An Integrated Frequency Response Characterization System With a Digital Interface for Analog Testing

Current and future integrated systems demand cost-effective test solutions. In response to that need, this work presents a very compact mixed-signal test system. It performs the characterization of the magnitude and phase responses over frequency at multiple nodes of an analog circuit. The control inputs and output of this system are digital, enabling the test of the analog components in a system-on-chip (SoC) or system-in-package (SiP) through a low-cost digital automatic test equipment. Robust and area-efficient building blocks are proposed for the implementation of the test system, including a linearized analog multiplier for accurate magnitude and phase detection, a wide tuning range voltage-controlled oscillator and a low-power algorithmic analog-to-digital converter. Their individual design considerations and performance results are presented. A complete prototype in TSMC CMOS 0.35-mum technology employs only 0.3mm² of area. The operation of this test system is demonstrated by performing frequency response characterizations up to 130 MHz at various nodes of two different fourth-order continuous-time filters integrated in the same chip