Rainbow Electronics MAX17083 - Manual (Page 8)

MAX17083
Low-Voltage, Internal Switch,
Step-Down Regulator
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Detailed Description
The MAX17083 standard application circuit (Figure 1)
provides a single 1.1V/5A chipset supply. The
MAX17083 features a step-down switching regulator
with dual internal n-channel MOSFET power switches.
These step-down regulators use a fixed-frequency, cur-
rent-mode control scheme compensated by the output
capacitor, providing an easy-to-implement architecture
without sacrificing fast transient response. These regu-
lators also provide peak current-limit protection, and
operate pulse-skipping mode at light loads to maintain
high efficiency.
Independent enable input and open-drain power-good
output allow flexible system power sequencing. The
voltage soft-start gradually ramps up the output voltage
within a predictable time period and reduces inrush
current. The MAX17083 features outputs undervoltage,
output overvoltage, and thermal-fault protection.
Reference (REF)
The 1.25V reference is accurate to ±1% over tempera-
ture and load, making REF useful as a precision system
reference. Bypass REF to GND with a 0.1µF or greater
ceramic capacitor. The reference sources up to 50µA
and sinks 5µA to support external loads. If highly accu-
rate specifications are required for the main SMPS out-
put voltages, the reference should not be loaded.
Loading the reference slightly reduces the output volt-
age accuracy because of the reference load-regulation
error as defined in the
Electrical Characteristics table.
C1
1 μF
C3
0.1 μF
SET
EN OFF ON
V
CC 5V INPUT
L1
1 μH
OUTPUT
1.1V AT 5A
FB
GND (EP)
FREQ (OPEN)
REF
BST
LX
IN
C OUT
2x 10 μF
C
OUT
220 μF, 6mΩ
C BST
0.1 μF
R4
100k
Ω
V CC
POK
SET
FB REGULATION
VOLTAGE (V)
V
CC 1.8
OPEN 1.5
REF 1.1
GND 0.75
MAX17083
FREQ
SWITCHING
FREQUENCY (MHz)
V CC 1.5
OPEN 1.0
REF 0.75
GND 0.5
Figure 1. Standard Application Circuit