Circuit Negma

C++, C, VB.NET, PCB, Electronics, Circuit Design

PCB Design Guidelines

Posted by Circuit Negma on May 8, 2008

Electrical Design Factors

Conductor Capacitance

C = 0.31 a/b + 0.23(1 + k) log10 (1 + 2b/d +2b + b2/d2)

k = Substrate dielectric constant
a = Conductor thickness
b = Width of conductor in inches
d = Distance between conductors in inches

Conductor Resistance

R = 0.000227W

W = Width of conductor

Characteristic Impedance

Zo = R + jwL / G + kwC

Zo = Apparent Z of an infinitely long line in ohms
R = Resistance in ohms
L = Inductance in Henries
G = Conductor per unit length of line in mhos
C = Capacitance in farads

Characteristic Impedance for a Micro Strip

Zo = (h/W) (377 / (Sqrt. er) {1 + (2h/PI W)[1 + ln(PI W/h)]}

h = Dielectric thickness
W = Micro Strip width
er = Effective dielectric constant of substrate


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: