Methods and apparatuses for generating random numbers based on bit cell settling time

Abstract

One feature pertains to a true random number generator that utilizes the settling time of a bit cell as an entropy source to generate random digital output values. The bit cell may be a static random access memory bit cell. The bit cell's settling time may be converted into a digital output using an analog to digital converter. A plurality of bit cells may serially couple to one another in a ring formation. The bit cell ring can then be enabled such that each bit cell of the plurality of bit cells achieves a settling value that activates the subsequent bit cell in the ring causing it to in turn reach a settling value, and so on. An output node of one of the bit cells in the ring can then be sampled using a flip-flop to generate a continuous stream of random bits.