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# SN74AVC4T774: About typical Data Rate at “From 2.5V to 1.8V Translation”

Part Number: SN74AVC4T774

Hi Team,

Our customer would like to know the typical Data Rate at “From 2.5V to 1.8V Translation”.

We guess that this value is more than 380Mbps.

Because tPLH and tPHL at “From 2.5V to 1.8V Translation” is smaller than “From 1.8V to 3.3V Translation”.

(So, I understand that the typical Data Rate depends on tPLH and tPHL.)

Is my understanding incorrect?

If no, could you please let us know this value?

Regards,

Kanemaru

• Hello Kanemaru-san,

Translation to 1.8V is clearly stated on the front of the datasheet as 200 Mbps typical.

Your question is deceptively complex. Data rates are not linked directly to propagation delay.  The propagation delay says how long it will take for an input change to show a response on the output.  The data rate describes the device's ability to reproduce a signal within all of the datasheet specs (output current, output voltage, maintained across temperature, voltage, and process).

For example, a 200 Mbps signal has a pulse width of ~5ns.  For your case, the propagation delay at VCCA = 2.5V and VCCB = 1.8V is 3.2ns max.  If you input a 2.5-V, 100-MHz square wave (200 Mbps) to the SN74AVC4T774, the output will be a 1.8-V, 100-MHz square wave that will be slightly delayed from the input.

If you attempt to drive a faster signal through the device, it will likely continue to function, ie it will still produce a square wave at the output, however the output voltage min/max, the drive current, and the delays might not meet the datasheet specifications any longer.

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• In reply to Emrys Maier:

Hi Emrys-san,

Thank you for the detail information.

I understand. Thank you very much.

Regards,

Kanemaru