Datasheet

MAX8855/MAX8855A
Dual, 5A, 2MHz Step-Down Regulators
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Figure 1. Functional Diagram
V
DD
PGND1
LX1
IN1
VDL
BST1
EN1
EN2
SS2
REFIN
FB1
COMP1
SS1
SHUTDOWN
CONTROL
UVLO
CIRCUITRY
CURRENT-LIMIT
COMPARATOR
DC
DC
ILIM
THRESHOLD
ILIM
THRESHOLD
BST CAP
CHARGING
SWITCH
V
DD
BIAS
GENERATOR
VOLTAGE
REFERENCE
REF
FROM SS2 (0.6V)
SOFT-START 1
ERROR
AMPLIFIER
PWM
COMPARATOR
SOFT-START 2
VDL
+
-
FB2
ERROR
AMPLIFIER
+
-
-
+
+-
-
+
PWM
COMPARATOR
SHDN
-
+
COMP LOW
DETECTOR
COMP2
COMP LOW
DETECTOR
IN1IN2
CONTROL
LOGIC
CLOCK
THERMAL
SHUTDOWN1
EN1
LX1
IN1
PGND2
FSYNC
LX2
IN2
BST2
CURRENT-LIMIT
COMPARATOR
BST CAP
CHARGING
SWITCH
+-
-
+
+
-
CONTROL
LOGIC
CLOCK
THERMAL
SHUTDOWN2
EN2
PWRGD1
LX2
IN2
OSCILLATOR
GND
CLOCK
+
-
FB1
0.9 x V
REFIN
REFIN
REF
540mV
SHDN
+
-
PWRGD2
+
-
FB2
0.9 x V
SS2
SS2
540mV
THERMAL
SHUTDOWN
THERMAL
SHUTDOWN2
THERMAL
SHUTDOWN1
MAX8855/MAX8855A