Characteristic
Impedance
of Microstrip:60-70 Ohms for w/h =
1,
and 40-50 ohms for w/h = 2. |
Average
Propagation Delay:
2
nS / ft This is an average between microstrip and
stripline. |

Characteristic
Impedance
of Stripline: 0.6 times that of
microstrip. |
Typical
Propagation Delay:
150
pS / in for Microstrip, or 180 pS / in for Stripline. |

.Characteristic
Impedance
of Asymmetric Stripline: 0.75 times
that of microstrip |
FR-4 Epoxy Glass
Dielectric
Constant:Between 4.0 and 5.0 according to
the
composition, typically 4.5. |

For < 2%
Crosstalk:s
= 4 h for Microstrip, and s = 2h for Stripline. |
.For Other
Dielectric Materials:
Characteristic
impedance is proportional to one over the square root of the dielectric
constant. Propagation delay is proportional to the square root of
the dielectric constant |

Maximum
Unterminated Stub
Length:L(in) = tr (nS) |
Dielectric
Constant of Other
Materials:FR-4
= 4.5, PTFE = 3.2, Polyester = 3.2. |

**Note: w = width of trace, h = height of trace above
the
reference plane, s = spacing between traces, tr = rise time.**

**© 2000 Henry W. Ott**

Henry Ott Consultants 48 Baker Road Livingston, NJ 07039 Phone: 973-992-1793, FAX: 973-533-1442

February 14, 2001