The top-secret new Qualcomm or the old Zetex D

[IVX]

CSRA6620 looks promising, and unlike Zetex this one is a single-chip solution.
As I see I can buy CSRA6620 for about $5 from Arrow, however, Qualcomm makes from that chip a military-like secret. Any ideas?
Documentation | CSRA6620 | Qualcomm

 

[drMordor]

Hi IVX!
Very interesting chip.
To access the documentation, you need to be a company and sign an NDA

 

[IVX]

not only, they simply refuse your request if you are not big enough. I did ask some US company to help me to get app info but Qualcomm refused their request as well.

 

[dreamth]

all good things in life are for free .

 

[drMordor]

Can you make a request via Arrow?
Order a chip and ask for a datasheet?

 

[kipman725]

Qualcomm are not an ethical company, be cautious in dealing with them.

 

[IVX]

drMordor, so just to pay for $6000 Arrow and get 1KU of CSRA6620, next praying for pdf? Nice ))
Actually, I suspect CSRA6620 not so good as we can expect. Seems THD+N at 6kHz .01%, and no any details regarding the load used.

 

[stuartlew]

Here's the data sheet for CSRA6620 board ? maybe.

Look for the 1.22mb attachment link near bottom of page. Full Range Amp with Switching Power | Taiwantrade.com

 

[IVX]

stuartlew, ok but there are no more details that Qualcomm gave in thier breif. I would like to see THD vs power sweep, and THD vs frequency sweep at -3db and -20db, Zout vs freq. I can see in the pdf you reffered that SNR(-105db or -108db(A)) and THD+N(.01%@1kHz@-3db, perhaps close to .1% at 6.3kHz) noticeable worse than Quallcomm promised.

 

[KaffiMann]

noticeable worse than Quallcomm promised.

But it's also a very different layout from the evaluation module, impossible to say for sure.
The Taiwantrade board also has onboard PSU.

Shame the evaluation kit is so pricy (800$), most developers will probably prefer the TAS3251 since that eval kit is only 249$ and it has more features(?).
https://www.ti.com/store/ti/en/p/product/?p=TAS3251EVM

 

[Reactance]

Interesting controller. Made mostly to save BOM cost, nothing a x1 32bit MCU and x2 IRS2093MPBF cannot do.

I can only imagine what that meeting looked like when the engineering R&D group pitched it to the black suit in the meeting room. This is purely made for high high "volume" customers , Qualcomm is not in the business dealing with us small fry.

 

[drMordor]

Denon PMA-60 use this chip.
I have full service manual.

 

[KaffiMann]

Wow! The Denon PMA-60 is very expensive for what it is.
Local price 697 USD! w0000t?!

 

[IVX]

Denon PMA-60 use this chip.
I have full service manual.

thank you for the input, however, it is far not enough without internal registers description. As I see, the chip actually doesn't take FB from the output directly, only like a mix before/after output filter. I have tried Ti TPA3251 with similar "FB after LC", that chip shows about Ok THD at the resistor load but at the real speaker load THD drops to .05% anyway even at 1kHz + awful clipping.

 

[timc995]

for what it's worth, the CSRA6620 is the chip used in the Sonos AMP (not the older Connect:AMP, but the one introduced in ~ 2018)