CD4514B: Connecting capacitive load on both side of the DEMUX output

Hi David,

Q1. Does the decoder input (Data 1,2,3,4) voltage level has to be similar to VDD?

For instance, I wish to connect VDD = 15V and the decoder inputs to the MSP430's 3.3V GPIO pins to control the output.

Or do I have to connect 15V to the decoder inputs?

If you look at the electrical characteristics section of the datasheet at the spec of VIH for VDD = 15V, you will notice that it says 11V. So you will require atleast 11 V at the input for the output to go high.

Q2. What does the strobe pin do?

Strobe latches the data presented at the input. So when strobe is high, data can be read into the latch. When strobe goes low, the data is latched at the input.

Q3. Just like this picture, I was looking for a data input Din pin.

However, I cannot find it from the CD4514BM96. Is there a data pin?

This device is a decoder not a demux. There is no data pin. You can connect your data to the inhibit pin and use that to transmit data to the outputs.

Q4. If I connect the load's terminal to output 1 and 2 to control the load current's polarity, will this damage the DEMUX?

Connecting the outputs together through a load is no problem as long as the outputs are able to meet the sink and source current requirements listed in the datasheet. Look at the IOH and IOL specs in the electrical characteristics table in the datasheet. The output current should not be greater than this amount of current and there will not be a problem. You will need to increase your resistor size to avoid high current flow from one output to another.

Thanks!

-Karan