I'm trying to route 10 DIP ICs on a single-sided PCB, but because of my available pcb space, I cannot fit all 10 ICs in one single row. Instead, I lined them up in three rows.
It seems that if I connect the VCC pin on every IC to the positive through some sort of jumper wire instead of a direct connection on the PCB itself then the odds of me being able to route the whole board to 100% rise significantly. Same deal with GND pins.
If I'm not mistaken, adding jumper wires introduces either inductance or resistance and too much of that can create undesirable results. The ICs I used are of mixed types: some digital like the 74HC, an op-amp, sound chip (ISD1700), DAC, etc.
I was initially thinking connecting jumper wires from +ve of battery to VCC and using maybe a couple 0 ohm resistors in parallel to minimize bad effects, but I'm not sure. The point is, I want to be able to route the whole circuit to 100%.
Which is better:
Connecting the VCC pin of every chip (or at least the digital IC's) to the +ve of the battery through a jumper wire and connecting ground directly to the -ve of the battery?
OR
Connecting the ground pin of every chip (or at least the digital IC's) to the -ve of the battery through a jumper wire and connecting VCC directly to the +ve of the battery?
and why?
Best Answer
Generally speaking, you want the best signal integrity on your ground network, because signals as well as power are referenced to it.
That said, it is not necessarily true that a narrow trace on a single-sided PCB is better than a wire jumper or zero-ohm resistor in terms of its impedance. A 1-mm trace on "1 oz." (35 µm) copper is roughly equivalent to AWG30 wire, whereas soldered jumpers are typically AWG22, which has 1/6 the resistance.
Of much greater significance is how well you bypass or decouple the power on each chip. You want to use the most direct path possible between the capacitor(s) and the power/ground pins of the chip.