CD74HC4050: Not getting any output

Michael Burris

Part Number: CD74HC4050

Tool/software:

I am trying to use the 4050 chip and am not getting anywhere. I am using 3.3v as VCC and the input is 12v in hopes of getting 3.3v on the output. I am using 1k pulldown resistors on each input and 10k resistors on the output to the uP . I tried bypassing the input resistor and appeared to draw over an amp but still nothing higher than 0.48v on the output. Schematic is here: www.dropbox.com/.../CD74HC4050PWR-circuit.png

TIA

4 months ago

0 Clemens Ladisch 4 months ago

Guru 316940 points

What exactly do you mean with "bypassing the input resistor"? Are you shorting the inputs to ground?

If the inputs themselves draw current, then you do not have a CD74HC4050, or the device got damaged.

0 Michael Burris 4 months ago in reply to Clemens Ladisch

Prodigy 10 points

Thanks for the response. In my schematic, I have 1K resistors on the inputs to pull the input down and keep it from floating. I bypassed the 1K resistor and that seemed to draw the 1 amp current. Whether or not I use bypass the 1K input resistor and the 10k output resistor, I a still not getting any output voltage over 0.48v.

The writing on the top of chip:

HJ4050
TI 47K
CECL
9M

+1 Clemens Ladisch 4 months ago in reply to Michael Burris

Guru 316940 points

What is the voltage that you measure at the input pin?

0 Michael Burris 4 months ago in reply to Clemens Ladisch

Prodigy 10 points

12v on the input pin and 3.298v on VCC

0 Clemens Ladisch 4 months ago in reply to Michael Burris

Guru 316940 points

Is there any load on the output? The voltage should be 0 V or 3.3 V, unless some current flows somewhere.

0 Michael Burris 4 months ago in reply to Clemens Ladisch

Prodigy 10 points

no load, just the meter

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CD74HC4050: Not getting any output