Hello,
For our test design, we need to convert varying voltage logic from our DUT (5V to 2.5V) to 3.3V TTL pic microcontroller.
Our DUT cannot drive the two TXS in series that does this conversion.
So we plan to use a driver like : SN74LS07. This will definitely sink enough current. Do you see any issues using this buffer to drive the TXS? I don't need any external pull-ups correct?
Thanks
Sanjeevi
Hi Sanjeevi,
I assume that this is unidirectional translation.
The DUT can be connected to a logic buffer which is over voltage tolerant like the SN74LV1T34 as shown below.
You do not need the 2 TXS in series in my opinion. Also, the fact that the TXS voltage supply has restrictions on the supply biasing. It requires Vcca<Vccb and with varying voltage like your case, it is not possible.
Thank you for the suggestion Shreyas. Yes this does seem simpler than what i had previously. Just to confirm, So this buffer, when connected with a Vcc of 3.3V will convert any voltage in the range 1.8V to 5V into 3.3V?
Just out of curiosity, I was aware that TXS needed Vcca<Vccb. So when I used two TXS in series, this is how I connected (see image). Will this have worked, assuming my DUT can drive the TXS, which it can't hence going for the buffer solution...
