What this part does — clock fanout for a 9-load bus
The Infineon (Cypress) CY2309SXC-1H is a single-chip fanout buffer and zero delay buffer that takes one LVCMOS or LVTTL input and distributes it to nine LVCMOS outputs. The internal PLL can be bypassed, letting the part act as a simple clock buffer or as a zero-delay repeater that aligns the output edges to the input. Maximum output frequency is 133.33 MHz, which covers most common processor, memory, and peripheral clocks up to that speed. Supply range is 3V to 3.6V, and the part is rated for commercial temperature environments (0°C to 70°C). It comes in a 16-SOIC package — a standard footprint that fits existing PCB layouts without a board spin.
1:9 fanout — what it means for your clock tree
The 1:9 ratio is the key selection parameter: one input drives nine loads. If your board has fewer than nine clock destinations, you can leave the unused outputs floating (they are LVCMOS, not open-drain). If you need more than nine, you cascade two CY2309SXC-1H parts or step up to a higher-fanout buffer. The non-differential I/O (LVCMOS in, LVCMOS out) means this part is for single-ended clock distribution, not differential pairs like LVPECL or LVDS. That keeps the BOM cost down but limits the maximum trace length before signal integrity degrades — keep the fanout runs short and impedance-controlled.
PLL with bypass — when to use each mode
The PLL can be enabled for zero-delay operation (the output edges align to the input, useful when the clock goes through a long trace or a series-termination resistor that introduces phase shift) or bypassed to treat the part as a simple buffer with no phase adjustment. Bypass mode is lower power and lower jitter because the PLL loop is off. If your system already has a clean clock source and you just need to split the signal to multiple loads, bypass is the right call. If you need to compensate for board-level delay, enable the PLL. The part does not have a divider or multiplier — the output frequency equals the input frequency in both modes.
Temperature grade and environment
Rated 0°C to 70°C, this is a commercial-grade part.
Lifecycle and supply posture
The CY2309SXC-1H is listed as Active and ROHS3 compliant. There is no last-time-buy notice, no NRND flag, and no official successor. For a BOM line that needs this exact 1:9 fanout in a 16-SOIC commercial-grade package, the part is available through independent distribution and quoted to order against an RFQ.