The LMK61E08 family of ultra-low jitter PLLatinum™ programmable oscillators uses fractional-N frequency synthesizers with integrated VCOs to generate commonly used reference clocks. The output on LMK61E08 can be configured as LVPECL, LVDS, or HCSL. The device features self-start-up from on-chip EEPROM to generate a factory-programmed default output frequency, or the device registers and EEPROM settings are fully programmable in-system through an I2C serial interface. The device provides fine and coarse frequency margining control through an I2C serial interface, making it a digitally-controlled oscillator (DCXO). The PLL feedback divider can be updated to adjust the output frequency without spikes or glitches in steps of <1ppb using a PFD of 12.5 MHz (R divider=4, doubler disabled) for compatibility with xDSL requirements, or in steps of <5.2 ppb using a PFD of 100 MHz (R divider=1, doubler enabled) for compatibility with broadcast video requirements. The frequency margining features also facilitate system design verification tests (DVT), such as standards compliance and system timing margin testing.