A Flash-based Digital to Analog Converter for Low Power Applications

This paper presents a novel technique for digital to analog conversion, which uses flash transistors embedded in a traditional current-steering digital to analog converter (DAC) architecture. Our design utilizes flash transistors as programmable, tunable current sources. Our DAC achieves extremely low latency, area, and power, making it especially suited for the internet of things (IoT) and other applications with a highly constrained resource budget. In addition, the use of flash transistors allows a user to cancel errors due to process/voltage variations and chip aging. This tuning can be performed in the fabrication facility, or in-field. We perform a Monte-Carlo analysis to demonstrate the performance of our DAC in a real-world context. Compared to recent DACs intended for use in IoT devices (or for applications that are highly resource constrained), we significantly improve error metrics. We reduce chip area by 4.3× compared with the smallest DAC intended for IoT. Additionally, we improve throughput by 55 ×and energy per conversion by 33×, compared with the fastest and the most energy efficient DAC intended for IoT, respectively. The proposed 12-bit DAC achieves a throughput of 100 MS/s, an energy per conversion of 36.6 fJ. Based on Monte Carlo analysis, we report a maximum INL (DNL) of 1.242 LSB (0.757 LSB), an average INL (DNL) of 0.286 LSB (0.088 LSB), an ENOB of 11.80 bits, and an SFDR of 82.89 dB.