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TIPD108: 5 MHz Triangular wave for PWM

Farhan Nasir
Prodigy 50 points
Part Number: TIPD108
Other Parts Discussed in Thread: TLV3502, OPA2365, TLV1832

Tool/software:

Hello TI,

I want to generate a 5 MHz bipolar triangular waveform with an 8V peak-to-peak amplitude for PWM. Is this reference design compatible with a 5 MHz triangular wave? Thanks

Best Regards

Farhan

  • 0
    TI__Genius 11745 points

    Hi Farhan,

    I'll be referring to this circuit specifically from the reference design.

    You will need to adjust the devices. OPA2365 and TLV3502 are 5.5V devices. TLV3502 is not able to handle the +-4V rail and a 8Vpp swing at its input. TLV1832 is a dual 40V 65-ns comparator that you might be able to use in this reference design. However, a 5MHz triangle wave has a period of 200ns. Per the "Comparator Selection" section on TIPD018, 65ns > 200ns/10 and may result in the propagation delay having a non-negligible effect on the feedback loop.

  • 0 in reply to HO SIU
    Prodigy 50 points

    Hello.

    Thanks for your reply. Do i also need to change OPA2365 for getting 8Vpp?if yes can you suggest replacement. Thanks

    Farhan

  • 0 in reply to Farhan Nasir
    TI__Genius 11745 points

    Hi Farhan,

    I'll go ahead and assign this post to the high-speed amplifiers team. They will be able to assist you with device suggestions.

  • 0 in reply to Farhan Nasir
    TI__Genius 16845 points

    Hi Farhan,

    I was able to look over the application and filtered for FET input devices that meet the bandwidth and slew rate requirements. However, like was previously mentioned I do believe the comparator will be the limiting factor by trying to get the larger output Vpp signal. One option would be to create a small Vpp signal so that you can use the faster comparator device and potentially gain the triangle wave to the desired Vpp value in a following stage. 

    High-speed op amps (GBW ≥ 50 MHz) product selection | TI.com

    Best Regards,

    Ignacio