48-pin WQFN with exposed pad — board integration story
The LMK03033CISQX/NOPB comes in a 48-WFQFN exposed pad package (7x7 mm, 0.5 mm pitch). The exposed pad underneath must be soldered to a thermal land on the PCB — it's the primary heat path for the die, not just a mechanical anchor. Without a proper via array to the ground plane, the junction temperature climbs fast when the device is distributing a 2.16 GHz clock to eight outputs. Decoupling caps need to be close to each supply pin; the narrow tolerance means any ripple on the rail shows up as jitter on the output clocks.
2.16 GHz clock distribution — what the 1:8 fanout means
This is a clock conditioner, not a PLL synthesizer — the PLL flag is No. It takes a clean reference clock (LVCMOS, LVDS, or LVPECL) and fans it out to eight differential outputs (LVDS or LVPECL) at up to 2.16 GHz. The 1:8 ratio means a single input drives eight clock trees, each with matched skew. The divider/multiplier is Yes/No — there's a divider on the output path but no frequency multiplication. If your system needs a 100 MHz reference and you feed it a 100 MHz oscillator, the outputs are 100 MHz divided down. No PLL means no loop filter, no lock time, and no phase noise from the PLL itself — the output jitter is essentially the input jitter plus the buffer noise floor. Operating from -40°C to 85°C, it covers industrial environments — base stations, test equipment, and data center switches where the ambient inside the chassis can hit 70°C with airflow.
The base product number is LMK03033 — the /NOPB suffix indicates lead-free (RoHS-compliant) finish.