Problem with 74HC4067 multiplexer

hi, let us discuss ..........................................................................................

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Hi, good afternoon, I am an Electronics Engineer, I have worked with the CD74HC4067 CMOS multiplexer in the past, I think that that the problem could be caused by phantom addresses. How are you driving the IC addresses (pins S1-S4)? Please, message me so we can talk about this. Regards,

Hello, can you share the schematic for better understand where is the problem? Thanks

hi.... There seems to be a problem with your firmware. Are you choosing s0,s1,s2,s3 correctly? If they're all correct, let's look at your sketch and discuss it.* Are there any problems with the board? A/D conversion time?...send me message!!! Thanks and regard.

So instead of bidding on your project, i will just give you some suggestions for things to look for. Some are very obvious and simple while others might be a little more non-obvious. 1. First, is this problem limited to only ONE part or are several affected? In other words, the part may be defective. 2. Check the VCC line to see that you aren't applying too much voltage (this particular HC part is rated for 10V max). 3. Make sure that the Analog Inputs =never= exceed the VCC supply voltage. If they do, the analog signals can possibly "bleed" into other input channels causing something like what you describe. 4. Make sure that the VCC and GND wiring is a very SOLID low impedance path (not, for example, tiny little wires). 5. Check that the VCC and GND lines are quiet and noise free and that there is a 0.1uF decoupling capacitor near to the part. This is more important in TTL Logic circuits but is still helpful to eliminate stray noise even in CMOS logic circuits. 6. Verify that the channel select control lines are clean and that none of them are "floating" and make very certain that none of the select lines are shorted to each other. That would also cause some of the things you described (the problem may then also be in the circuit that is driving those lines). 7. Verify that the Enable pin is solidly grounded when the part is in operation.

Hello i have been working with HC Chips for many years i have got that Multiplexer i have got older Version CD4067 and that is the same i can prove you with both datasheets it is the same the CD4067 has working voltages from 3V to 18V and HCMOS version only works from 3V to 6V i can help you fixing your problem i just need the application schematic from you. have a chat with me i i will show you