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LM26480-Q1: GNd separation for LDO and the Buck circuit

Part Number: LM26480-Q1


I am currently designing power circuitry using LM26480-Q1 and I have question regarding the GND separation for this chip. 

As this chip has pin for core ground (GND_C) , LDO ground (GND_L) , and switching GND (GND_SW1, GND_SW2), what is the advised GND connection for this chip? Should I just separate the LDO circuit GND and buck circuit GND , then tie together with a net tie at a single point? Or should I just use this GND_L for low noise GND for LDO feedback , core GND for low noise GND for buck feedback, and rest tied to the SW GND? 

Sincerely ,


  • Hi Tsugumi,

      Please refer to its datasheet section "11.1 Layout Guidelines" and "11.2 Layout Example".

      Generally, core ground (GND_C) and LDO ground (GND_L) can be tied together, and switching GND should be separated since it may have much higher noise causing by buck switching; and then tie all GNDs together at a single point where is away from switch node and inductor.

      Also, it's important to make the switching GND traces as thick as possible for the lowest DRC.