Smoke rised form My ST7540 (power line carrier modem) and my ST7540 Fired!!!

[MisaghSepehr]

Hello every one;
I have bought a pair of ST7540 (Power Line carrier modem). I connected it to a host controller( AVR chip) and tried to read its internal register.
when I connected 12.5V supply to circuit, smoke rised from my ST7540 and fired!!!
after this, I checked out if my 12.5V sypply has ripple,but every thing was OK.then I looked at datasheet and found below table of pin specification:
"Vsense pin and CL pin cannot be left foating".
while I floated them!!!
signals I connected to ST7540 from host were: REG_Data , RXD , TXD , RxTx , CLR/T
and gorunded pins: GND , Test1 , Test2 , Vss , SVss , UART/SPI
and VDD was connected to VDC pin, 16MHZ crystal between X1 and X2.
Can Leaving pins Vsense and CL float cause St7540 to fail? what is the reason?
Thank you- M.R Misagh

 

[ckshivaram]

can you tell me the power supply rating of the adapter you are using for this module... check if the internal regulator is shorted.. if it new one and under warantee , i suggest you to get it replaced by the company rather than opening it your self........

 

[MisaghSepehr]

thanks for reply;
I guess I have explained my problem in wrong way.
I bought only ST7540 chip( with no waranty ) not ST7540 evaluation board and I'm sure my adapter output voltage is 12.5V with no ripples.
I just guess my chip failed because of leaving CL and Vsense pins floating while datasheet remarked that these pis should not left floating!
I want to ensure if my chip failed for this reason.because I want to try the other St7540 chip and I'm afraid if this healthy chip has a fate like the failed chip.
tnx

 

[skayravi]

thanks for reply;
I guess I have explained my problem in wrong way.
I bought only ST7540 chip( with no waranty ) not ST7540 evaluation board and I'm sure my adapter output voltage is 12.5V with no ripples.
I just guess my chip failed because of leaving CL and Vsense pins floating while datasheet remarked that these pis should not left floating!
I want to ensure if my chip failed for this reason.because I want to try the other St7540 chip and I'm afraid if this healthy chip has a fate like the failed chip.
tnx

I have designed my Circuit with Proper CL and Vsense(Not Floating). But Still my Chip got Fried.
Have You solved the problem?