how many output voltage 74hc595 ?

if the five voltage input to vcc 74hc595. i looking at it on the datasheet page 5 of 13. i looking at DC SPECIFICATIONS "V OH"

High Level Output Voltage (for QA to QH outputs) approximate voltage 4.5.

how many the QA to QH able output mA? i could not find the excalty output each mA.

I am trying to figure it out by using 8x8x8 matrix.

p.s. data sheet link is http://pdf1.alldatasheet.net/datasheet-pdf/view/23119/STMICROELECTRONICS/M74HC595B1R.html

The link to the data sheet doesn't work for me.

However, I think you are confusing voltage and current. The maximum output on pins QA-QH is ± 35 mA, but the total amount of current per device is ± 70 mA. So you will either need a transistor on each pin or consider using TPIC6B595N.

With a 5V supply, the 74HC595 can output 4mA and maintain ~4.5-4.8V output. More current than that and the voltage will start dropping. The whole part is only rated for 70mA max current flow. A better solution is to use a high current sink shift register such as TPIC6B595 to sink current from the layers, and switch P-channel MOSFETs to provide current to each layer.

i am starting consider using TPIC6B595N intead of using transistor it would be too much work on the PCH. TPIC6B595Ns are cheaper than transistors and 74HC595. maybe save five dollars not bad. i did not realized that. thank you so much to dannable and crossroads!

dannable: However, I think you are confusing voltage and current. The maximum output on pins QA-QH is ± 35 mA, but the total amount of current per device is ± 70 mA. So you will either need a transistor on each pin or consider using TPIC6B595N.

Can the TPIC6B595N ouput 5V with high current? I read the datasheet and it seemed like it could only sink it (even the pins are called "DRAINx".

TPIC6B595 only sinks current. Use a resistor from 5V to supply current.
Here’s an example where the LEDs are wired up as if they were 8 LEDs in a common anode package.

forget to add...

the layer using the P CHANNEL IRF9Z24N output. once the TPIC6B595N received the sink current at row the current will go into DRAINx called N channel.

I am wondering if the P CHANNEL output with high current on 8x8x8 each layer. the led is 20mA forward voltage so 8x8 = 64 then 64 time 20mA = 1280 mA? will it effect voltage reduce? what is the best use voltage output using the P CHANNEL?

so far i know is green and blue is range 3.5 voltage for 20 mA.

CrossRoads: TPIC6B595 only sinks current. Use a resistor from 5V to supply current. Here's an example where the LEDs are wired up as if they were 8 LEDs in a common anode package.

that what i thought

5V is good for the P-channel to connect to the anodes. You do indeed need a good power supply, 5V@ 2A would be good. I have used this one in several projects too. Little overkill, so it will run cool, and a good price. http://www.mpja.com/5-Volt-DC-Plug-Power-Supply-4A-Regulated/productinfo/18520%20PS/

roger that. :slight_smile: