Rainbow Electronics MAX8548 User Manual
Page 2
MAX8545/MAX8546/MAX8548
Low-Cost, Wide Input Range, Step-Down
Controllers with Foldback Current Limit
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V
IN
= V
L
= V
CC
= 5V, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°C.)
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.
(All voltages referenced to GND unless otherwise noted.)
V
IN
to GND ............................................................-0.3V to +30V
V
CC
to GND .............................-0.3V, lower of 6V or (VL + 0.3V)
FB to GND ................................................................-0.3V to +6V
BST to GND ............................................................-0.3V to +36V
VL, DL, COMP to GND ..............................-0.3V to (V
CC
+ 0.3V)
BST to LX..................................................................-0.3V to +6V
DH to LX ....................................................-0.3V to (V
BST
+ 0.3V)
VL Short to GND ......................................................................5s
LX to GND ......................................................................0 to 30V
Input Current (any pin) .....................................................±50mA
Continuous Power Dissipation (T
A
= +70°C)
10-Pin µMAX (derate 5.6mW/°C above +70°C) ..........444mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
V
CC
= VL, V
IN
separate from V
CC
4.9
28.0
V
IN
Operating Range
V
IN
V
IN
= VL = V
CC
2.7
5.5
V
V
IN
Undervoltage Lockout
(UVLO) Trip Level
Rising and falling edge, hysteresis = 2%
2.35
2.50
2.66
V
V
IN
Operating Supply Current
V
FB
= 0.88V (no switching)
0.7
1.2
mA
VL Output Voltage
5.5V < V
IN
< 28V, V
CC
= VL,
1mA < I
LOAD
< 25mA
4.7
5
5.3
V
Thermal Shutdown
Rising temperature, typical
hysteresis = 10
°C (Note 1)
+160
°C
OSCILLATOR
MAX8545, MAX8546
250
300
360
Frequency
f
OSC
MAX8548
80
100
120
kHz
DH output, MAX8545, MAX8546
5
Minimum Duty Cycle
DC
MIN
MAX8548
10
%
DH output, MAX8545, MAX8546
83
86
Maximum Duty Cycle
DC
MAX
MAX8548
90
95
%
SOFT-START
MAX8545, MAX8546
6.6
Digital Ramp Period
MAX8548
10.2
ms
MAX8545, MAX8546
V
OUT
/ 64
Soft-Start Levels
MAX8548
V
OUT
/ 32
V