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SN74AVCH1T45: The output termination of SN74AVCH1T45

long yong

Prodigy 20 points

Part Number: SN74AVCH1T45

Tool/software:

Hi,

I have a question about the output termination of SN74AVCH1T45, my input signal is a 3.3V 100MHz LVCMOS and i want to translate it to 1.8V LVCMOS, however i don't find the output impedance of the chip in datasheet, should i put a series or shunt resistor to match the 50ohm transmission line? the 1.8V signal is sent to the CLK pin of FPGA.

0 Michael Ikwuyum 4 months ago

TI__Mastermind 29775 points

Hi Long,

Yes, you may use a 0 ohm series resistor for the 1.8 V outputs and adjust up to 33 ohms per your system needs, thanks.

Best Regards,

Michael.

0 long yong 4 months ago in reply to Michael Ikwuyum

Prodigy 20 points

Thanks for your reply, so i have another question: what's the impedance of the input and output port of SN74AVCH1T45？

Best Regards,

Long.

+1 Michael Ikwuyum 4 months ago in reply to long yong

TI__Mastermind 29775 points

Hi Long,

Input is high impedance i.e. R = Vcc / Ii.

Output impedance while driving high = (Vcc-Voh) / Ioh and Vol / Iol while driving low, thanks.

Best Regards,

Michael.