Toshiba International announces a new prototype reference clock oscillator fabricated with standard CMOS technology that achieves world-leading accuracy. Used to replace a conventional crystal oscillator, the new device developed by Toshiba Corporation will support the miniaturisation of electronic devices.
The increasing demand for the miniaturisation of electronic components has extended in recent years to oscillators, stimulating interest in ultra-small oscillators.
Although conventional crystal oscillators offer excellent accuracy of oscillation frequency, they require a relatively large package due to the size of the crystal. Smaller CMOS oscillators have been designed, but with a much lower oscillation frequency, due to large temperature dependence.
Toshiba has developed a technology for precise calibration of the temperature dependence of oscillation frequencies in CMOS oscillators. Its application has secured a high precision CMOS oscillator with accuracy of less than +/-100ppm (0.01%), comparable to crystal oscillators. Additionally, by taking advantage of the digital computing capability of CMOS, Toshiba has also achieved a wide range of frequency outputs (2-40MHz) in 40Hz steps. Conventional crystal oscillators output at a fixed frequency.
During the initial test, the oscillation frequencies of the CMOS oscillator are measured and calibrated at multiple temperatures, in order to realise high accuracy. The junction temperature can be quickly changed by an on-chip heater, realising low-cost testing and high-accuracy calibration.
Toshiba has therefore, developed a high-accuracy oscillator with thermal design using on-chip heater and stabilising temperature near the oscillator for the calibration. The digital calibration data, which is calculated and stored during the test, is automatically applied in actual operation.
Toshiba plans to commercialise the new CMOS oscillator within 2 to 3 years, and aims to reduce its volume to one third that of a conventional crystal oscillator. Toshiba will also integrate the oscillator into system LSI, such as MCU and ASIC.