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Split cap on LT3045

Hello,

I am using LT3045 for low noise power supply generation. Following the PCB layout guidelines I used the "split caps" technique for the output capacitor. I understood that this is a sort of Kelvin connection, but I cannot fully explain the physical reason behind the high frequency noise filtering, as said in the UG. Can someone give me an explanation?

  • What is meant is that you physically separate the PCB pad into two pieces such that noise on one of the halves does not travel to the other half. If there is noise present in the connection between the IN cap ground pin and the OUT cap ground pin, the extra impedance from the split will reduce the amount that goes into the connection between the SET cap ground pin and the OUT cap ground pin

  • Just wondering, if it pads 3 and 4 are interchangeable in their position? In the data sheet schematic LT3045 , OUT connects to the split capacitor physically opposed to GND. The "sense part " of the split cap is physically between OUTS and the GND side of the set pin capacitor. However, on the pcb picture above it s different.

    The complimentary neg LDO LT3094 is more consistent in its data sheet recommended PCB layout. So I wonder if there is any importance which pad is physically opposed to OUTS?