MAX15038 Datasheet, PDF (11/18 Pages) Maxim Integrated Products – 4A, 2MHz Step-Down Regulator with Integrated Switches

4A, 2MHz Step-Down Regulator
with Integrated Switches
Typical Application Circuit
INPUT
2.9V TO 5.5V
C6
C7
22µF
0.1µF
C5
2.2µF
R4
49.9kΩ
IN
BST
MAX15038
LX
V_DD
OUT
CTL2
CTL1
EN
FREQ
REFIN
SS
C4
0.022µF
PGND
FB
COMP
MODE
PWRGD
GND
C10
0.1µF
2.2Ω
L1
0.47µH
OPTIONAL
C15
1000pF
OUTPUT
1.8V, 4A
C3
560pF
R3
158Ω
C8
C9
22µF
0.01µF
C2
1500pF
R2
2.67kΩ
C1
33pF
V_DD
R1
20kΩ
Figure 1. 1MHz, All-Ceramic-Capacitor Design with V_IN = 2.9V to 5.5V and V_OUT = 1.8V
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
V_IN from 2.9V to 5.5V input supplies, making it ideal for
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
internal low-R_DS(ON) (24mΩ for the low-side n-channel
MOSFET and 31mΩ 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
(PWRGD) output goes high when V_FB reaches 92.5% of
V_REFIN and V_REFIN is greater than 0.54V.
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.
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