Spring Loaded Contact Probes and its Types

Spring loaded contact probes also known as pogo style pin have delivered excellent mechanical and electrical performance. The price of these probes is relatively high because each pin is constructed of 3-4 discreet parts manufactured and assembled in a laborious, less than fully automated process. The costs could be exorbitant so lower performance alternatives are required to reduce costs.

There are many ways of designing pogo pins and one is the traditional way of designing pogo style pins. This design is the most favored way as it uses a typically constructed pin, two plungers and a spring encapsulated in a metal shell. This style is highly compliant which means it is designed to compress or comply during insertion. This particular style is critical when attempting to maintain a good connection despite potentially uneven surfaces, varying heights, errors in parallelism and flatness, or pivoting or rotating elements.

The trend towards more compact, high electronics density design – defines as the number of pins in a small area or the distance between pin centers is already impacting several markets.

Design as the H-Pin:

The H-Pin is a stamped spring probe that delivers the mechanical, electrical and thermal performance of a pogo-style spring probe. The highly compliant pin has a working range up to 1mm with a flat spring rate and can be utilized up to 15 GHz and can carry up to 4 amps of current and withstand temperatures up to 200 degree Celsius.

Depending upon the quantities the spring-loaded probe pins can cost 30-35 percent less. With thousands of pins potentially in a single test socket or board to board connector, the savings can be significant. 

Meeting the High-Performance Demands: 

For spring loaded probes pins high-performance characteristics are defined by the ability to withstand high temperatures required for burn-in and other tests, ability to handle increasing amounts of current over increasingly smaller pins, and the ability to handle high frequencies. Moreover, the H-Pin works well when exposed to the high temperature above 2000C. The tests are typically conducted with temperature ranging 2200C to 2400C and despite cooling the back side, the spring pins still experiences a fair amount of temperature. These all come in a package of semiconductor and have power management features that need to be tested as well. For high-performance applications, there can be concerns about the construction of traditional spring-loaded probe pins and how its designs can affect the quality of the connection under compression. The performance of the pin as measured by its contact resistance is also a benefit in high-frequency testing.