Reducing Routing Overhead by Self-Enabling Functional Path Ring Oscillators

Automotive Microcontrollers (MCUs) are extensively tested to guarantee zero-defect quality. Performance screening is one of the critical factors to ensure that MCUs meet quality requirements. Ring Oscillator (RO) structures are used for this performance screening. Such RO structures usually cause routing overhead on the chip. The routing overhead increases, especially when many ROs are implemented. This paper presents a novel self-enabling technique that significantly reduces the routing overhead for functional path ROs. We present a proof of concept on a large automotive MCU. The routing overhead can be reduced by over 80% compared to traditional approaches.