An improved digital output buffer for a digital temperature sensor with an I2C high speed interface

Abstract

An improved digital open drain output buffer is designed in a 0.18µm CMOS process. The circuit can operate in a wide range of power supply voltages, from 1.5V to 5.6V. This output buffer is used in an I²C High Speed Interface, allowing for a transmission rate of 3.4 Mbps, with a data hold time of 39.4ns at 1.5V, and 30.4ns at 5.6V. This interface is implemented in a digital temperature sensor. These performances were achieved through topology changes to a classic digital output buffer. The proposed circuit achieves a two times faster response time when transmitting data from the sensor, compared to the standard topology.