I have a circuit requirement using a Texas Instrument CD40109BE Voltage Level Shifter. This chip incorporates 4 low to high level shifting circuits. I plan to use two of these circuits, A and B with C and D disabled.

The input voltage for both channels is 5 V TTL level and the output is 12 VDC, from two independent power supplies. In addition, I will be switching the input level at a frequency between 500 Hz to 2 kHz with a square wave from a Pulse Width Modulation source of variable duty cycle. The 12 VDC output to follow the 5 V TTL input waveform.

I'm not an expert in electronic component design and was wondering if someone can provide a detailed circuit connection diagram for such a circuit.

  • 1
    \$\begingroup\$ Please link a datasheet. Also there must be a typical application schematic in it to start with. \$\endgroup\$ – Bence Kaulics May 26 '16 at 6:48

Here you go.


simulate this circuit – Schematic created using CircuitLab

  • \$\begingroup\$ Thank you for your prompt replies Peter, Bence and @Steve for the sketch. I have one additional question on the circuit you provided. Is Vss (Pin 8) connected to the 0V of the 5 VDC power supply or 0V of the 12 VDC power supply? As an alternative, if isolation isn't required, what is your opinion on connecting the 0 VDC of both power supplies together on Vss (Pin 8) and and possibly grounding? Thank you once again and please excuse any errors as it is my first experience using this engineering service. Ted \$\endgroup\$ – Ted May 26 '16 at 20:27
  • \$\begingroup\$ @Ted Connect the 0V of both supplies together, this then connects to pin 8. BTW although this is called "ground" there is no need to connect it to ground or earth. \$\endgroup\$ – Steve G May 26 '16 at 20:37
  • \$\begingroup\$ Thank you for your reply @Steve. This is what I had anticipated but needed confirmation. This is running an industrial application with a variable pulse width being generated from an Omron PLC driving a linear motor. I guess earth grounding will be dependent on electrical noise once I scope it with the motor connected but usually it isn't required otherwise. Thanks again for your help... \$\endgroup\$ – Ted May 26 '16 at 20:59
  • \$\begingroup\$ An update. Connected the circuit as shown above using two channels only and it functioned as intended. Should anybody else be using this circuit, please note a small typo in the above sketch.... pin 13 on the left should read pin 15. Thanks again. \$\endgroup\$ – Ted Jun 9 '16 at 22:44
  • \$\begingroup\$ @Ted corrected DEN to pin 15. \$\endgroup\$ – Steve G Jun 10 '16 at 11:33

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.