SN74HCS74-Q1: Pinout Termination

Dajon McGill

Part Number: SN74HCS74-Q1

Hey Team,

If one channel is not use on the SN74HCS74QPWRQ1, how should I recommend a customer terminate the pins? Should we leave those pin floating or ground them?

Best,
Dajon McGill

over 2 years ago

0 Dajon McGill over 2 years ago

TI__Expert 5005 points

It looks like the datasheet mentions leaving the unused CMOS output pins open/disconnected. Is this recommended for all pins or just the outputs? What should I recommend for the rest?

Apologies if this is in the datasheet, I have not read it fully. Thanks for the help!

Best,
Dajon McGill

0 Emrys Maier over 2 years ago in reply to Dajon McGill

TI__Guru* 96681 points

Hi Dajon,

Unused inputs should always be terminated at Vcc or GND for any CMOS device. We have a general FAQ on the topic here: [FAQ] How does a slow or floating input affect a CMOS device?

From the section on CMOS Schmitt-Trigger Inputs:

And later in the design requirements section:

Also repeated in the layout section:

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SN74HCS74-Q1: Pinout Termination