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If the EN pin of HMC980 is used to control the power up and down of HMC980, what is the risk of too frequent switching?

1. We use HMC980 to bias the PA chip HMC943 and HMC920 to bias the PA chip HMC498. We want to switch the HMC980 (HMC920)  EN pin about 20ms according to the need, that is, to control the power up and down of PA chip HMC943 (HMC498) through the level of  HMC980(HMC920) EN pin every 20ms, is there any risk of frequent control of the EN pin?

2. How long is the response time of PA chip HMC980 (HMC920) controlled in the way of 1?That is, after controlling the EN pin, how long will the PA chip reach the normal working state?

Thanks and looking forward to your reply.

  • Hi,

    1. There's no reason you can't toggle the EN pin to power up and down the amplifiers, it shouldn't do any damage.
    2. It's hard to say how fast or slow the circuit will respond as it will depend heavily on the design itself. I would recommend testing the design in the lab to determine the speed. I will say that the control loop is not wideband, so the response isn't very fast. I think you might find that 20ms is faster than the HMC980 can reliably respond, but again, without testing your exact circuit, it's hard to say.