Question about HMC349AMS8GE

Question

Hello, 
 
 My customer us deciding to use HMC349AMS8GE to their project. 
 And during the component test, they find some issue. 
 So they need your advice about the operation of HMC349A (RF switch). 
 
 Please refer below questions and let me know your answers. 
 
 1. Test condition and phenomenon 
 1-1). Switching RF1 to RF2 without RF input signal. 
 And measure the output voltage of RF2

2-2). When they measue the voltage of RF2 pin at switching moment, they can get Vpp 1.84V occuring short time like below capture file.

3-3). Circuit of HMC349A

2. Questions 
 2-1) At above test, would you let me know your opinions about Vpp voltage which is occurred at RF2 (output) pin? 
 2-2) Can HMC349A be dameaged by Vpp 1.84V? 
 2-3) At other RF switchs, is this Vpp occurred? 
 
 Regards, 
 Sewoong

yus · Accepted Answer

This phenomenon is called video feedthrough. Other RF switches have also similar behavior. However, we don't expect it to be 1.85V.
I measured one of our eval boards when RF ports are 50 ohm terminated and video feedthrough is ~30 mVpp

Do RF pins are terminated during this measurement? You'll measure significantly larger DC jump if path is left un-terminated.
I suggest repeating this measurement with other HMC349A as well before further investigation.

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