Agilent Measurement Journal - Issue 5 - 2008 - (Page 65)

O Optimizing the cost of test in a high-volume production environment has always been a formidable challenge for manufacturers, especially because test costs can be a signiﬁcant percentage of overall product cost. One example is in mobile handset testing. According to IDC’s Worldwide Quarterly Mobile Phone Tracker, global shipments of mobile handsets reached the one billion unit milestone in 2006. The actual shipment number — 1.019 billion — represented a 22.5 percent growth over the 832.8 million units shipped in 2005. This impressive growth intensiﬁes the importance of reliability and performance in the automated test systems (ATS) used for mobile-phone testing. Consequently, high-volume component manufacturers are always looking for test solutions that are not only cost effective in terms of throughput, but that also provide the highest accuracy and performance. Furthermore, the explosive growth in the very large scale integration (VLSI) arena, coupled with the need to squeeze more features and functionality into a single component requires expanded test coverage to cover both DC and the RF spectrum. Test systems and solutions have become highly complicated switching boxes or modules that guarantee the high level of accuracy, performance and reliability needed to meet the requirements of automated testing. Ultimately, this translates into a higher premium being placed on lower cost of ownership for these types of systems. Consequently, there is a strong need for multiple switches capable of providing the various routings of test paths between DUTs and test and measurement systems with a guaranteed level of precision (switching repeatability) and accuracy (RF speciﬁcations). The emphasis is also on switch operating life and reliability. Long life, repeatability and reliability directly lower the cost of ownership by reducing calibration cycles, increasing test-system uptime and ensuring ATS measurement integrity over time. As a result, operating life and repeatability of generic electromechanical (EM) switches have now become the two most critical properties that determine the total cost of ownership of ATS (see the sidebar, Switch types). However, the mechanical nature of the EM switching mechanism means that their life, precision and reliability are dependent on the switch design, mechanism and materials, as well as the process control used during mass production. As a result, careful consideration must be given to these factors when selecting an EM switch. Switch types There are basically two major types of connectorized RF and microwave switch modules: electromechanical (EM) switches, which rely on mechanical contacts as their primary switching mechanism, and solid-state switches. The latter category is comprised of ﬁeld-effect transistors (FETs) and PIN diodes. FET switches create a channel (depletion layer) that allows current to ﬂow from the drain to the source of the FET. The PIN diode consists of a highresistivity intrinsic (I) layer that is sandwiched between highly-doped positively (P) charged material and negatively (N) charged material. Selecting which type of switch to use depends on the application. EM switches are often preferred due their very low insertion loss, high powerhandling capability and excellent immunity to electrostatic discharge (ESD). Agilent Measurement Journal 65

Table of Contents Feed for the Digital Edition of Agilent Measurement Journal - Issue 5 - 2008

Agilent Measurement Journal Issue 5 Finding a New Path when Assumptions Break Down Contents Testing MIPI D-PHY Protocols Oscilloscope Firmware Update DNA Replication Joining the LTE/SAE Trial Initiative Testing Proteins Praise for DC Power Analyzer Scripting Features for AMDS Testing Hybrid PCBA Systems Improving the Gene Expression System Workflow Turning a “Good Enough” Test Strategy into One That’s Reliable, Repeatable and Traceable Understanding the Effects of Limited-Bandwidth Channels on Digital Data Signals Introducing the 3GPP LTE Downlink Validating the 26 Validating the Physical and Protocol Layers in DDR Memory Interfaces Understanding Total Jitter Measurements of Low Probabilities Using Behavioral-Model Simulation to Accurately Predict First-Order PLL Performance Creating Synchronous High-Frequency Sampling across Multiple Digitizers Overcoming the Challenges of Testing FlexRay Networks Understanding Operating Life and Repeatability of Electromechanical Switches and their Effect on Total Cost of Ownership Implementing Micro and Nano LC/MS Techniques for High Sensitivity Lipidomics Analysis

Agilent Measurement Journal - Issue 5 - 2008

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