Low cost implicit built-in self-test of passive RFID Tags

Testing of RFID Tags is complicated by the fact that the RFID chips must be tested both before and after antenna attach. The test procedure prior to chip attach must ensure, to the maximum extent possible, that any defects in the chip that can cause failure after antenna attach are detected with very high failure coverage. The test procedure after antenna attach must ensure that no failures are injected into the system during the antenna attach procedure itself. In both cases, the metric of performance that the RFID system is assessed against, is the maximum distance between the tag reader and the RFID tag at which reliable communication is established between the two. Since RFID tags are extremely low cost, BIST techniques for both test procedures are developed for inductively coupled RFID tags (ISM Band of 13.56 MHz) that are ultra low cost and require minimal hardware overhead (to justify cost considerations). It is shown that high manufacturing failure coverage is achieved with very low BIST overhead.