I'm using a HMC835LP6GE PLL on one commercial FMC mezzanine board (Vadatech FMC225) and I have a question regarding the Power Down Mode. As described in the datasheet, pulling pin CEN (17) low will power the chip down, but serial port should still respond to the normal communication (section 1.5, not taking into account possible SPI override). There is no pin CEN and pin 17 is GND according to the pin descriptions earlier in the same datasheet. On the other hand, there is a pin CHIP_EN (25) which (when pulled low) powers down whole chip even with the serial line (this is how my board behaves).
Can you please clarify the real/intended behaviour of the CHIP_EN pin?
Thank you very much,