Gentlemen:
I have an application where I just need a 920 MHz fixed sine wave oscillator output. A square wave would be acceptable also, since I could just filter it into a sine wave. I have used many oscillators in the past, but never at this high a frequency. No one seems to carry crystals that high, though they do have oscillators. The oscillators they have are all differential-pair output. I'm used to oscillators that you just apply voltage to and you get a wave out.
I tried one of these oscillators with an LVDS output. The only LVDS receivers I can find at that frequency are monstrous ones like a SN65LVDS314. I tried a high-speed comparator like an AD8561, but I get no output at all.
I also tried a high-frequency VCO and set the "tune" input with a voltage divider, which apparently doesn't work either. I even found a sample circuit on the Maxim website for the exact chip and it was nearly identical to what I had:
But when I connect it to 3V, nothing happens. The trace on the scope doesn't even flinch...totally dead. I tried two different MAX2623 chips and neither worked. I double-checked all my wiring. I must be doing something stupid with all this.
Isn't there a simple way to get a usable 920 MHz sine wave?
Don
I have an application where I just need a 920 MHz fixed sine wave oscillator output. A square wave would be acceptable also, since I could just filter it into a sine wave. I have used many oscillators in the past, but never at this high a frequency. No one seems to carry crystals that high, though they do have oscillators. The oscillators they have are all differential-pair output. I'm used to oscillators that you just apply voltage to and you get a wave out.
I tried one of these oscillators with an LVDS output. The only LVDS receivers I can find at that frequency are monstrous ones like a SN65LVDS314. I tried a high-speed comparator like an AD8561, but I get no output at all.
I also tried a high-frequency VCO and set the "tune" input with a voltage divider, which apparently doesn't work either. I even found a sample circuit on the Maxim website for the exact chip and it was nearly identical to what I had:
But when I connect it to 3V, nothing happens. The trace on the scope doesn't even flinch...totally dead. I tried two different MAX2623 chips and neither worked. I double-checked all my wiring. I must be doing something stupid with all this.
Isn't there a simple way to get a usable 920 MHz sine wave?
Don