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AMC7834: Will the AMC7834 worked in pulsed RF applications?

Terry Noe
Prodigy 20 points
Part Number: AMC7834
Other Parts Discussed in Thread: LMP92066

In my application, I need to control the bias of a poweramp in a pulsed RF application.  The nominal bias current is high (9A) when the RF is on, and basically zero when the RF is off.  The width of the RF pulse is 4 microseconds.

It seems like the AMC7834 could work in this application if:

1) The response time of the current-sense amplifiers is fast enough to respond to a 4us current pulse

2) If the ADC is fast enough: If the sampling time of the ADC sample and hold is less than 4 us.

I cannot find answers to either question on the datasheet.  Thanks in advance for your help,

Terry

  • 0
    TI__Guru 52663 points

    Hi Terry,

    1. 4us is likely too short for the clamp functions of the AMC7834.  The typical switching time might prevent this:

    2. The AMC7834's ADC minimum sample time for the current shunt in closed-loop operation is 200us.  

    I think you would be better served with the LMP92066, which integrates output switching.  This device does not use current monitoring, but rather temperature monitoring for compensation.

    If you would like to tell me more about your application, feel free to email me at frost@ti.com. 

    Thanks,

    Paul