844002

FemtoClock® Crystal-to-LVDS Frequency Synthesizer 844002 DATASHEET GENERAL DESCRIPTION The 844002 is a 2 output LVDS Synthesizer optimized to generate Fibre Channel reference clock frequencies. Using a 26.5625MHz 18pF parallel resonant crystal, the following frequencies can be generated based on the 2 frequency select pins (F_SEL[1:0]): 212.5MHz, 187.5MHz, 159.375MHz, 106.25MHz and 53.125MHz. The 844002 uses IDT’s 3rd generation low phase noise VCO technology and can achieve <1ps typical rms phase jitter, easily meeting Fibre Channel jitter requirements.The 844002 is packaged in a small 20-pin TSSOP package. FEATURES Two LVDS outputs Selectable crystal oscillator interface or LVCMOS/LVTTL single-ended input Supports the following output frequencies: 212.5MHz, 187.5MHz, 159.375MHz, 106.25MHz and 53.125MHz VCO range: 560MHz - 680MHz RMS phase jitter @ 212.5MHz, using a 26.5625MHz crystal (637kHz - 10MHz): 0.65ps (typical) Full 3.3V or 2.5V supply modes 0°C to 70°C ambient operating temperature Available in lead-free (RoHS 6) package FREQUENCY SELECT FUNCTION TABLE Input Frequency (MHz) 26.5625 26.5625 26.5625 26.5625 23.4375 Inputs F_SEL1 F_SEL0 M Divider Value N Divider Value M/N Divider Value 0 0 24 3 0 1 24 4 1 0 24 6 1 1 24 12 0 0 24 3 8 6 4 2 8 Output Frequency (MHz) 212.5 (default) 159.375 106.25 53.125 187.5 (default) BLOCK DIAGRAM Pulldown F_SEL[1:0] nPLL_SEL Pulldown REF_CLK Pulldown 26.5625MHz XTAL_IN OSC XTAL_OUT nXTAL_SEL Pull...