Schmitt trigger input with 5v to 3.3v level shift

Wayne Mayes

Prodigy 20 points

Other Parts Discussed in Thread: SN74LVC1G17

Hi,

I'm looking for a single bit Schmitt trigger input device.

Inverter or buffer will work

Input signal is a pulse up to 2 megahertz open drain with a 220 ohm pull-up resistor to 5 volts

Output required is a clean 3.3 volt pulse to drive the input of an fpga.

Many years ago I used a 74hc14 plus sn74cbt3384 but I would like to update to a single chip single channel solution.

Thank you,

Wayne

over 5 years ago

0 Clemens Ladisch over 5 years ago

Guru 316780 points

You want a buffer with an overvoltage-tolerant input. The search function finds the SN74LVC1G17.

0 Wayne Mayes over 5 years ago in reply to Clemens Ladisch

Prodigy 20 points

Hi Clemens,

Thank you for responding so quickly!

I did see the SN74LVC1G17. I was concerned that if I connect vcc of that chip to 3.3 volts to get the correct output that the input voltage thresholds would not be very suitable for the 5 volt signal.

Thank you,

Wayne

0 Clemens Ladisch over 5 years ago in reply to Wayne Mayes

Guru 316780 points

It's OK if the signal's low level is below 0.89 V.

Logic

Logic forum

Schmitt trigger input with 5v to 3.3v level shift