Dec 07, 2011 · I’ve gone through the datasheet and one thing I’ve noticed is that ULN2803 has 8 input and 8 output pins, and 74164 is a 8 bit serial to parallel convertor. So I thing you are trying to make a 8*8 led matrix display. Connect 8 output pins of the controller to 8 inputs of ULN2803.

DM7408 Absolute Maximum Ratings(Note 1) Note 1: The “Absolute Maximum Ratings” are those values beyond which the safety of the device cannot be guaranteed. The device should not be operated at these limits. ULN2003 datasheet, ULN2003 pdf, ULN2003 data sheet, datasheet, data sheet, pdf