View Full Version : Propeller 3.3V to 5V input

11-18-2010, 06:24 AM
I have to interface an propeller output to an SN75451 input that is operating at 5V, can i simply connect a pull-up resistor like this ?


11-18-2010, 06:32 AM
The SN75451 has TTL compatible inputs. That means that they recognize a HIGH with as little as 2.4 V, the propeller outputs some ~3.3V without load (and 3.2V with a TTL load '245). Without a pull-up it should work well. (But I'd add a small 200 to 300 ohm series resistor, just in case).