DDR clock generator with 200 MHz PLL and 1:18 fanout
The Cypress CY28347ZC is a processor-specific PLL clock generator designed for DDR memory subsystems. It accepts a single clock input and distributes up to 18 clock outputs at frequencies up to 200 MHz, with differential signaling on both input and output sides — the signal type DDR controllers and DIMMs expect for clean edge rates at that speed. The 1:18 fanout means one part can clock an entire multi-rank DDR memory array or a multi-core processor cluster, reducing the number of clock buffers on the board. The single-circuit PLL locks to the reference and delivers low-jitter copies across the 18 outputs. Operating temperature is rated 0°C to 70°C, which covers commercial equipment — servers, workstations, networking gear, and office electronics. Not rated for industrial or automotive under-hood environments.
Differential I/O — what it means for signal integrity
Both input and output are differential (Yes/Yes). That tells you the part expects a differential reference clock — typically from an oscillator or another PLL — and delivers differential pairs to each DDR DRAM or controller. At 200 MHz, differential routing keeps common-mode noise out of the clock tree and maintains the tight skew budget DDR requires.
Lifecycle and supply posture
That removes the urgency for a last-time-buy or a hasty redesign — the part can be specified into new BOMs with confidence. RoHS non-compliant per the listing — factor that into any EU or RoHS-mandated BOM review.