MP2321 – 19V, 2A, LOW IQ, STEP-DOWN CONVERTER

MP2321 Rev. 1.1

www.MonolithicPower.com

19

5/24/2019

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

© 2019 MPS. All Rights Reserved.

PCB Layout Guidelines

Efficient layout of the switching power supplies

is critical for stable operation. A poor layout

design can result in poor line or load regulation

and stability issues. For best results, refer to

Figure 14 and follow the guidelines below.

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

SW) very close to the device with short,

direct, and wide traces.

2. Place the input capacitor as close to IN and

GND as possible.

3. Place the mode/frequency circuit close to

the part.

4. Place the external feedback resistors next

to FB.

5. Keep the switching node (SW) short and

away from the feedback network.

For better performances, it is recommended to

use four-layer boards. Figure 14 shows the top

and bottom layers (Inner 1 and Inner 2 are both

GND).

sw

VOUT

GND

VIN

R1

R2

GND

C1A

C1B

C2A

C2B

R5

R7

R6

C3

C4

Rb

Cb

R3

L

C1

Figure 14: Sample Board Layout

Design Example

Table 3 shows a design example when ceramic

capacitors are applied.

Table 3: Design Example

VIN

12V

VOUT

1.2V

IOUT

2A

The detailed application schematic is shown in

Figure 15 through Figure 21. The typical

performance and waveforms are shown in the

Typical Characteristics section. For more

devices applications, please refer to the related

evaluation board datasheet.