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AD9434-FMC-500EBZ component designators mix-up

Question asked by j.marjanovic on Aug 27, 2016
Latest reply on Aug 30, 2016 by RReeder

Hi,

 

during the development of an FPGA application with the AD9434-FMC-500EBZ evaluation board I wanted to speed up the SPI interface by changing the series termination resistors on SPI lines (R2 and R3). The current value of 1k seems to be to high, resulting in very high rise time and consequently in low maximum achievable frequency (around 1MHz).

 

There are 3 resistors on the board right next to 9-pin jumper (P400). The designators seems to indicate that the SDIO line resistor (R3) is the outer-most one, while in reality is the middle one. I have verified this with an oscilloscope, and the order of components can also be checked in 20_a03471a-ipc356.ipc file from ad9434_fmc_gerbers_wiki.zip archive (note the ascending X position):

 

327m0022            R2    -2          A01X+018900Y-011788X0275Y0250R270 S1      
327m0021            R3    -2          A01X+019350Y-011788X0275Y0250R270 S1     
327AVDD_DUT         R4    -1          A01X+019800Y-011788X0275Y0250R270 S1     

 

I would appreciate a warning on the schematics, I accidentally burned the output driver of U401 (ADG3304BCPZ) on the board.

 

Best Regards,

Jan

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