SN74CB3T16210: Can that device convert for sure 3.3v to 2.5v ?

Ohad Fundoianu

Part Number: SN74CB3T16210

Hi,

This device is announced to enable 3.3v to 2.5v shifting.

According to its datasheet, the level shifting is done as described in the following picture (taken from the datasheet):

According to what said above, if I want to get VOH=2.5v I need to connect VCC=2.5V since "The output high voltage (VOH) level will be equal to approximately the Vcc voltage level".

On the other hand, it is said that to get VOH=VCC, the VIH level be greater than or equal to Vcc+1v and less than or equal to 5.5v which means :VIH>=Vcc+1v=3.5v.

So if VIH shall b bigger than 3.5v (VIH>=3.5v) in order to get VOH=2.5v than how can that Level shifter make it for VIH=3.3v or little bit less (DC drop till the device) ??

over 5 years ago

0 Adam Torma over 5 years ago

TI__Mastermind 45340 points

Ohad,

What type of signals are you attempting to level shift? What type of devices are you connecting that you need to translate 3.3V to 2.5V? Do they have open drain drivers or push-pull drivers? Do you need to do bi-directional communication?

Why did you choose the SN74CB3T16120 instead of a level shifter like the SN74AVC20T245?

Thank you,
Adam

0 Ohad Fundoianu over 5 years ago in reply to Adam Torma

Intellectual 540 points

Hi,
I would be very grateful if you could recommend me on a n LVCMOS clock buffer/driver 1:20 - 1 input to 20 outputs, powered by 2.5v and 3.3v tolerant ?

Thanks,

0 Adam Torma over 5 years ago in reply to Ohad Fundoianu

TI__Mastermind 45340 points

Ohad,

I'm going to move this thread to the clocking forum so that someone can assist you with this request.

Thank you,
Adam

0 Ohad Fundoianu over 5 years ago in reply to Adam Torma

Intellectual 540 points

OK, maby the clocking forum can help me too, but just for knowledge, the purpose I need the buffer for is JTAG:TMS,TCK ,TDI and Reset signals, Not for clock.

0 Adam Torma over 5 years ago in reply to Ohad Fundoianu

TI__Mastermind 45340 points

Ohad,

None of the JTAG switches at TI like the TMUX1574 or TMUX1511 devices are buffered which is I moved the thread if you want a buffer instead of a passive FET switch.

Thank you,
Adam

Clock & timing

Clock & timing forum

SN74CB3T16210: Can that device convert for sure 3.3v to 2.5v ?