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LMH6517: Are there any restrictions to operating the LMH6517 with DC coupled inputs?

Part Number: LMH6517
Other Parts Discussed in Thread: LMH6882, LMH6521

All the circuit examples in the LMH6517 data sheet and the associated Eval board documentation seem to show ac coupled inputs using capacitors or balun transformers.

In our application, we must use DC signal coupling at the LMH6517 VGA inputs.

Data sheets for other similar TI VGA devices such as LMH6882 specifically mention DC coupling of their input signals but LMH6517 does not, so I thought I should ask E2E.

Other electrical restrictions: - for example, by how much do we need to limit the current applied to LMH6517 inputs during any signal input overshoots?

Thanks

Ed Phaneuf

  • Hello Ed,

    Here is a reference design on how to do this for the LMH6521:

    The same concepts will apply to this device, as it also features a self-biasing feature to 2.5V.

    In regards to signal overshoot, I would confirm that you are not exceeding the abs max input voltage spec of V+.

    Best,

    Hasan Babiker