Converting 1.8V Signal - recommend an amp to use

[ChiefPFF]

Converting 1.8V Signal

Hi there,

I'm trying to connect with an IC that uses rs232 comms.. but at 1.8V. (Only uses Rx and Tx)

I have a nice USB>RS232>TTL (5V) MAX232 style cable that I wanted to use. (5v, Rx, Tx, Gnd)

Heres how I think I need to hook them up -

PC_Rx-------------| Potential Divider 5V > 1.8 |----------IC_Tx
PC_Tx-------------| Op-Amp 1.8V > 5V |------------------IC_Rx

The Op-amp would obviously use the 5V supply from the USB cable.

Does this look right to you? Can anyone recommend a particular amp to use?

Cheers

 

[pauloynski]

Re: Converting 1.8V Signal

You can use a voltage comparator like the LM339 instead.

 

[itaig]

Re: Converting 1.8V Signal

Hi,

have a look at the SN74AHCT1G45 made by texas instruments. You can get these in a 6 pin SOT-23 SMD package and are designed to convert between logic levels.

 

[bobcat1]

Re: Converting 1.8V Signal

Hi

The easy way is to use a MOSFET conneted to boath rails with a pullup resistor

You can find an application note in TI site show you how to connect the mosfet

when you need to convert several data line (not analog) you will need to use a special IC

Many IC vendors like TI,MAXIM, ST,ON etc has converter IC for converting from one rail to another


All the best

Bobi

The microcontroller specialist

 

[ChiefPFF]

Re: Converting 1.8V Signal

Thanks very much for the help guys. After a bit more research I've gone for a TI TXB0104RGYR Translator which should do the trick. Thanks again for the pointers