Other Parts Discussed in Thread: LSF0108, , SN74AHC1G126, SN74LVC2G126, SN74AUP2G125
Tool/software:
So i need change the voltage LVL of a TDM 4mHz buss from 1v8 to 3v3. TDM master also changes ( it is either on the 1v8 side or the 3v3 side, i can obtain a signal from the 1v8 side that tells if it is or not the master).
Due to certain reasons like buss capacitance and IC drive strength i need to buffer the FS and CLK signals [LSF0108 alone is not an option].
I know of 3 potential solutions:
1 with SN74AXC8T245
Can i connect 2 middle signals of the SN74AXC8T245 so that it buffers in both ways [signals A3/4 to A5/6 AND B3/4 to B5/6 ] using the DIR2 pin and the signal i mentioned previously ?
My concern regarding this solution is latching , the SN74AXC8T245 has way higher drive strength then the ICs on both the v8 and 3v3 sides. I am afraid that the SN74AXC8T245 will get stuck in some sort of self oscillating state or even stuck in a random high or low state.
Is there any knowledge regarding such configurations ? Is the PSPICE model provided accurate enough to test such behavior?
2 with LSF0108 and some SN74AHC1G126
This solution would use the LSF0108 to voltage shift and then on the 3v3 side i intend to use 2 back to back SN74AHC1G126 as buffers , the enable pins will be controlled like this: one by the control signal mentioned before and the other one with the same signal but through a NOT gate.
The problem with this solution is that it uses 4 ICs and i don't have a model for the LSF0108 so i cant even simulate it.
2 some SN74AHC1G126 or better
This option is very similar the the previous one but now i remove the LSF0108 and simply use the SN74AHC1G126 as a LVL shifter ( same logic as before) the problem here is that the min supply voltage is 2V in the case of SN74AHC1G126 and that is a but close to the max voltage on 1V8 logic. There probably is something similar that accepts lower supply voltage as input....
Maybe the SN74AUP2G125 or SN74LVC2G126 ?
This solution seems more practical but i still think there is a more integrated solution...
4 something else recommended by TI
