Hi
We are using SN74CBTLV3245APWR as level translator in one of our project. We need the following values for this IC.
1)Voh,Vol,Vih and Vil values for A side as well as B side.
2)Ioh,Iol,Iih and Iil values for A side as well as B side.
Thanks and Regards
Dibin Mathew
Hi Mathew
This part is simply a switch and there is no Vih/Vil Ioh/Iol.
what goes in on one side comes out the other.
The CBTLV will not level translate. Let me know what you are trying to do and I can help you choose the right part.
Hi Chris,
We got two application note regarding how FET switches can be used as a level translator. The application notes are scda006 and scea035a.
Plz let me know the device which we have selected can be used for level translation.
We have a lot of different kinds of switches. some can be used for translation some cannot.
The appnotes you refer to show a N channel FET type switch that will have the inherent 1V VT drop.
There are other switches where we modified the parts to where the output level will equal the input. these include CBTLV and CB3Q families. these two families are not suited for translation.
The CBT and TVC family can be used for translation as shown in the appnotes. You can use the SN74CBT3245A or SN74CBT3245C instead.
Thanks for the reply.
Can u plz provide us the Voh,Vol,Vih,Vil,Ioh,Iol,Iih,Iil values for SN74CBT3245APWR.
Hi Mathew.
These parts are still simply switches. They will have no drive. There will simply be a connection from the input to th output. The input can take any level up to 5.5V and the out put will equal the input. For the CBT device the output can only rise to Vcc-1V . any signal less than Vcc-1V will simply pass through.
If you need a part hat can buffer or have drive (ioh Iol) then you will need to use a duel voltage level tranlator.
The CBT3245 is a N channel FET. The output will only go to Vcc - 1V. Then as show in the appnote you will drop the Vcc another Vt by adding the series diode in the Vcc line.
The VT drop + the 1V drop of the CBT device will only allow the output to be 3.3V. so with a 5 V input you can drop the voltage to 3.3V.
I attached a translation appnote.
We are using the switch for translating 3.3V to 1.5V (unidirectional). Whether pull up resistor of 150ohms at 3.3V side is required for down translation?
The resistor will not be needed on the 3.3V side.
You could also just use a buffer that is overvoltage tolerant on the inputs. SN74AUC244 you cuold set VCC at 1.5V and the input could be 3.3V. The part would translate down to VCC and also have buffering. The only issue with this part is a limited type of packages.