Electrical Testing of Passive Components

Reading time ( words)

Introduction

Substrates have become more critical with regard to pitch and density in today’s designs with challenges for passive components in terms of surface placement. This negates the opportunity for high speed, high cost components to be placed on the surfaces of the PCB. With this the capacitance and resistive components have to be embedded into the design. This has been accomplished with the advent of buried capacitance cores and buried resistors. Unfortunately, this has caused some challenges to the ET test centers/labs in the ability to effectively test these buried passive components. Processes have had to change and adapt to these new technologies. The paper will discuss what these new technologies are and how the electrical test arena has adapted to provide accurate testing of the buried resistors and accommodate the buried capacitive cores to not receive false errors from the grid testers and flying probes.

Resistors

In the past, pull-up, terminating and voltage dividing resistors have been placed on the surface of the PCB. Early applications were standard carbon resistors placed on the board utilizing plated through-holes.

As can be seen in Figure 1, the standard carbon resistor took up a lot of space on the PCB. You will also notice in the photo that capacitors are also stealing valuable space from the surface topography. As time progressed, SMT technology was introduced and the older, bulky standard carbon resistor was replaced by the newer SMT packages (Figure 2).

This was a very popular innovation to the industry as now the surface footprint was drastically reduced and the topography on the surface of the PCB was now open to accommodate more active components which reduced the overall size of the PCB, but also allowed the complexity of the designs to grow. No longer was a PTH as needed for the resistor, which allowed the multilayer to expand its capabilities on the inner layers to provide not only an overall smaller PCB, but a more powerful final product.

Read the full article here.


Editor's Note: This article originally appeared in the July 2014 issue of The PCB Magazine.

04/28/2020 | I-Connect007 Research Team

I-Connect007 continues to monitor the current worldwide economic situation by seeking input from our market leaders. Here’s what we discovered: If you’re feeling the pressure, you’re not alone. In a recent survey, we asked about your primary concerns for the future of our industry. The number one concern (26%) indicated a belief that sales will be affected negatively in the coming months.

04/15/2020 | Barry Matties, I-Connect007

On April 14, IPC president and CEO, Dr. John Mitchell, described IPC’s ongoing efforts related to COVID-19 with I-Connect007 Publisher Barry Matties. From a standpoint approximately 30 days into the U.S. shutdown, Mitchell reported that 94% of the executives attending the executive forum are expressing concern. He also outlined many of the chaotic drivers and influences in the industry, including shifting over to different, mandated products; supply shortages; potential declining demand for normal products; and increased shipping costs. Worker and staffing shortages have also become an emerging concern.

03/30/2020 | Nolan Johnson, PCB007

Todd Kolmodin, VP of quality for Gardien Services USA, updates Nolan Johnson on Gardien’s operations. Specifics include Gardien’s certification as an essential business for U.S. Department of Defense work and an overview of the work and staffing policies in place at all of the company's facilities across the United States and the various work restrictions—all with the goal of “keeping the wheels turning” in the industry.