Other Parts Discussed in Thread: LMX2487, LMX2487E, , USB2ANY
Hi Y'all,
Because the LMX2485E eval board is discontinued, I tried following a previous forum thread (https://e2e.ti.com/support/clock-timing-group/clock-and-timing/f/clock-timing-forum/692146/lmx2485e-evm-availability/2560693?tisearch=e2e-sitesearch&keymatch=LMX2485#2560693) to take off the LMX2487 PLL chip and replace it with the LMX2485 PLL chip on the LMX2487 Eval board. I also replaced the different resistor and capacitance values in the manual to make the LMX2487E into the LMX2485E (page 10 of https://www.ti.com/lit/ug/snau137b/snau137b.pdf?HQS=dis-mous-null-mousermode-dsf-pf-null-wwe&ts=1657585772198&ref_url=https%253A%252F%252Fwww.mouser.com%252F). A kludged, LMX2487-to-LMX2485, older (2012) board version works in controlling an external synthesizer at 190 MHz, which makes sense because we do not use the crystal VCO that is rated for a higher frequency. However, the 2017 newer eval boards do not work. The PIN layout to communicate with the computer looks different, and I was wondering if there is something that had to be changed with the newer LMX2487E board versions or if the usb2any connection is different?
Maybe I'm crazy and something else is wrong, but I wanted to get an expert opinion before I delve any further.
Thanks,
Jose
