LMH1219: the power supply of LMH1219

Hi Jianguo,

VDD_LDO is always 1.8V. Setting VDD_LDO depends on whether you operate in Single Supply 2.5V mode or Dual Supply 2.5V/1.8V Mode.

• Single Supply 2.5V Mode: Provide 2.5V to VIN. When this is done, VDD_LDO is an output, so you will only need an external 1uF and 0.1uF bypass capacitor to VSS. Do NOT provide 1.8V to VDD_LDO, since VDD_LDO is an LDO output in this mode.
• Dual Supply 2.5V/1.8V Mode: Provide 1.8V to VIN and VDD_LDO. Meanwhile, provide 2.5V to VDD_CDR and VDDIO.

For more information. refer to Section 9 of the datasheet (Power Supply Recommendations).

Thanks,

Michael