What is the AD9508BCPZ-REEL7?
The AD9508BCPZ-REEL7 is a 1:4 fanout buffer and clock divider from Analog Devices, accepting a single CMOS input and distributing it to four outputs configurable as CMOS, HSTL, or LVDS. It operates up to 1.65 GHz, making it suitable for distributing high-speed reference clocks to multiple ADCs, DACs, or FPGAs in a clock tree.
The 1.65 GHz maximum frequency sets the upper bound for the input clock rate. For a 1 GHz reference clock, the part has 650 MHz of margin, but at 1.6 GHz the jitter performance will be closer to the datasheet limits. The 1:4 fanout ratio means one input drives four loads directly, saving external fanout buffers and reducing PCB area. The differential input/output capability allows the part to handle LVDS or HSTL signals natively, which is essential for low-jitter distribution in high-speed converter systems. Supply voltage spans 2.375 V to 3.465 V, covering common 2.5 V and 3.3 V rails. The wide range gives flexibility in mixed-voltage systems, but the output swing will track the supply — a 2.5 V rail produces a smaller CMOS swing than 3.3 V, which may affect noise margin at the receiver.
The exposed pad also serves as the ground return for the die, so a solid via array to the ground plane is recommended.