I have a project in which I need to use multiple shift registers of type MM74HC595MTC (The Integrated Circuit version of the usual 74HC595).
This said, the VCC pin of my shift registers will be connected to a 5V DC source.
I will be using 6 out of the 8 output pins of each shift register (Pins QA, QB, QC, QD, QE, QF) and to each output pin, I am connecting a diode (with a forward voltage of 0.89V) along with a resistor.
For the diode to be properly biased, I need to have a current of 10 mA flowing into it.
Hence, to supply the diode with 10 mA of current, I need to know what is the output voltage value on each output pin of the shift register. This way, I would choose the suitable value for the resistor by applying the formula: R = ( (Voltage from Shift Register Output Pin - 0.89) / 0.01 )
Not normally how one would approach such a task. Designs of rail power should be "free" from the voltage transition of output gates.
Study-up on DC requirements supplying digital logic.
That's typically the voltage you supply to the register Vcc pin. At least if the output current (by output and total) is within the rated persistent limits.
I wonder what's the intended purpose of your circuit?
Search the forum for the many '595 shift register topics.
The output current per pin that I want is 10 mA (which is within the rated limit of +- 35 mA).
Since I'm using a total of 6 output Pins, each giving out 10 mA, the total current to be supplied by the shift register is 60 mA (which is also within the rated limit of +- 70 mA of the shift register).
Hence, based on your answer, the output voltage per Pin should be 5V?
As for the intended purpose of use, I have a metasurface in which each unit-cell contains a PIN diode. These PIN diodes should be turned ON and OFF according to a certain pattern, which is why I am using Arduino.
Your questions don't make sense yet. Perhaps there is a language barrier. The output currents and voltages are well specified in the data sheet. Is there something about it that you don't understand? It's great to know that you are driving a "metasurface" but without knowing its electrical characteristics (and how you have wired it), it's not possible to have a rational discussion about how to interface it to a digital logic IC.
A very short answer, the voltage on outputs is very close to the applied supply voltage Vcc, but is reduced as more current is drawn from the output pin. The current is determined by the combination of the output MOSFET driver and load circuit.
