![]() ![]() The resolution to the problem is to make the pogo pin as short as possible. For arrays, however, pogo pin approaches cannot achieve a 50-Ω contact in area array devices, because it is virtually impossible to make a pin that would have a characteristic impedance of 50 W and fit into the tight pitches currently used.įor area array devices such as BGA, QFN or LGA, it is impossible to fabricate 50-Ω coaxial contacts at the necessary pitches of 0.4 to 0.65 mm. Pogo pins have been considered the best compromise for suitable electrical performance and mechanical reliability. Furthermore, with the introduction of fine-pitch area arrays, engineers could not get the 50-Ω socket contact into the inner array. The disadvantage for high-speed digital devices is the trace length is longer and there may be too much trace inductance in the ground/power contacts causing excessive switching noise and ground bounce. High-frequency gull wing contactors have controlled impedance contacts developed in flex circuit or microstrip techniques. To maintain good signal integrity, especially in automatic test equipment (ATE) environments, controlled impedance 50-Ω transmission allows the cleanest signal transfer and minimum of reflections, and 50-Ω contactors are commonly used for testing of gull wing package testing. A test socket's primary function is to transfer the signal between the device under test (DUT) and the system with the least amount of signal attenuation or degradation. On the other end of the socket spectrum, test sockets are individually machined to deliver outstanding electrical and precise mechanical placement and guiding. Comparison of standard pogo pin with a high-frequency pogo pin and ultra-high-frequency elastomer contacts used in test sockets. Consequently, the burn-in socket has contacts that are stamped, for high volume economic reasons, and it is designed to capture the device into the socket without the use of a clam-shell-style lid.įigure 1. To generate a statistically good reliability model, large numbers of devices need to be screened and as many as 10,000 sockets typically are needed. The goal in this application is to detect device failures based on extended thermal stressing for 24 to 72 hours without removing the part. ![]() Burn-in test times are long and the temperatures are high, usually 125☌. For example, burn-in sockets tend to be used in applications where the test signals are rather low frequency, usually a few kHz. Sockets vary widely in electrical and mechanical performance needed to support diverse test requirements within the overall product development process (Table 1). For high-speed serial links and emerging radio-frequency (RF) applications, however, engineers must replace the familiar pogo pin with more exotic contactors to ensure signal integrity and reliable performance (Figure 1). Within high-performance sockets, the pogo pin has remained the contact method of choice for 90 percent of applications. Different classes of sockets provide specialized electrical and mechanical parameters needed for specific steps in the product testing process. ![]() AND.HONGJUN YAOĪ socket is a critical element in the semiconductor product development and test environment. MOVING BEYOND POGO PINS BY NICK LANGSTON, NICK LANGSTON JR. ![]()
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