Level shift 3v-5v for RS485

Hello
Attached is the hardware schematic for the part in discussion.

Should this work between a 3v MCU and 5v SN75176?

I am testing between 2 boards (master and slave).When i cross Rx and Tx directly,my communication works.
When i add the attached ckt i cannot communicate between the 2.
This sounds crude on my part.But someone point out anything amiss and then i will explain more on what i debugged

Thanks and regards

Why not just get a RS485 part that runs on 3v logic?
**broken link removed**

Hi Mikebits

Those chips when compared with this arrangement prove to be expensive.The link shows a price break of ~2 USD for 500 no's. SN75176 is 0.2-0.3 USD + MOSFETs and Resistors which cost negligible.Overall cost comes to ~0.5 USD against 2 USD

Can you identify any problem w/ my ckt?

abicash said:

Hi Mikebits

Those chips when compared with this arrangement prove to be expensive.The link shows a price break of ~2 USD for 500 no's. SN75176 is 0.2-0.3 USD + MOSFETs and Resistors which cost negligible.Overall cost comes to ~0.5 USD against 2 USD

Can you identify any problem w/ my ckt?

Click to expand...

hi,
Maybe something in this pdf will help.