3.3V driving 5V digital. how??

[silver_sparrow]

What device do I need to help interface 3.3V digital output
to 5V input on CPLD???

I just have 3 signals to interface, with max freq of operation at 75MHz.

I would like to be able to buy the component from Digi Key.

Sparrow

 

[gorkin]

Logic Compactibillity

Hy, try the single configuration called inverter with single transistor and resistr, its funny and work very well.
Gorkin

 

[E-design]

Use a level translator. Maxim have a few products. If the speed is not high enough you may need to build something with discrete components

**broken link removed**

E

 

[btbass]

Use SN74LVC3G07 which is an open collector 3 gate buffer from Texas.
Can work on voltage 2V6 - 5.0V. Ideal solution.
8)

 

[it_boy]

If it is just for inputs meaning, if you are not required to connect the 5V output of CPLD to the 3.3V device, do you really have to use a level translator?
I think 3.3V will still drive a high on the TTL input pins.

 

[my_garden]

Which type CPLD are you use?
Now may 5V cpld can be drived by 3.3V

 

[Divemen]

Have a look at TI.

Interfacing the MSPxx device(3 V) to TTL.
There are a examples.

**broken link removed**


Divemen

 

[Gorilla]

I agree with it_boy and my_garden. Just look at the output and input specs of your device. For most CMOS CPLD inputs, > 2.0V means 'high'. So if your 3.3V output comes to say 3.0-3.1V, there is no need for level shifters.

I think you'll find the same in the TI document Divemen pointed out.

 

[silver_sparrow]

thnx for the responses, it was nice to share ideas on this.

the cpld is a -Al ter a- Flex10K.

-- one signal does not reach 3Vpp to the scope, that is why I wanted to
level shift before feeding.

I shall try to use a buffer to compensate from TI.

sparrow