NB650/NB650H

– 6A, 28V, FAST-TRANSIENT, SYNCHRONOUS STEP-DOWN CONVERTERS

NB650/NB650H Rev. 1.13

www.MonolithicPower.com

19

10/7/2019

MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.

Preliminary Specifications Subject to Change

© 2019 MPS. All Rights Reserved.

LAYOUT RECOMMENDATIONS

1. Place the high current paths (GND, IN, and

SW) as close to the device as possible with

direct, short, and wide traces.

2. Use a 0.1

μF input decoupling capacitor to

connect the IN and GND pins. Put the input

decoupling capacitor and input capacitors as

close to the IN and GND pins as possible.

3. Put the VCC decoupling capacitor as close to

the VCC and GND pins as possible.

4. Keep the switching node SW short and away

from the feedback network.

5. Place the external feedback resistors next to

the FB pin. Make sure that there is no via on

the FB trace.

6. Keep the BST voltage path (BST, CBST, and

SW) as short as possible.

7. Connect the bottom IN and SW pads to large

copper areas to achieve better thermal

performance.

8. Use a four-layer layout to achieve better

thermal performance.

SW1

C2

L1

R3

R2A

R3

C4

R3

R4

SW

SW

IN

PGND

PGND

BST

PG

EN

VID1

VID2

VCC

AGND

SS

FREQ

RFB1

FB

RFB2

IN

PGND

PGND

SW

SW

1

2

3

4

8

7

6

5

9

10

11

12

13

14

15

16

17

GND

VIN

VOUT

SW

GND

Top Layer

GND

SW

Inner1 Layer

GND

SW

Inner2 Layer

GND

VOUT

SW

C6

R3

R6

Bottom Layer

Figure 16: PCB Layout Guide