RF Test Gage R&R Improvement
Advanced cell phone architectures require high performance multi-throw RF switches. Reliably measuring the very low RF power levels of the third harmonic signal of these switches is a significant challenge. This paper discusses the use of Gage studies to identify and measure the sources of variation in RF probe measurements. Tester Gage study results are presented. Evaluations of factors including test instrument repeatability, probe card wear, probe tip planarity, probe pressure, and probe placement within the bond pad are presented. The data indicated the repeatability of the test instrumentation was very good. However, the reproducibility needed improvement. The most significant factor in achieving reproducible RF measurements is sufficient probe contact. A method to provide probe operators feedback of sufficient probe contact was developed and implemented. As a result, the Gage study passed. Further, the percentage of die requiring re-test was reduced significantly. INTRODUCTION State of the art multi-throw RF switches need to meet third harmonic performance specifications in the range of -30 to -40 dBm power at RF frequencies in the range of 824 to 915 MHz. -30 and -40 dBm correspond to 1uW and 100nW of power respectively. To provide known good switch die for Skyworks Front End Modules (FEM), the Skyworks pHEMT wafer fab performs RF probe testing on all switch die. Reliably making these low power measurements at high frequencies in a probe test environment requires advanced test instruments and rigid production discipline. The Skyworks Quality System requires Gage studies be performed on all measurement equipment. Further, Skyworks customers can and do request measurement system Gage study results.
Statistical measurement system analysis of over-the-air measurements of antenna array at 28 GHz
Next generation communication systems will use millimeter wave communication to enable higher data rates compared to Long Term Evolution (LTE) system. The coming 5G system will use antennas antenna arrays and multiple radio transceivers to compensate an excess radio signal path loss and conductive testing of an antenna array will be a challenge. Overthe-air (OTA) testing provides solution to cabling and connection problems. This paper provides an analysis of accuracy of OTA measurement at 28 GHz frequency band. A statistical measurement system analysis is used and results show that ± 0.89 dB measurement accuracy is achieved in a typical laboratory environment without an anechoic RF chamber.
Product Sensitivity Analysis on Multithrow TX/RX Switches
A method for data alignment of device characteristics as measured on Process Control Monitors (PCM) with the circuit level performance of adjacent multithrow switch circuits has been developed. This technique provides a powerful method for correlating extrinsic and intrinsic device characteristics with circuit performance. This method provides a valuable tool that is being used to improve device modeling, device development and production yields.