Hard Disk Drive Applications

USB flash drive Hard disk drive Display/Digital TV Printer Spread Spectrum Clocking

Mobius CHO:

First commercial replacement of quartz crystals in a USB FS interface.
First all-CMOS oscillator to match the accuracy, phase noise and jitter performance of quartz-based crystal oscillators
An all-CMOS, integrated clock with the fastest start-up time
The first, fully integrated Spread Spectrum Clock Generator that eliminates the need for both quartz crystals and PLL ICs.

Design Considerations

Mobius Microsystems’ CMOS Harmonic Oscillator™ (CHO) is a simple, robust and reliable frequency reference for Hard Disk Drives. The MM8101 series of products replace the commonly used 25, 30, 40, 50 and 75MHz crystals and crystal oscillators to simplify system design, reduce start-up latency and failure rates. The devices are built in standard CMOS process, and assembled in low profile plastic packages and offer excellent reliability on hard-disk drive applications. Conventional quartz resonators require an external oscillation circuit, which commonly resides in the channel SoC on a hard drive. On such architecture, the mismatches in oscillator circuit characteristics and resonator requirements, noisy PCB traces, and other factors could lead to crystal start-up problems. In the CHO architecture, there are no mechanical resonators, and no oscillator circuit is needed, thus simplifying hard-disk PCB design, eliminating start-up problems, and improving reliability.

Block Diagram

Mobius Products

MM8101-25
MM8101-40
MM8101-50
MM8101-75

Application Notes

Coming soon...

Interfaces Supported

S-ATA Gen1/150
S-ATA Gen2/350
S-ATA Gen3/650