SN74AXC1T45: About the maximum frequency of the clock in case level translating from 3.3V to 1.1V

Takamaru Akita

Prodigy 140 points

Part Number: SN74AXC1T45
Other Parts Discussed in Thread: SN74AUC1G125

Hi team,

We are going to use SN74AXC1T45 to translate voltage level of the clock, from 3.3V(VCCA) to 1.1V(VCCB).

The maximum frequency of the clock is 27MHz.

Q:Is this all right? If there is any concern about this translating condition, please let me know.

In the datasheet, we couldn't find the maximum frequency(datarate) in case translating from 3.3V to 1.1V.

So we have estimated the maximum frequency from the propagation delay.

[Datasheet p10, VCCA=3.3V, VCCB=1.2±0.1V : tpd=7ns]

(Maximum frequency of the clock)=1/(2tpd)=71.4MHz

Thanks

Best Regard

Akita

over 3 years ago

0 Clemens Ladisch over 3 years ago

Guru 243820 points

This is a safe way of estimating the maximum frequency.

Please note that unidirectional downtranslation can be done with a buffer with an overvoltage-tolerant input, e.g., SN74AUC1G125, which is cheaper and faster than the AXC.

0 Takamaru Akita over 3 years ago in reply to Clemens Ladisch

Prodigy 140 points

Hi Ladisch,

Thank you for your reply and more information!

I'll close this thread.

Thanks

Best Regard

Akita

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SN74AXC1T45: About the maximum frequency of the clock in case level translating from 3.3V to 1.1V