A 25MHz all-CMOS reference clock generator for XO-replacement in serial wire interfaces

A 25MHz all-CMOS clock generator is demonstrated where measured performance makes it suitable for direct replacement of the reference crystal oscillator (XO) for serial wire interfaces. Fabricated in a 0.25μm 1P5M logic CMOS process, and with no external components, the developed clock generator dissipates 59.4mW while exhibiting ±152ppm frequency error over process, ±10% variation in the power supply voltage and from −5–75oC. Nominal period jitter and power-on start-up latency are 3.93ps
rms
and 268μs respectively.