Maxim provides a recommended PCB layout in the datasheet, but it's also important to follow general high-frequency PCB design guidelines, such as using a solid ground plane, minimizing trace lengths, and using 50Ω transmission lines for the RF signals.
To optimize the VCO tuning range, ensure that the tuning voltage (VTUNE) is within the recommended range (0.5V to 2.5V), and that the VCO is properly biased. Additionally, adjusting the values of the external resistors and capacitors can also help to optimize the tuning range.
The recommended power-up sequence is to first apply the analog supply voltage (VCC), followed by the digital supply voltage (VDD), and then the enable pin (EN). This ensures that the internal biasing and voltage regulators are properly initialized.
To reduce the phase noise of the PLL, ensure that the loop filter components are properly selected and that the PLL is operated within the recommended frequency range. Additionally, using a high-quality reference clock and minimizing the noise on the supply lines can also help to reduce phase noise.
The maximum operating temperature range for the LMX358AUA+ is -40°C to +85°C, but it's recommended to operate the device within a narrower range (e.g., 0°C to 70°C) for optimal performance and reliability.
LMX358AUA+ datasheet
by Maxim Integrated Products
