5V to 3.3 V level shifter

[ranakashif]

hi,
I want to shift 5v signal to 3.3 v using 6n137 IC. please tell me the circuit of 6n137. Thanks in advance.

 

[barry]

The 6n137 is an optoisolator. You can put 5 volts (with a dropping resistor) on the LED side of the opto, and then use 3.3V as the collector voltage on the output side.

 

[ranakashif]

I did this but on output side there there is no voltage. can u tell me that which pin should be given 3.3v?

 

[barry]

NO pin should given 3.3 v. You need to have a resistor going from 3.3 v to the collector.

 

[spudboy488]

What kind of signal is it? If you are using an opto-coupler then that would indicate the 5V side will always drive the 3.3V side. If you do not need electrical isolation (separate grounds), just use a resistor voltage divider to knock the 5V to 3V. Probably cheaper and will consume less power.