that will work when hot. Or do I again need to consider a remote I2C to use outside oven?  If is will work between 125 and 150'C it does have the advantage over that of the MAX9744.

Thanks for your help.

Victor

Hello Greg, 

OK, I have got the TAS6421EVAL=2/ and QTY= 50 pcs off TAS6421:

Project scope has changed:  i will have no micro ?

But i have been informed that I will not have a I²C interface. Or can the TAS6421 be controled by a state machine?

I need to get a TI part that is a direct replacement for analogue amplifier all be it, it has to be class-D as there is a 20uF capacitive piezo load. The good news is we have a very limited B/W of 0.5 to 5kHz. But I am ideally looking for a maximum power of about 20W. Ideally something similar to the MAX9700?  You are right i could go back to the MAXIM part but was hoping for a tiny bit more power, maybe 2watts/5watts more?

Please would you put me out of my misery, ideally before thanks giving ?