I have a simple circuit with a simple problem that I just can not fix.

I have a 74HC4050D hooked up to an SD card. I have a 0.1uf on the 5V line and 2.2uf on the 3.3V line. Whenever a signal is sent on the 5V line the Vcc on the 4050 will drop down to 0.8V and then rise back up after the signal stops. The 3.3V out of the regulator is rock steady, only the 4050 and SD card are connected to this supply. This happens when the card is removed as well.

I have tried putting a 100nf cap directly across the 4050 but it still drops to 0.8V.

Any idea how to solve this?

  • 1
    \$\begingroup\$ Can you provide a diagram, including the pin numbers on the 4050 (it does not have to be fancy - although you can use Ctrl+M)? I have recently used a CD4050 to interface a 5 V microcontroller to a 3.3 V device, and I did not encounter any problems. \$\endgroup\$ – Peter Mortensen Aug 11 '13 at 0:41
  • \$\begingroup\$ Att. [filler filler] \$\endgroup\$ – Peter Mortensen Aug 16 '13 at 22:57

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