Hey guys,
So i'm using the 4051 IC as a demux to drive a 7-segment LCD with an Arduino. I know I have to use three i/o pins as the s1,s2,and s3 inputs, but I'm not sure what to do with the 'z' pin. Can I just leave it at 5V so that whatever pin I write to is at 5v?
Thanks,
alex
So i'm using the 4051 IC as a demux to drive a 7-segment LCD with an Arduino.
Why that is totally the wrong chip to use. It is an analogue multiplexer not a digital multiplexer, it is not even latched so is quite useless for what you want.
What IC would you use then?
[EDIT] After some snooping around. I discovered the 74138 digital demultiplexer (doh!) Since I already bought the 4051's, is there any advantage to using the 74138 over the 4051?
About the latch, correct me if I'm wrong, but since I'm demultiplexing at a rate of 100/7 ~ 143Hz, do I really need a latch?
Much appreciated,
alex
4511? 7007? TLC5940? an atmega8 configured as an i2c slave?
is there any advantage to using the 74138
Yes it has digital outputs. That means it supplies the current and the current is not being pushed through an analogue switch. The 4051 can have an on resistance of up to 130R according to the data sheet. If you start pushing current through that it will get warm, you will have to do the sums to see if it breaks it.
Also that is the maximum series resistance so different paths through the device could have different resistances, that would mean the brightness of any segments would change depending on the path through the device.