I am struggling using the HMC729 on an EVAL board for the first time, and was directed here by an AD staff applications engineer. I would like to recreate the timing diagram shown on pg. 4 of the HMC729 datasheet. Here is what I have setup and a scope trace is shown below:
Power: -3.3V, drawing 80mA
RN, CN, QN: left floating (really internally grounded through 50ohms)
RP: Held at -0.5V
CP: shown on scope trace C4, input from a function generator, 100kHz square wave, +250mV to -250mV
QP: shown on scope trace C3, output terminated with 50ohm
I have an expectation that the output should essentially be an identical square pulse with twice the period of the input. However, QP switches state randomly, and also has noticeable 'blips' upon every state change of CP. Any ideas what I'm doing wrong? Is it likely that I damaged the chip?
