Datasheet

MAX1858
Dual 180° Out-of-Phase PWM Step-Down
Controller with Power Sequencing and POR
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 ..............................................................-0.3V to +25V
PGND to GND .......................................................-0.3V to +0.3V
V
L
to GND ..................-0.3V to the lower of +6V and (V+ + 0.3V)
BST1, BST2 to GND ...............................................-0.3V to +30V
LX1 to BST1..............................................................-6V to +0.3V
LX2 to BST2..............................................................-6V to +0.3V
DH1 to LX1 ..............................................-0.3V to (V
BST1
+ 0.3V)
DH2 to LX2 ..............................................-0.3V to (V
BST2
+ 0.3V)
DL1, DL2 to PGND........................................-0.3V to (V
L
+ 0.3V)
CKO, REF, OSC, ILIM1, ILIM2,
COMP1, COMP2 to GND ..........................-0.3V to (V
L
+ 0.3V)
FB1, FB2,
RST, SYNC, EN to GND...........................-0.3V to +6V
V
L
to GND Short Circuit..............................................Continuous
REF to GND Short Circuit ...........................................Continuous
Continuous Power Dissipation (T
A
= +70°C)
24-Pin QSOP (derate 9.4mW/°C above +70°C)...........762mW
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
(V+ = 12V, EN = ILIM_ = V
L
, SYNC = GND, I
VL
= 0mA, PGND = GND, C
REF
= 0.22µF, C
VL
= 4.7µF (ceramic), R
OSC
= 60kΩ,
compensation components for COMP_ are from Figure 1, T
A
= -40°C to +85°C (Note 1), unless otherwise noted.)
PARAMETER CONDITIONS
MIN
TYP
MAX
UNITS
GENERAL
(Note 2)
4.75
23
V+ Operating Range
V
L
= V+ (Note 2)
4.75
5.5
V
V+ Operating Supply Current V
L
unloaded, no MOSFETs connected 3.5 6 mA
V+ Standby Supply Current EN = LX_ = FB_ = 0V R
OSC
= 60kΩ 0.3 0.6 mA
Thermal Shutdown Rising temperature, typical hysteresis = 10°C
160
°C
ILIM_ = V
L
75
100
125
R
ILIM_
= 100kΩ 32 50 62
Current-Limit Threshold PGND - LX_
R
ILIM_
= 600kΩ
225 300
375
mV
V
L
REGULATOR
Output Voltage 5.5V < V+ < 23V, 1mA < I
LOAD
< 50mA
4.75
5
5.25
V
V
L
Undervoltage Lockout
Trip Level
4.4
4.55
4.7 V
REFERENCE
Output Voltage I
REF
= 0µA
1.98 2.00 2.02
V
Reference Load Regulation 0µA < I
REF
< 50µA 0 4 10 mV
SOFT-START
Digital Ramp Period
Internal 6-bit DAC for one converter to ramp from 0V to
full scale (Note 3)
1024
DC-DC
Clocks
Soft-Start Steps 64
Steps
FREQUENCY
0°C to +85°C 84
100
115
Low End of Range R
OSC
= 60kΩ
-40°C to +85°C 80
100
120
kHz
High End of Range R
OSC
= 10kΩ
540 600
660 kHz
DH_ Minimum Off-Time R
OSC
= 10kΩ
250
303 ns