C10

0.1

µF

C6

22

µF

OUTPUT

1.8V, 4A

INPUT

2.9V TO 5.5V

C7

0.1

µF

C5

2.2

µF

BST

LX

OUT

IN

CTL2

CTL1

PGND

FB

C1

33pF

C2

1500pF

R1

20k

Ω

R2

2.67k

Ω

COMP

L1

0.47

µH

C3

560pF

C4

0.022

µF

R4

49.9k

Ω

C8

22

µF

C9

0.01

µF

R3

158

Ω

PWRGD

EN

FREQ

REFIN

SS

GND

MODE

MAX15038

2.2

Ω

C15

1000pF

OPTIONAL

Detailed Description

The MAX15038 high-efficiency, voltage-mode switching

regulator delivers up to 4A of output current. The

MAX15038 provides output voltages from 0.6V to 0.9 x

on-board point-of-load applications. The output voltage

accuracy is better than ±1% over load, line, and tem-

perature.

The MAX15038 features a wide switching frequency

range, allowing the user to achieve all-ceramic-capaci-

tor designs and fast transient responses (see Figure 1).

The high operating frequency minimizes the size of

external components. The MAX15038 is available in a

small (4mm x 4mm), lead-free, 24-pin thin QFN pack-

age. The REFIN function makes the MAX15038 an ideal

candidate for DDR and tracking power supplies. Using

MOSFET and 31m

Ω for the high-side n-channel

MOSFET) maintains high efficiency at both heavy-load

and high-switching frequencies.

The MAX15038 employs voltage-mode control architec-

ture with a high bandwidth (28MHz) error amplifier. The

voltage-mode control architecture allows up to 2MHz

switching frequency, reducing board area. The op-amp

voltage-error amplifier works with type III compensation

to fully utilize the bandwidth of the high-frequency

switching to obtain fast transient response. Adjustable

soft-start time provides flexibilities to minimize input

startup inrush current. An open-drain, power-good

The MAX15038 provides option for three modes of oper-

ation: regular PWM, PWM mode with monotonic startup

into prebiased output, or skip mode with monotonic

startup into prebiased output.

Typical Application Circuit

4A, 2MHz Step-Down Regulator

with Integrated Switches

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