PLL Filter

To obtain a reasonable level of long-term jitter, it is vital to supply the PLL with analog-grade power. An RC or RLC filter is used, where C is composed of multiple devices to obtain a wide spectrum of noise absorption. Although the circuit is simple, its effectiveness depends on specific board layout requirements. See Figure 1 for a typical power supply connection.

See Figure 1 for SerDes analog power connections. A high-precision 1.2 KΩ, 1% resistor in either a 0402 or 0201 package is required for the external reference resistor connected between SERDES_x_Lyz_REXT and SERDES_x_Lyz_REFRET.