A selt-testing BOST for high-frequency PLLs, DLLs, and SerDes

A built-off self-test (BOST) approach is described in which a self-testing FPGA on a device-under-test (DUT) interface board can test serializers or deserializers at serial rates up to 6.4 Gbps, and some SerDes at much higher rates. With a few on-chip undersampling latches, the same BOST can also test embedded PLLs, DLLs, clocks, and logic delays. For SerDes functions, the structurally tested parameters include jitter and its constituent components, jitter tolerance, and waveshape. For other embedded functions, the tested parameters include jitter, duty cycle, frequency, phase error, and delay. The hardware results show that picosecond resolution has been achieved, with minimal or no changes to the DUT.