Tom
10-14-2002, 03:51 PM
IPC Advanced Study Guide Page Reference: Page 260, Section 4.12
The term "signal integrity" pertains to all the characteristics that must be considered in the design and manufacture of a printed board intended to truly perform as an integral part of the circuit. Terminology used to describe different types of boards include in the general terms printed wiring board and printed circuit board. Printed wiring boards were initially intended to replace wires used in interconnecting electronic components; printed circuitry truly becomes a part of the circuit and therefore must perform functions that are consistent with the circuit performance characteristics.
Items that should concern the designer in evaluating the signal integrity of his printed circuit board includes such items as:
- Impedance control
- Capacitance characteristics
- Inductance considerations
- Crosstalk
- Critical signal speed
- Signal propagation delay
- Switching noise
- And all of the manufacturing elements that impact those characteristics
The ability of a fabricator to successfully achieve the desired conditions of the circuit repeatedly is directly related to how narrow the tolerance window can be held on critical dimensions. The design specifications, coupled with the process tolerance window, play a major role in determining process capability. Consideration of process variations as the specification tolerances are being established early in the design stage, can greatly benefit the manufacturability of the printed circuit board and thus allow some guarantee of the signal integrity as defined by the design principles.
The term "signal integrity" pertains to all the characteristics that must be considered in the design and manufacture of a printed board intended to truly perform as an integral part of the circuit. Terminology used to describe different types of boards include in the general terms printed wiring board and printed circuit board. Printed wiring boards were initially intended to replace wires used in interconnecting electronic components; printed circuitry truly becomes a part of the circuit and therefore must perform functions that are consistent with the circuit performance characteristics.
Items that should concern the designer in evaluating the signal integrity of his printed circuit board includes such items as:
- Impedance control
- Capacitance characteristics
- Inductance considerations
- Crosstalk
- Critical signal speed
- Signal propagation delay
- Switching noise
- And all of the manufacturing elements that impact those characteristics
The ability of a fabricator to successfully achieve the desired conditions of the circuit repeatedly is directly related to how narrow the tolerance window can be held on critical dimensions. The design specifications, coupled with the process tolerance window, play a major role in determining process capability. Consideration of process variations as the specification tolerances are being established early in the design stage, can greatly benefit the manufacturability of the printed circuit board and thus allow some guarantee of the signal integrity as defined by the design principles.