Clock conditioning with integrated PLL — what the 1.296 GHz ceiling buys you
The LMK04000BISQX/NOPB is a Clock Conditioner — it cleans up and regenerates a reference clock using an integrated PLL. The maximum output frequency is 1.296 GHz, which places it in the range needed for high-speed serial links (Gigabit Ethernet, PCIe Gen 1/2, FPGA transceiver reference clocks) where jitter and phase noise matter. The PLL locks to an input from 0 Hz up to the rated max, and the device outputs up to seven copies of the conditioned clock via a 2:7 input-to-output ratio.
Signal standard support and supply rail tolerance
The device accepts LVCMOS, LVDS, and LVPECL inputs and outputs LVCMOS, 2VPECL, or LVPECL. All inputs and outputs are differential-capable, which is typical for high-frequency clock distribution where common-mode noise rejection is needed. The supply voltage range is narrow — 3.15 V to 3.45 V — so the 3.3 V rail must be regulated within ±4.5 %. A standard 3.3 V LDO with 1 % accuracy covers this comfortably, but a noisy switching regulator without post-filtering may push the rail outside the window.
Package and thermal — 48-WQFN with exposed pad
The part comes in a 48-lead WFQFN with an exposed pad, supplier device package 48-WQFN (7x7 mm).