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THS3120: Excessive heating

A T Rajesh Kumar
Prodigy 140 points
Part Number: THS3120

Hi,

I recently built an analog buffer board using this IC. Please find attached the schematics. After I power up, I am observing that the op-amps are getting excessively heated up. I am observing this heating even when there is no cable/load attached to the output of the op-amp. Is there anything I can do in the circuit (in addition to layout) to prevent this.

regards,

rajesh

THS3120_single_supply_2outputs.TSC

  • 0
    TI__Genius 15975 points

    Hi Rajesh,

    I believe the second stage THS3120 circuit is oscillating because its output (OUT) is directly connected to the inverting input (IN-). The THS3120 being a current feedback amplifier, you should not directly short the output to the inverting input because its stability is determined by the feedback resistor or Rf value. I would recommend using an Rf = 802-ohms across the feedback path from OUT to IN- in-order to make the THS3120 stable and re-check as to whether there is no more of the heating issue.

    Best Regards,
    Rohit

  • 0 in reply to Rohit Bhat
    Prodigy 140 points
    Hi Rohit,

    Thank you for the great suggestion! It has greatly reduced the heating. The second-stage op-amp (U1) is now as cool as room temperature!

    thanks and regards,
    rajesh