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THS4541: Impedance between FB pin and output pin

haruki okumura
Prodigy 60 points
Part Number: THS4541

Tool/software:

添付図のように、入力抵抗200Ω、FB抵抗200Ωを接続した回路を作成しました。ゲイン設定は1倍です
が、実際に測定してみるとゲインは1.04倍でした。FB
ピンと出力ピンは同じ電位になるはずですが、そうではなく、出力ピンの電圧はFBピンの1.04倍になっています。

FBピンと出力ピンを短絡してみたところ、ゲインは設定通り1倍になりました。

添付の図に示すように、FB ピンと出力ピンに 8Ω が接続されているようです。

複数の回路でこの現象が確認されました。
これは部品の仕様でしょうか、それともロット不良でしょうか？

  • 0
    Prodigy 60 points

    I posted this in Japanese, so I will repost it in English↓

    I created a circuit with an input resistor of 200Ω and a FB resistor of 200Ω connected, as shown in the attached diagram. The gain setting is 1x.
    However, when I actually measured it, the gain was 1.04x.
    The FB pin and output pin should be at the same potential but this is not the case and the voltage of the output pin is 1.04 times that of the FB pin.

    When I tried shorting the FB pin and output pin, the gain was 1x as set.

    As shown in the attached diagram, it appears that 8Ω is connected to the FB pin and output pin.

    This problem was confirmed in multiple circuits.
    Is this a part specification or a defective lot?

  • +1 in reply to haruki okumura
    TI__Mastermind 24630 points

    Hello Okumura,

      Closing this thread, and we can continue discussion at this e2e thread: e2e.ti.com/.../ths4541-impedance-between-fb-pin-and-output-pin