A reliable precision clock source is absolutely necessary in complex SoCs. As the feature size becomes smaller and the speed of operation increases, the precision needed from the clock source becomes more and more important. Traditionally the clock is supplied by crystal oscillators. While crystal oscillators offer very good frequency stability, they tend to consume mAs of current for frequencies above 10MHz, have very slow start-up time (of the order of milliseconds), have high pin count, and take a lot of board area.
Cosmic Circuits’ innovative silicon oscillator solution addresses all these issues while providing a system clock which has a frequency accuracy better than that needed by most digital applications. Novel techniques have been used to reduce the frequency variation with supply and temperature. The silicon oscillator meets a frequency accuracy of better than ±1 percent across the full supply and temperature range (-40°C to 125°C). The architecture provides enough flexibility for generating a wide frequency range from 60MHz-250MHz without any external component while consuming very low power. The frequency can be programmed with 1MHz granularity in this range, enabling the user operate his system at the best possible speed. This frequency programming can be extremely helpful in systems that employ dynamic voltage and frequency scaling to optimize the system power and performance.
The silicon oscillators are designed to have a very low period jitter of ±1 percent and are immune to supply noise which makes them amenable to integration into complex digital SoCs. This oscillator has a very fast wake-up time (<50µs) from power up and also supports a very low power (<2.5µA) standby mode from which the oscillator can wake-up in <8µs, helping system designers to reduce power consumption. An automatic one time factory trimming option is provided for calibrating the process variations.
Cosmic Circuits
