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THS4521: Shutdown

Part Number: THS4521
Other Parts Discussed in Thread: THS4551, , OPA837, THS4561

What does it do when shutdown? All it says in the datasheet is that it goes into a low power mode.

Do the output go high-impedance? So it could be left with the outputs connected to another part of the circuit without affecting it?

  • Good question Ian, 

    yes, really the only spec is the lower supply current - the signal path is still present through the external resistors but the I/O pins see powered down transistors - enough input signal might turn them on, hard to say and not modelled in the TINA file. 

    Keep in mind the THS4551 is a significant upgrade to the THS4521. Much better noise, DC errors, harmonic distortion, etc etc etc. 

  • So not quite so useful as it seemed at first glance! Applicable only to power saving, not a neat way of multiplexing outputs.

    the THS4551 may be marvellous, but it’s in a fiddly package, and difficult to get:

    RS just sends me straight back to the THS4521, and Farnell Only has the VQFN, which isn’t so bad to deal with, but it’s much easier to probe a SOIC!

  • I don't think the wired-or mux function you are describing exists in an FDA, you might look at the OPA837 which specifically will support that, 

    The THS4551 is in the MSOP-8 package, not sure what you mean fiddly or hard to get, 

    The noise is better on the THS4551, top 3 here are voltage noise, bottom 3 or current, the THS4561 might have changed from what I show here,