Hi,
HIGH level 1.4V ... 2.1V is valid for both ICs.
I thought about this idea, however, I was worried a divider which produces 1.6V (2K and 1K) would be cutting it close for the 1.4V minimum for the ADF5901. Assuming worst case, and my resistors are 10% off, 2200 and 900, that would very close to 1.4V. I suppose I could make a divider using different resistors, but the point was to reduce everything, from cost, area, and parts on BOM.
Thanks for the advice!
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I would be a little concerned about capacitance. What speed are your signals? Driving into the RC formed by your 1Ks might be a problem. Also, verify that your uC can drive a 3K load.
The u-controller is the Atemga328p. The max I/O current is 40 mA, so I assume 5/3 mA should be OK?
Regards to the RC, never considered that. One major problem, I am relying on 3rd party software (Arduino) to do the actual SPI communication. So, other than specifying a communication speed, 20 MHz, I am flying blind. What I do know, the input capacitance to the ADF chips is 10 pF. Worst case 2K in series 10 pF, 20 ns (50 MHz). 50 MHz is faster than 20 Mhz (rather the delay is shorter than communication speed), is that what I should worried about?
bonus help:
As I mentioned, I am relying on other people's software to write to the chips, so the timing diagram is somewhat a mystery to me. I've spent a little time looking, but what is the unit (ns min)? Google keeps giving me ways to convert nanoseconds to minutes
Thanks again!
Both you and KlousST are impeccable human beings