Tool/software:
I have implemented a LM2678SD-5.0/NOPB in my design, and have run into some trouble. VIN = 24VDC, VOUT = 5VDC. I need 2 to 3A of output current but when attached to a load it will only output 800mA before the output voltage starts sagging down to 3V.
My schematic is basically identical to the app design in the datasheet. My CIN and COUT caps vary slightly and the Schottky diode is different due to obsolescence but should be sufficient. Below is the schematic and image of the layout. I have 10 PCB's on hand all exhibiting the same issue so I dont think it is workmanship. Is this controller very sensitive to minor changes in capacitor ESR etc?
Schematic:
Layout:
BOM of important parts:
| C4 | CAP CER 0.01UF | Kemet | C0805C103J5RAC7210 | |
| L2 | FIXED IND 27UH 5A 40 MOHM SMD | Bourns | SRR1210A-270M | |
| C7, C13 | CAP ALUM 150UF 20% 35V SMD | Nichicon | EEE-FK1E151AL | |
| D15 | DIODE SCHOTTKY 60V 7A TO277A | Vishay | SS10P6-M3/87A |
Any assistance you could give ASAP would be much appreciated.
