Rainbow Electronics MAX1845 - Manual (Page 2)

MAX1845
Dual, High-Efficiency, Step-Down
Controller with Accurate Current Limit
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
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.
V+ to GND ................................................................-0.3 to +30V
V
CC , V DD to GND .....................................................-0.3V to +6V
PGOOD, OUT_ to GND ............................................-0.3V to +6V
OVP, UVP, ILIM_, FB_, REF,
SKIP, TON, ON_ to GND ........................-0.3V to (V
CC + 0.3V)
DL_ to GND ................................................-0.3V to (V
DD
+ 0.3V)
BST_ to GND ..........................................................-0.3V to +36V
CS_ to GND ...............................................................-6V to +30V
DH1 to LX1 ..............................................-0.3V to (V
BST1 + 0.3V)
LX_ to BST_ ..............................................................-6V to +0.3V
DH2 to LX2 ..............................................-0.3V to (V
BST2 + 0.3V)
REF Short Circuit to GND ...........................................Continuous
Continuous Power Dissipation (T
A = +70°C)
28-Pin QSOP (derate 10.8mW/°C above +70°C)........860mW
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
ELECTRICAL CHARACTERISTICS
(Circuit of Figure 1, V DD = V CC = 5V, SKIP = GND, V+ = 15V, T A = 0°C to +85°C, typical values are at +25°C, unless otherwise
noted.) (Note 1)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
PWM CONTROLLERS
V+ Battery voltage, V+ 2 28
Input Voltage Range
V CC /V DD V CC , V DD 4.5 5.5
V
FB1 to GND 1.782 1.8 1.818
FB1 to V CC 1.485 1.5 1.515
V+ = 2V to 28V, I LOAD
= 0 to 8A, SKIP = V CC ,
+25°C to +85°C
FB1 to OUT1 0.99 1 1.01
FB1 to GND 1.773 1.8 1.827
FB1 to V CC 1.477 1.5 1.523
DC Output Voltage OUT1
(Note 2)
V OUT1
V+ = 2V to 28V, I LOAD
= 0 to 8A, SKIP = V CC ,
0°C to +85°C
FB1 to OUT1 0.985 1 1.015
V
FB2 to GND 2.475 2.5 2.525
V+ = 4.5V to 28V,
I
LOAD
= 0 to 4A,
SKIP = V
CC ,
+25°C to +85°C
FB2 to OUT2 0.99 1 1.01
FB2 to GND 2.463 2.5 2.537
DC Output Voltage OUT2
(Note 2)
V OUT2
V+ = 4.5V to 28V,
I
LOAD
= 0 to 4A,
SKIP = V
CC ,
0°C to +85°C
FB2 to OUT2 0.985 1 1.015
V
Output Voltage Adjust Range OUT1, OUT2 1 5.5 V
Dual-Mode Threshold, Low OVP, FB_ 0.05 0.1 0.15 V
OVP, ILIM_
V CC -
1.5
V CC -
0.4 Dual-Mode Threshold, High
FB1 1.9 2.0 2.1
V
R OUT1 V OUT1 = 1.5V 75
OUT_ Input Resistance
R OUT2 V OUT2 = 2.5V 100
k Ω
FB_ Input Bias Current I FB -0.1 0.1 µA
Soft-Start Ramp Time Zero to full ILIM 1700 µs
TON = GND 120 137 153
TON = REF 153 174 195
TON = float 222 247 272
On-Time, Side 1 (Note 3) t ON1
V+ = 24V,
V
OUT1 = 2V
TON = V CC 316 353 390
ns