Efficient test strategy for TDMA power amplifiers using transient current measurements: uses and benefits

Abstract

A novel algorithm for fast and accurate testing of TDMA power amplifiers in a transmitter system is presented. First, 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. Secondly, 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 using the transient current response of their bias circuits to a time-varying control voltage stimulus. These 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 measured. 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 different modes of operation, over different operating frequencies.