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Original question:

OPA615: Video clamping IC or video buffer with DC restoration function

OPA615: ZXFV4089 total replacement

Ian Draney
Prodigy 15 points
Part Number: OPA615
Other Parts Discussed in Thread: THS7316

Tool/software:

Hello!

I am updating a PCB that uses the now obsolete DIODES ZXFV4089 video amplifiers with DC restoration.  Thee ZXFV4089 accomplishes the following: DC Restoration, Sample and Hold, and Black Level Clamping.  The PCB currently uses the ZXFV4089 almost exactly as pictured in the datasheet block diagram.  The HOLD pin is controlled via FPGA.

The OPA615 datasheet shows different amplifier/buffer configurations for DC Restore (Figures 40, 41), Sample and Hold (Figure 45), and Clamped Video (Figure 44).  However, none of these appear to accomplish all three tasks in one circuit.  The best solution I've thought of to most resemble the ZXFV4089 is a modified version version of the Clamped Video diagram to more closely match the ZXFV4089 block diagram.

Is there a comparable video amplifier configuration, with or without the OPA615, that performs the same complete functionality of the ZXFV4089?

Thanks!
Ian

  • 0
    TI__Mastermind 21527 points

    Hello Ian,

    I believe you can use Figure 44 as reference and replace the ZXFV4089.  The HOLD on ZXFV4089 would be the H_CL (Hold Control) on pin 7 of the OPA615.  The V_REF of pin 11 maps to the REF (pin 3) of the DIODES part, and you can use the passives to construct the remaining circuit.

    I do acknowledge the DIODES IC does appear to integrate a few of the necessary routing choices and potentially passive components, but the OPA615 is likely the best option unless you want a full-featured video amplifier with DC restore and integrated filtering. Those devices are the THS73xx family of video amps, such as THS7316.

    Best,

    Alec