Time-Based Embedded Test Instrument with Concurrent Voltage Measurement Capability

A scalable low -overhead on-chip instrument is proposed for analog and mixed-signal (AMS) systems-on-chip (SOC) testing, capable of making concurrent low-frequency voltage measurements. It addresses the limitation of parallel testing while reducing the test cost associated with automatic test equipment (ATE). The architecture is based on the distributed voltage-to-time conversion, followed by centralized time-to-digital conversion processes. The voltage to time conversion is achieved using the pulse-width modulation, via network of multiple sensors deployed throughout the SOC. Outputs of the time-to-digital converter are accessed via serial communication bus. Ease of scalability of instrument’s capabilities to perform more concurrent voltage measurements outweighs the fact that it does not achieve high sampling rates. An optional multiplexing scheme reduces size of the test bus that has to be routed around the CUT. Implemented instrument, with 14 sensors, is evaluated in a test case that involves multiple linear and switch mode circuits.