A high-speed IC random-number source for SmartCard microcontrollers

The design of a high-speed integrated circuit random number source macro-cell, suitable to be integrated in a SmartCard microcontroller, is presented. The direct amplification of a thermal-noise source is exploited and an accurate and low-area offset zeroing system has been developed in order to increase the statistical quality of the output bit sequences. Moreover, an analytical model has been developed, allowing the estimation of the output bit correlation as a function of the main circuit parameters. Using a standard 0.18-μm n-well CMOS process, a prototype has been fabricated and measured, obtaining a random behavior for an output data rate up to 40 Mb/s. The macro-cell area, excluding pads, is 0.025 mm² (220 μm×116 μm) and its power consumption is about 3.6 mW when clocked at 10 MHz.