Hi team,
Hi team,
I notice that the VIL and VIH requirement in TXS0108 is VCCI-0.2 and 0.15.
And the output of the TXS0108 is about 0.65*VCC.
So it seems the common TTL and COMS level can't meet the requirement.
So can the TXS0108 use in the common TTL and CMOS application?
If not, what's the normal application of the TXS0108?
And if there is other part can be used in the translator in CMOS and TTL?
Lacey
Thanks a lot!
TXS devices are primarily designed to be used with bidirectional open-drain signals (such as I²C), although they also work with push/pull signals. In any case, it does not make much sense to use them with unidirectional signals.
For DC operation, the accelerators do not matter; the pass-gate transistor is either on or off:
When Npass is on, it behaves like a resistor (it has about 300 Ω to 500 Ω). For a logic-low signal, the TXS is a passive device; if you want to sink current at an output pin, that current must be sunk by the device that drives the corresponding input pin.
So the VIL does not specify a voltage level at which internal logic switches, it is just a voltage that is low enough so that the specified VOL is reached at the specified current (IOL) flowing through the device. If your circuit uses a smaller current, the voltage drop will be lower, and you can use a higher VIL and still reach the same VOL. And in practice, when you're not using any external pull-up resistors, the current will be at most 250 µA, so your external device will be able to drive the input to a level much lower than 0.15 V.
