Fast specification test of TDMA power amplifiers using transient current measurements

A novel test methodology for fast and accurate testing of RF power amplifiers used in wireless communication that employ time division multiplexing is presented. The steep cost of high frequency testers can be largely complemented by the proposed method due to its ease of implementation on low cost testers. TDMA power amplifiers usually have a control voltage to operate the device in various modes of operation. At each of the control voltage values, all the specifications of the power amplifier are measured to ensure the performance of each tested device. A new method is proposed to test all the specifications of these devices at different control voltage values by capturing the transient current response of their bias circuits to a time-varying control voltage stimulus. This results in shorter test times compared to conventional test methods. The test specification values are measured to an accuracy of less than 5% for all the specifications, and test time reduction of a factor more than 3 was achieved. The proposed test approach can specifically benefit production test of quad-band amplifiers (GSM850, GSM900, PCS/DCS), as a single transient current measurement can be used to compute all the specifications of the device in each of the modes of operation.