SN3257-Q1: SN3257-Q1 pull-up/pull-down when input is disconnected

Jonata Ubbiali

Part Number: SN3257-Q1

Hello,

I'm using this component to connect two different SPI devices (Device A on SxA pins and Device B on SxB pins) to one SPI net (on Dx pins).

Device B can be phisically disconnected from the switch.

Question: are needed pull-up or pull-down resistors on the SxB pins of the switch?

Thanks in advance for your feedback

Best Regards

Jonata

4 months ago

0 Nir Gilgur 4 months ago

TI__Expert 7115 points

Hello Jonata,

Yes, I recommend connecting pull down resistors to the floating pins in a case where Device B disconnects from the switch. Please use 50ohm termination resistors to avoid the possibility of noise coupling to the floating inputs and introducing crosstalk into the multiplexer which can cause fluctuations on other inputs and outputs on the device itself.

Thanks,

Nir

0 Jonata Ubbiali 4 months ago in reply to Nir Gilgur

Prodigy 120 points

Hi Nir,

thank you very much for your advice.

Best Regards

Jonata

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SN3257-Q1: SN3257-Q1 pull-up/pull-down when input is disconnected