Slide 1 Slide 2 Slide 3 Slide 4 Slide 5 Slide 6 Slide 7 Slide 8 Slide 9 Slide 10 Slide 11 Slide 12 Slide 13 Slide 14 Slide 15 Slide 16 Slide 17 Slide 18 Slide 19 Slide 20 Slide 21 Slide 22 Slide 23 Product List
SIMPLE SWITCHER Wide Vin Synchronous Regulator Overview Slide 10

Proper PC board layout for Switched Mode Power Supplies (SMPS) is critical to achieve proper converter operation, good thermal performance, and excellent radiated EMI performance. Optimized board layout for low radiated EMI is made very simple by the package and pin arrangement of the SIMPLE SWITCHER® synchronous buck converter family; LM4360x and LM4600x. The pin-out in this family of devices is designed to enable optimized PCB layout with best EMI and thermal performance. The VIN and PGND location allows for the input cap to be placed as close as possible to the package. The SW pin is on the other side, so there is no need for the input cap to jump over the SW node. The loop area formed by the input cap, VIN, and PGND pins is minimized and makes long runs to low impedance nodes, short runs to high impedance nodes possible; place the output voltage divider close to the FB node (high impedance), farther from Vout (low impedance). With LM4360x/LM4600x, the FB Pin is in the corner, shielded by AGND and away from noise sources, this makes it easy to place the divider right next to the FB pin, keeping this node as small as possible. Gate drives are also high di/dt paths; keep CBOOT and CVCC bypass caps very close to the device pins to minimize loop area (inductance) in the high di/dt loop. In the LM4360x/LM4600x, the BOOT pin is located right next to SW which allows for close CBOOT placement with smallest possible loop area (lowest inductance), plus the VCC pin is next to BOOT.

PTM Published on: 2015-03-06