SN54SC6T17-SEP: Is It Suitable for Cold Sparing?

Rob Weinstein

Part Number: SN54SC6T17-SEP

Hello,

Are there any adverse effects if I disable VCC to the SN54SC6T17-SEP while its inputs are still being driven from, e.g., an FPGA? Is there a difference if I just leave VCC open vs. tying VCC to ground?

Thanks,

Rob

4 months ago

+1 Clemens Ladisch 4 months ago

Guru 267550 points

This is allowed; see [FAQ] Can the input voltage (Vi) to my logic device be higher than the supply voltage (Vcc)?

0 Rob Weinstein 4 months ago in reply to Clemens Ladisch

Prodigy 50 points

Hi Clemens,

Thanks for pointing me to that FAQ, now I have a more complete picture:

The SN54SC6T17-SEP doesn't have positive input clamp diodes so VI(max) "can be applied to the input of the device without damaging it, regardless of the value of Vcc." [1]
The SN54SC6T17-SEP doesn't have "Ioff - Partial Power Down Protection" but it wouldn't apply to the device inputs anyway because Ioff "only applies to input circuits with bus hold because non-bus-hold devices do not have p-channel drains or sources directly attached to the input pin." [2].

Thanks,

Rob

[1] [FAQ] Can the input voltage (Vi) to my logic device be higher than the supply voltage (Vcc)?
e2e.ti.com/.../faq-can-the-input-voltage-vi-to-my-logic-device-be-higher-than-the-supply-voltage-vcc

[2] Logic in Live-Insertion Applications with a Focus on GTLP
www.ti.com/.../scea026.pdf

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SN54SC6T17-SEP: Is It Suitable for Cold Sparing?