Drive LED Matrix with 74HC595 to MIC2981 and TPIC6A595

Other Hardware LEDs and Multiplexing
1

I am driving a 10x11 LED matrix with Arduino UNO and using these components:

Source – 74HC595 to MIC2981
Sink – TPIC6A595

Schematic attached.

I want to shift data to both 74HC595 and TPIC6A595.

Question 1 - Can I cascade these different type of shift registers together? If so, do they connect like this:

74HC595 TPIC6A595 2nd TPIC6A595
Pin 11 SCK Pin 10 SRCK Pin 10 SRCK
Pin 12 RCK Pin 9 RCK Pin 9 RCK
Pin 9 QH* Pin 22 SER_IN
Pin 15 SER_OUT Pin 22 SER_IN

Question 2: Where does TPIC6A595 LGND connect?
The Data Sheet has a statement that says “A single-point connection between LGND and PGND must be made externally in a manner that reduces crosstalk between the logic and load circuits."

Question 3 – Does TPIC6A595 ~G simply connect to GND?

Question 4 - Is it ok to leave TPIC6A595 pins 11 – 15 unconnected?

Thank you for your help and knowledge.

Schematic.jpg
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2

Schematic.jpg
Schematic.jpg2500×2599 710 KB

A1: correct.
A2: ground.
A3: yes. Or to an Arduino pwm output if you want to dim the whole matrix.
A4: yes

3

Thank you PaulRB. Am I using the two shift registers and MIC2981 properly as source and sink?

4

I've never actually used mic2981, but as far as I can see, yes.

The "A" variant of tpic6*595 is overkill. But if it was the cheapest/only available, fine.

There is also mic5891. I've never used those either, but they combine a shift register with a high current source driver in a single chip.

5

Thanks PaulRB. I will look into MIC5891!