48-WQFN footprint and thermal story
The LMK03200ISQX/NOPB comes in a 48-WFQFN with an exposed pad (7x7 mm body, supplier package 48-WQFN). Without that via cluster, the junction temperature rises faster under the 3.45 V rail at the 1.296 GHz output rate.
What the 1:8 fanout and 1.296 GHz ceiling mean for the clock tree
This is a clock conditioner — it takes a single reference (LVCMOS, LVDS, or LVPECL) and distributes eight differential outputs (LVDS or LVPECL) at up to 1.296 GHz. There is no internal PLL, so the output frequency equals the input frequency; the device cleans jitter and buffers the signal, it does not synthesize a new frequency. For a system clock tree, the 1:8 ratio means one oscillator or TCXO feeds eight high-speed lanes without needing separate fanout buffers. Because the part lacks a PLL, the input clock quality directly sets the output jitter floor. The conditioner's additive jitter is low enough for most ADC/DAC and FPGA reference applications, but the input must already be within the target frequency tolerance — there is no frequency multiplication or division available.
Supply rail tolerance and decoupling
The voltage supply range is 3.15 V to 3.45 V — a tight 300 mV window. Place a 0.1 µF ceramic cap within 2 mm of each supply pin, plus a bulk 10 µF cap near the exposed-pad via cluster. The high-frequency output edges draw transient current that the local decoupling must supply.
Industrial temperature grade and deployment envelope
The 48-WQFN package with exposed pad is MSL-3 typical for this class; bake before reflow if the sealed reel seal is broken and the floor life is exceeded.