ASM5I9774A

The ASM5I9774A is a low-voltage high-performance 125MHz PLL-based zero delay buffer designed for high-speed clock distribution applications.

The ASM5I9774A features two reference clock inputs and provides 14 outputs partitioned in 3 banks of 5, 5, and 4 outputs. Bank A and Bank B divide the VCO output by 4 or 8 while Bank C divides by 8 or 12 per SEL(A:C) settings, see Functional Table. These dividers allow output to input ratios of 6:1, 4:1, 3:1, 2:1, 3:2, 4:3,  1:1, and 2:3. Each LVCMOS compatible output can drive 50? series or parallel terminated transmission lines. For series terminated transmission lines, each output can drive one or two traces giving the device an effective fanout of 1:28.

The PLL is ensured stable given that the VCO is configured to run between 200 MHz to 500 MHz. This allows a wide range of output frequencies from 8.3 MHz to 125 MHz. For normal operation, the external feedback input, FB_IN, is connected to the feedback output, FB_OUT. The internal VCO is running at multiples of the input reference clock set by the feedback divider, see Frequency Table.

When PLL_EN is LOW, PLL is bypassed and the reference clock directly feeds the output dividers. This mode is fully static and the minimum input clock frequency specification does not apply.