SN74HC368: Clamp Diode Structure

user5163865

Part Number: SN74HC368
Other Parts Discussed in Thread: CD74HCT368, SN74AHC540, SN74LV540A

Hi,

What is the VF of the input ESD protection diode?

The customer's circuit may apply the input when the power is turned off.
Customers should consider the CD74HCT368, but before doing so, evaluate the condition of the HC368.

Best regards,

Hiroshi

over 2 years ago

0 Clemens Ladisch over 2 years ago

Guru 244220 points

It's a plain silicon diode (so about 0.7 V for small currents), but its characteristics are not guaranteed.

A current will flow into V_CC and might partially power up any devices connected to it, so this is usually not what you want.

I'd recommend a different device with overvoltage-tolerant inputs, e.g., SN74AHC540 or SN74LV540A. (There is no pin-compatible device.)

0 user5163865 over 2 years ago in reply to Clemens Ladisch

Genius 3335 points

Clemens-san,

Thank you for your answer.

Best regards,

Hiroshi

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SN74HC368: Clamp Diode Structure