cd4051 bug?

whoandcar · 25th December 2004, 07:11 PM

I made a project using a cd4051 to select one of 5 inputs and take the output from pin 3.
Some times it seems that the signal on input #3 crosses to input #4. I mean that with no input at all at pin 4 there is still signal at the output (with input# 4 selected) Taking out input #3 the output disappears.
I made abou a hundred devices, and there are about 15-20 of them faulty. The strange thing is that only input 3 crosses to input 4. Al others work as intended. Is there a bug in the 4051? Someone heard of somethiong like this before?
I am using +5 Volts on Vcc, addresses come from a PIC 16F84 and Vee is minus 7,5 Volts. analog signals are in the 6 - 8 V p-p
Thank you!

25th December 2004, 07:11 PM	#1
whoandcar diyAudio Member Join Date: Sep 2004 Location: mendoza	cd4051 bug? I made a project using a cd4051 to select one of 5 inputs and take the output from pin 3. Some times it seems that the signal on input #3 crosses to input #4. I mean that with no input at all at pin 4 there is still signal at the output (with input# 4 selected) Taking out input #3 the output disappears. I made abou a hundred devices, and there are about 15-20 of them faulty. The strange thing is that only input 3 crosses to input 4. Al others work as intended. Is there a bug in the 4051? Someone heard of somethiong like this before? I am using +5 Volts on Vcc, addresses come from a PIC 16F84 and Vee is minus 7,5 Volts. analog signals are in the 6 - 8 V p-p Thank you!

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