I am trying to use a 74LVC245A from gpio pins on a beaglebone black to drive LEDs on 5V circuits. When I first put it together, I have VCC tied to 5V (the voltage i want to convert to). A->B is tied high. OE is tied low. This all works as is. But I might be using it out of spec. The datasheet has two tables of info that seem to conflict. The “Absolute Maximum Ratings” says VCC can be from -0.5V to 6.5V. The “Recommended Operating Conditions” table says 1.65 <= VCC <= 3.6V. At the top of the datasheet it also says “Operates From 1.65 V to 3.6 V”. I am confused. Is it OK to have VCC at 5V, A[n] controlled by 3.3V on beaglebone and B[n] sinking 5V LED circuits?
The supply is intended to be <3.6v. It will tolerate 5v TTL signals at it’s inputs and outputs. I’m not sure if that includes sinking current from a 5v LED but my thinking is you should be OK. You do need to be aware that each output can sink up to 24 mA and all outputs (simultaneously) only a total of 100 mA max.