What this clock buffer is and where it fits
The Cypress CY2304NZZXI-1 is a single-ended, non-PLL zero-delay buffer that distributes a single LVCMOS or LVTTL clock input to four LVCMOS outputs with matched propagation delays. It targets PCI Express (PCIe) reference clock distribution, buffering the single-ended reference. The 140 MHz maximum frequency covers PCIe reference clock rates. Packaged in an 8-TSSOP, it operates from 3V to 3.6V supply over -40°C to 85°C.
140 MHz and 1:4 fanout — what they mean for the clock tree
The 140 MHz maximum frequency is the ceiling for the output clock rate. The 1:4 input-to-output ratio means one input drives four outputs with matched delays. Because there is no PLL, the output frequency equals the input; there is no multiplication or jitter attenuation.
Non-differential I/O and PCIe — what works and what does not
The CY2304NZZXI-1 accepts LVCMOS or LVTTL inputs and outputs LVCMOS levels. It does not accept or generate differential signals. For PCIe clock distribution, the standard reference clock is a differential HCSL pair (100 MHz). This buffer cannot directly drive or receive that differential signal. However, many PCIe clock generators output a single-ended LVCMOS copy alongside the differential pair, and this part can fan out that single-ended copy to multiple endpoints that accept single-ended clocks. If your design requires differential HCSL fanout, look for a dedicated PCIe clock buffer with differential I/O. For single-ended LVCMOS clock trees, this part is a straightforward fit.
Supply and temperature — industrial-grade margin
The 3V to 3.6V supply range aligns with standard 3.3V logic rails. The -40°C to 85°C operating temperature covers industrial and extended-commercial conditions. No derating is needed within this range for the 140 MHz operation.
Package and footprint
The 8-TSSOP package is a common, low-profile surface-mount footprint. The 0.173-inch body width and 4.40 mm body length fit standard TSSOP-8 land patterns. No exposed pad — all eight pins are signal or power.
Lifecycle and compliance
The CY2304NZZXI-1 is listed as Active and ROHS3 Compliant. For new designs, this part is a safe selection today. ROHS3 compliance means it meets the latest EU restriction on hazardous substances, including all four phthalates.