I tend to be very paranoid when it comes to making PCB's to the point where I try to use 50+ mil tracks for ground wires when routing the board. After, I fill the remaining space on the board with a ground plane.
I have come across a situation where I tried routing with fewer wire jumpers and even though routing is 100% successful, the ground pin from a DIP IC leading to some components consists of a 20mil wide track with a length between 5mm and 1cm before the track turns into a large ground plane (at least 200mil wide).
Since wires have resistance, I just want to make sure that such traces leading to ground planes are acceptable. If I could, I'd connect the DIP IC ground to a middle of a > 200mil wide ground plane.
So will my circuit be negatively affected by resistance/inductance if the ground of a DIP IC is connected to a large > 200mil ground plane through a 20mil track of 1cm length?
If no, then what's the maximum length I can use at 20 mils before noticing any bad effects?
My circuit will be done on a single-sided FR4 PCB with 1oz copper thickness, and My other PCB tracks and spacings are minimum 10.5 mils.
The power going through the circuit is 5VDC and the speed of operation is no more than 24Mhz.
I will add that the IC's used in my circuit are the 74HC types and cmos types.
Best Answer
For 2OZ copper, 1cm of 20mil track is about 5mOhm. Assuming your mcu sinks a max current of 100ma, you'll get a vdrop of about 500uV. This is pretty tiny. The inductance will likely not be a big deal either. With microcontrollers, the most important thing is how quick the current draw changes. You can mitigate this by putting a small decoupling cap as close to the IC supply pins as possible. This is what inductance affects, so you want to make the loop as small as possible (i.e. the length is more important than the width).