Loopback for System Testing Academic Supervision:

Many micro-electronic systems are based on transceiver architecture, as represented in Fig.1. Traditionally, the test methods are core-based, resulting in long test times and introducing some risks of affecting the signal integrity. In the core-based strategy, every block is tested against its own specifications, whereas path-based testing relies on system-level parameters. This new approach has been developed for some years, and represents a first step towards a full built-in-self-test (BIST) solution, the transmitter and the receiver being path-based tested. However, the test configuration still requires RF signal generation and capture, consequently high-performance instruments, contact blocks, probe cards, and test boards. The next step will rely on the so-called loopback technique. Some blocks of the transmitting path are used to generate the stimuli applied to the receiving blocks, which act as a digitizing + processing chain. Although this technique looks very attractive to solve the RF-related issues, still a lot of progress is required before its application to commercial products. The technical challenges may be considered twofold: 1. How to discriminate the errors generated by each block individually? 2. How to connect the transmitter to the receiver elements? In other terms, what are the (design-for-test) DfT solutions to be implemented without disturbing the application signals