On-Chip Multi-Channel Waveform Monitoring for Diagnostics of Mixed-Signal VLSI Circuits

Abstract

The multi-channel waveform monitoring technique enhances the built-in test and diagnostic capability of mixed-signal VLSI circuits. An 8-channel prototype system incorporates adaptive sample time generation with a 10-bit variable step delay generator and algorithmic digitization with a 10-bit incremental reference voltage generator. The prototype, in a 0.18-/spl mu/m CMOS technology, demonstrated on-chip waveform acquisition at 40-ps and 200-/spl mu/V resolutions. The waveforms were as accurate as those by an off-chip measurement technique, while more than 95% reduction of the waste time in waveform monitoring was achieved. The area of 700 /spl mu/m /spl times/ 600 /spl mu/m was occupied by a single waveform acquisition kernel that was shared with eight front-end modules of 60 /spl mu/m /spl times/ 200 /spl mu/m each. The developed on-chip multi-channel waveform monitoring technique is waveform accurate, area efficient, and low cost, which are all requisite factors for a diagnosing methodology toward mixed analog and digital signal integrity in the system-on-chip era.