HMC980 vs HMC981

Hi Mateus Ohse ,

The startup sequence illustrated in the datasheet should be followed to avoid damage to the ABC. The reverse order should be followed to power down the ABC. Can I ask why you are testing the ABC in this way? What is your end application?

Thanks,

DanO

Hi Dan,

With the HMC980, what I am experiencing is that if I follow the power-up sequence from the datasheet, it does not start:

I actually have to apply VDD prior to VDIG for it to start.

And then looking at HMC981 datasheet, the Power-up waveform is VDD first and then VDIG:

And also, the EN pin on HMC980, is causing it to latch, while it's working as indented on HMC981.

Can I ask why you are testing the ABC in this way? What is your end application?

Just doing some basic DC bench checks, before I connect it to an amplifier.

Cheers,

I would suggest connecting the ABC to an amp and following the recommended bias sequencing.. I suspect that the bias sequencing will work with an active amplifier in line (remember to reverse for power down).

I would suggest connecting the ABC to an amp and following the recommended bias sequencing.. I suspect that the bias sequencing will work with an active amplifier in line (remember to reverse for power down).