 # SI / PI Calculator V2.6

Over the past 20+ years I've spent my professional career doing high speed Signal Integrity (SI) and Power Integrity (PI) analysis. I am a big fan of Eric Bogatin, in particular his "rules of thumb" for SI analysis. In the PI domain, I've also been appreciative of the works and publishings of Douglas Brooks. From these two, and many others, I have gathered some various calculations into an "SI/PI Calculator" for use on PCs. This program is freeware.  This calculator contains a number of "rule of thumb" calculations useful in initial Signal Integrity and Power Integrity analysis and design. As is strongly preached in the SI/PI world, full simulation is strongly recommended for a true analysis of a design. However, for early design stages, for answering a quick "swag" question, or for impressing your peers with a quick response, this calculator can give you a ballpark answer.

Note: this was developed using Visual Studio 2015 and is therefore PC based. To run on a Mac you'll likely need some form of Windows emulator.

## User's Manual What is included:
• SI Calculations:
• Impedance Calculations for Single Ended and Differential Microstrip and Striplines
• Skin Depth calculations
• What is the skin depth in annealed copper at any given frequency?
• For any given trace geometry, at what frequency does the skin depth dominate the trace impedance?
• For any given trace geometry, what is the DC impedance and effective impedance at any given frequency?
• Fiber Weave Skew calculations
• At any give baud rate, or edge rate, what is the maximum recommended trace segment length that should be routed parallel to the X or Y axis to avoid Fiber Weave Skew effects?
• Differential P/N skew calculations
• For any given baud rate or edge rate, what is the maximum recommended routing skew allowed between the P and N nets of a differential pair?
• Via Stub calculations
• For any given geometry of a differential pair of vias, what is the expected null frequency (in the insertion loss) created by the via stubs?
• For the same geometry, what is the approximate -3dB frequency (in the insertion loss)?
• For the same geometry, what is the recommended maximum allowed via stub length?
• DC Blocking Capacitor calculations
• For any given differential channel and protocol, what is the minimum recommended DC blocking capacitor value that should be used?
• For this channel and capacitor, how long will it take for the signal to converge?
• Differential Via impedance calculations
• For any given differential via geometry, what is its differential impedance?
• "H", "T", and "Pi" attenuator calculations
• What resistor values should be used to generate XdB of insertion loss in a channel while maintaining the desired Z0?
• PI Calculations:
• Trace Temperature calculations
• For any two of these three....
• Trace geometry (minimum)
• Trace current (maximum)
• Trace temperature rise (maximum)
• ... calculate the third
• Fusing Current calculations
• For any two of these three....
• Trace geometry
• Fusing current
• Fusing time
• ... calculate the third
• Also calculates the difference between fusing of a wire in open space vs. a trace on a PCB.
• Trace to Wire gauge calculations
• Estimates effective wire gauge based on trace geometry, or
• Calculate trace geometries needed to equate to a specified wire gauge
• Plate Capacitance calculations
• Parallel plate capacitance is often used as part of a decoupling circuit for PCB design. This calculates the effective capacitance for any given parallel plate geometry.
• Decoupling Capacitor Resonance and Effective Impedance calculations
• For common ceramic capacitors used in a decoupling circuit, this shows the nominal resonance and Zeff based on best current practices for mounting structures.
• AC Target Impedance calculations
• Calculates the AC target impedance for a power distribution network (PDN) based on the voltage, allowed ripple, and peak transient current of the PDN.
• Via DC Impedance and Current Capacity
• For any given via geometry, what is its resistance, current carrying capacity, voltage drop (at a given current) and thermal resistance
• DC Current calculator
• In the absence of any information from a device manufacturer, this can be used to calculate the DC and transient current draw from the power supply for the device, based on its I/O specifications and application.

• Note: The "Help" menu is tab-aware and provides general information on which ever calculator is currently selected.  ## Release Notes:

• V2.4 - Initial public release
• V2.5 - Added Via Impedance and Current Capacity
• V2.6 - Added DC Current calculator Back to my Shareware Home Page