MAX1842EEE Maxim Integrated Products, MAX1842EEE Datasheet - Page 10

• Manufacturer Part Number: MAX1842EEE
• Description: DC/DC Switching Regulators
• Manufacturer: Maxim Integrated Products

Specifications of MAX1842EEE

• Case: ssop
• Dc: 02+
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

1A/2.7A, 1MHz, Step-Down Regulators with
Synchronous Rectification and Internal Switches
Figure 1. Typical Circuit
Figure 2. Functional Diagram
In a step-down regulator without synchronous rectifica-
tion, an external Schottky diode provides a path for cur-
rent to flow when the inductor is discharging. Replacing
the Schottky diode with a low-resistance NMOS syn-
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V
IN
NOTE: HEAVY LINES DENOTE HIGH-CURRENT PATHS.
10Ω
470pF
2.2μF
1μF
Synchronous Rectification
COMP
SHDN
REF
V
CC
2.2μF
INPUT
C
C
IN
IN
REF
= 10μF (MAX1742)
= 33μF (MAX1842)
10Ω
470pF
R
G
TOFF
m
REF
GND
REF
SELECTION
FEEDBACK
SHDN
COMP
TOFF
IN
V
CC
FBSEL
MAX1742
FBSEL
PGND
GND
REF
SS
LX
FB
COMPARATOR
MAX1742
MAX1842
SUMMING
TIMER
chronous switch reduces conduction losses and
improves efficiency.
The NMOS synchronous-rectifier switch turns on follow-
ing a short delay after the PMOS power switch turns off,
thus preventing cross conduction or “shoot through.” In
TOFF
R
TOFF
L
0.01μF
1μF
PWM LOGIC
CURRENT
CURRENT
DRIVERS
SS
SENSE
SENSE
AND
SKIP
V
V
V
OUT
OUT
OUT
= 2.5V, FBSEL = V
= 1.8V, FBSEL = REF
= 1.5V, FBSEL = FLOATING
OUTPUT
C
C
OUT
OUT
0.01μF
PGND
= 47μF (MAX1742)
= 150μF (MAX1842)
CC
LX
FB
IN
10μF
C
V
3.0V TO 5.5V
IN
OUT
V
OUT