TI Samples for Digital audio

You can also get everything but the TAS5015 in single unit quantities from Digikey. They're pretty cheap too. They also have the TAS5100 output driver IC, but only in quantities of 46.

I've given some thought to doing something with these chips, but it'll be complex. Unless you use TI's TAS5100 output bridge (very difficult for DIY because of the way the heatsink is mounted), you'll have to design a discrete H-bridge for the output, and probably some sort of switching power supply so that you can move the rail voltage up and down to control the volume.

Definitely keep up posted about what you do with them.

-Jon
 
I think i am going to interface them to a samplerate converter from AD. Ive got some samples of AD1893 wich have a S/PDIF interface needed for all the TAS50xx. Sadly (spelled wrong!?) it is not pin compatible with the AD1896!.
I think i have to make the input as a module.
But the AD1893 can upsample twice from 44.1KHz to 88.2KHz and convert 16 bit into 24 bit wich is perfect for a CD signal. You want get a odd number of oversamples wich i think maybe is important!?
If i go for a module i can implement a CS84xx S/PDIF converter or a TAS3002 (Digital Audio Processor wich is great for active speakers) or a BB S/PDIF convert (DIR1701 or 1703).
I am working a the output stage (discrete) but the powersupply!!! that is a pain. If it is bad the design will suffer a lot!.
The PWM signal from the TAS5012 is not specified so i have to check its frequency!!

Sonny
 
I just found the PWM frequency. for 88.2KHz and 96 KHz it upsamples 4 times giving 352.8KHz at 88.2KHz input.

Wich for the TAS5015 is the same! Maybe the "converter" has to be mounted on some daughterboard for later upgrades!?

It looks like the difference of the TAS5012 and the TAS5015 is in the PCM to PWM converter?

Sonny
 
Petter said:
You could use the IRF swithes that Crystal use to run their setup at 1MHz ....

Petter

øøøhhh Petter where did you find the use of IRF switches in companion with Crystal chips. I would like to see it!! :eek:

By the way i got stuck at the Powersupply. It have to be fast and have a low noiselevel. As well as a low output impedance in a wide frequency range (up to ~ 370KHz).
I wan't to be able to adjust the voltage with a dac. pheeyy! a lot of work.

If this is not okay the design will suffer a lot. ... I think i will go for a low noise ref and opamp with an output stage.

I already have a use for this powersupply (analog preamp and poweramp). So i will concentrate on this designstage.

There will be more on this subject within 2 weeks.

Sonny
 
Go to www.crystal.com and check out their digital amplifier design notes or search for IRF. Alternatively go to www.irf.com and search for Crystal.

BTW the simplest path is to get the TI eval board, solder out the 51?? and replace with say 5112, remove the 4 zero ohm resistors that short out the complementary signals feeding the 5100 output stages.

I believe the board is called 5100 eval board. There is a 2 layer reference layout for this if you want to build it yourself, ideally with discrete output.

I am hopefull that TI will come out with a ref design for the 5015 which is not secret soon. It should be close to the reference design, but you are correct that the power supply at this juncture is the most difficult part to get right. You have to modulate the power supply for volume to get the optimal results.

I would definitely go with the IRF (for Crystal) switching units since they are 1MHz switch freq. rated and matched etc. Then again, the 5100 is easy to work with if you use the reference board.


Petter
 
I cannot remember whether I did or not. Sorry.

Usually the semi companies make the dies, but wait with the mounting process for several reasons -- a) to make many at one time from order demand b) make in correct housing after they know what people want c) have no inventory themselves (rely on distributors.

It is therefore likely that they have these parts ready and that you might get evaluation chips by contacting them.

Petter
 

dc

Member
2001-12-26 9:04 pm
NYC
TI 5015 vs. Tripath

I'm on the verge of beginning to build some amps for the Phoenix dipole speakers on linkwitzlab.com. The speaker plans use an active crossover, so I'll need six channels for 2 front speakers and more later, if I decide to complete an HT setup with these speakers.

Based on what I've read, the Tripath seems like the way to go at this time. Although I haven't done the math yet, I think I can put two Tripath 0103A modules in one enclosure for 4 channels at 250W each. So two of these will support the front channels and, if I bridge one of the stereo modules, I think I can use that to power a sub.

How will the sound quality of these TI amps compare with the tripath? Are digitial crossovers really developed to a point where they, in combination with a truly digital amp (like the TIs discussed here) will be noticeably better than a good analog crossover with the Tripath? Does anyone have any information on whether/when Tripath will release the digital input they mentioned when they initially released the Tripath?

Any advice?

Thanks.

brad
 
Tripath

I don't believe Tripath are expending much effort on a direct digital to analog amp. They seem to be happy tackling the communications market. This is a shame, really, but we cannot expect Tripath to survive over time in the amp market when they go up against TI, Cirrus and other big guns.

Petter
 
TI eval module phase 1, 2 and 4

Phase 1: Replace the TAS50?? chip with a higher version -- unfortunately 5015 requires some doctoring since the input is different. Remember to delete the shorting resistors (0 Ohms) hooking up the signals to the TAS5100s

Phase 2: Replace output filter with higher quality unit

Phase 3: Set volume by changing bridge input voltage.


I am not going to try it for a while, but I might if I get access to the layout in a format that I can modify and so use the 5015 and discrete output stage with relative ease.

So little time, so much fun ...

Petter