844004AKI-104LFT

The Renesas 844004AKI-104LFT is a FemtoClock crystal-to-LVDS frequency synthesizer optimized for generating Fibre Channel reference clock frequencies. It accepts either an LVCMOS/LVTTL single-ended input or a parallel resonant crystal (18pF) as the reference. Using a 26.5625 MHz crystal, the device produces output frequencies of 212.5, 159.375, 106.25, or 53.125 MHz selected via the F_SEL[1:0] pins. With a 23.4375 MHz crystal, a default output of 187.5 MHz is available.

The synthesizer integrates a low phase noise VCO covering 560 MHz to 680 MHz, enabling typical RMS phase jitter of less than 1 ps at 212.5 MHz (integration range 637 kHz to 10 MHz). It provides four differential LVDS outputs, each with a dedicated divider. The device includes a PLL with bypass option, a phase detector, and divider circuitry M=24 fixed, N=3,4,6,12 depending on frequency selection.

Operating from a supply voltage of 2.375V to 3.465V, the 844004AKI-104LFT is rated for ambient temperatures from -40°C to 85°C. It is housed in a 32-pin VFQFN with an exposed pad (5mm x 5mm x 0.925mm, supplier package designation 32-VFQFPN) and is designed for surface mount assembly. The exposed pad enhances thermal dissipation for reliable operation across the temperature range.