Clock Generator Chip Raises Jitter Performance Bar

The CDCE421 low-phase-noise low- voltage positive emitter coupled logic/low-voltage differential signaling (LVPECL/LVDS) clock generator from Texas Instruments provides 380-fs (rms at 10 kHz to 20 MHz) jitter performance (see the figure).

The generator’s crystal-oscillator/frequency synthesizer supports output frequencies from 10.9 to 766.7 MHz and from 875.2 to 1175 MHz for Ethernet, Fibre Channel, PCI Express, and Serial ATA products.

For design flexibility, the chip integrates EEPROM, crystal oscillator circuitry, and a programmable loop filter from 50 to 400 kHz on-chip. All device settings are programmable through a serial interface for programming after manufacturing.

The CDCE421 operates in a 3.3-V supply environment from –40°C to 85°C. Available in bare die or other packaging options, it’s priced at $7.00 in quantities of 1000.