Datasheet

MAX1951A
1MHz, 2A, 2.6V to 5.5V Input, PWM DC-DC
Step-Down Regulator with Enable
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V
IN
= V
CC
= V
EN
= 3.3V, V
PGND
= V
GND
= 0V, FB in regulation, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at
T
A
= +25°C.) (Note 3)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
PARAMETER CONDITIONS MIN TYP MAX UNITS
IN AND V
CC
IN Voltage Range 2.6 5.5 V
Supply Current Switching with no load, LX floating V
IN
= 5.5V 7 10 mA
Shutdown Current EN = GND 0.1 0.4 mA
V
CC
rising 2.19 2.32
V
CC
Undervoltage Lockout
Threshold
When LX starts/stops switching
V
CC
falling 1.92 2.07
V
COMP
COMP Transconductance From FB to COMP, V
COMP
= 0.8V 40 50 80 µS
COMP Clamp Voltage, Low V
IN
= 2.6V to 5.5V, V
FB
= 0.9V 0.6 1 1.45 V
COMP Clamp Voltage, High V
IN
= 2.6V to 5.5V, V
FB
= 0.7V 1.97 2.13 2.28 V
FB
Output Voltage Range When using external feedback resistors to drive FB 0.8 V
IN
V
T
A
= 0°C to +85°C 0.789 0.796 0.804
FB Regulation Voltage
(Error Amplifier Only)
I
OUT
= 0A to 1.5A, V
IN
= 2.6V to
5.5V
T
A
= -40°C to +85°C 0.786 0.804
V
FB Input Bias Current PNP input stage -0.1 +0.1 µA
LX
V
IN
= 5V 119
V
IN
= 3.3V 145 266
LX On-Resistance, PMOS I
LX
= -180mA
V
IN
= 2.6V 171
mΩ
V
IN
= 5V 122
V
IN
= 3.3V 133 246LX On-Resistance, NMOS I
LX
= 180mA
V
IN
= 2.6V 142
mΩ
IN, V
CC
to GND ........................................................-0.3V to +6V
COMP, FB, EN to GND...............................-0.3V to (V
CC
+ 0.3V)
LX Current (Note 1).............................................................±4.5A
PGND to GND..............................................Internally connected
Continuous Power Dissipation (T
A
= +70°C)
8-Pin SO (derate 12.2mW/°C above +70°C).................976mW
Junction-to-Case Thermal Resistance (
θ
JC
) (Note 2)
8-Pin SO ........................................................................32°C/W
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature Range ............................-40°C to +150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Note 1: LX has internal clamp diodes to PGND and IN. Applications that forward bias these diodes should take care not to exceed
the IC’s package power dissipation limits.
Note 2: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-
layer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial
.