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Short pulse width signal amplifier

Linqing Luo
Prodigy 10 points
Other Parts Discussed in Thread: THS3201, THS3091

We are looking for a kind of amplifier that can amplify a pulse signal with 10 ns pulse width and 10 us period. The amplified signal should have 6.5V peak voltage (1.8V before amplified) when the pulse is "on" and ideally 0V when the pulse is "off".The rising time and falling time should be as low as possible. Could anyone give suggestion on how to choose the IC and devices to achieve the job?

  • 0
    TI__Genius 12631 points

    Hello,

       With a 10ns pulse width, I will assume that the minimum rise/fall time you are willing to deal with is 1 ns. This will then give you a minimum required gain-bandwidth of 0.35/1ns = 350MHz..

     Your gain requirements are 6.5V/1.8= 3.6V/V

    This puts your gain BW requirement as 3.6 * 350 MHz = 1.26GHz..

    However you are looking at large signal BW rather than small signal BW. Alternatively, you are looking at a part with a slew rate of at least 1000V/us.

    I think with the above (minimum) requirements, an opamp with a Current Feedback Architecture will best suit your needs. The main advantage of a CFA is that they dont have the same Gain-Bandwidth relationship that traditionsal Voltage FB opamps have. The THS3201 looks like it could meet your needs. It doesnt quite have the +/-6.8Vpp requirements that you need.

    If the swing requirements are more crucial then the THS3091 may be your next best choice. It has larger signal swing but lower speed.

    -Samir