Printed Circuit Design & Fab Online Magazine

Features

Summary statistics can be misleading, but in different ways.

C_pk and P^pk are numeric capability summaries of process or product characteristics based on common cause variation (due to chance) and assignable cause variation (special cause). Understanding these capability indices and their limitations is critical in pursuing world-class quality, "on target with minimal variation." C_pk and P_pk indices are reviewed, and details on how to use them synergistically are provided.

Two unique equations can be used when fusing a trace – each offering its own strengths and weaknesses.

Up until about 10 years ago, when PCB designers searched for information about the current needed to melt a trace on their boards, only two names popped up in the literature, W. H. (Sir William Henry) Preece and I. M. Onderdonk. Each is credited with developing a unique equation, bearing their respective name, and those equations became the basis for many PCB calculations.

Methods for assessing component temperatures and fan performance.

Cloud technology has become increasingly prevalent, allowing use of 3-D models and numerical methods to analyze CAD models of electronic devices and components. Numerical computations of conduction, convection and radiation are essential for understanding how these heat transfer mechanisms can be utilized for effective cooling techniques.

The subcontinent explodes with new EMS work, prompting a spate of IPOs.

Putting aside the obvious supply chain disruptions, the two big stories out of the EMS industry in 2022 were the emergence of India, led in particular by Apple's pivoting from China, and the number of IPOs.

While the Indian government is aggressively recruiting foreign electronics investment, there's no question India's appearance as a viable competitor to – dare we say it? – China is being driven by Apple. The world's most valuable company tripled its production to more than $7 billion of iPhones in what is now the world's most populous country during the past fiscal year,¹ mostly at the expense of China. Some reports hold Apple will raise India's share of its production to 25% in two years.

Models for predicting the effects of signal-destroying reflections.

An ideal digital interconnect is a lossless transmission line with characteristic impedance and phase delay flat over the signal bandwidth and termination resistors equal to the characteristic impedance. In such interconnect, bits generated by a transmitter would flow seamlessly into the receiver with no limits on the bit rate. Such a utopian transmission line exists only in our imagination – and in textbooks. The physics of our world prohibits that. One way to describe "what happens to the signal on the way to a receiver" is to use the balance of power that can be written for the passive interconnect as follows:

P_out = P_in - P_absorbed - P_reflected - P_leaked + P_coupled

The actual phosphorus content in the deposit must be considered.

While the current focus in the electronics industry is chips, components and microelectronics, the printed wiring board (PWB) also plays a vital role. Continued miniaturization and environmental considerations, such Restriction of Hazardous Substances Directives (RoHS), have led the industry to create and improve surface finishes to meet current and future generations of electronic assemblies. Two PWB finishes have become very common: ENIG and ENEPIG. The industry trade association, IPC, released IPC-4552 in 2002¹ to help standardize the global printed circuit board industry around a specification for ENIG. IPC-4556 was released in 2013² to establish industry standards around ENEPIG surface finishes.