M
S tep-Down Controllers with
S ync hronous Rec tifier for CPU Power
2
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ABSOLUTE MAXIMUM RATINGS
V+ to GND.................................................................-0.3V, +36V
GND to PGND........................................................................±2V
VL to GND ...................................................................-0.3V, +7V
BST to GND...............................................................-0.3V, +36V
DH to LX...........................................................-0.3V, BST + 0.3V
LX to BST.....................................................................-7V, +0.3V
SHDN to GND............................................................-0.3V, +36V
SYNC, SS, REF, FB, SECFB, SKIP, DL to GND..-0.3V, VL + 0.3V
CSH, CSL to GND .......................................................-0.3V, +7V
VL Short Circuit to GND..............................................Momentary
REF Short Circuit to GND...........................................Continuous
ELECTRICAL CHARACTERISTICS
(V+ = 15V, GND = PGND = 0V, IVL = IREF = 0A, T
A
= 0°C to +70°C for MAX79_C, T
A
= 0°C to +85°C for MAX79_E,
T
A
= -55°C to +125°C for MAX79_M, unless otherwise noted.)
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.
VL Output Current...............................................................50mA
Continuous Power Dissipation (T
A
= +70°C)
SO (derate 8.70mW/°C above +70°C)........................696mW
Plastic DIP (derate 10.53mW/°C above +70°C) .........842mW
CERDIP (derate 10.00mW/°C above +70°C)..............800mW
Operating Temperature Ranges
MAX79_C_ _ ......................................................0°C to +70°C
MAX79_E_ _....................................................-40°C to +85°C
MAX79_MJ E .................................................-55°C to +125°C
Storage Temperature Range.............................-65°C to +160°C
Lead Temperature (soldering, 10sec) .............................+300°C
Rising edge, hysteresis = 25mV
Rising edge, hysteresis = 15mV
SHDN = 2V, 0mA < I
VL
< 25mA, 5.5V < V+ < 30V
Falling edge, hysteresis = 20mV (MAX799)
CSH-CSL, negative
CSH-CSL, positive
Falling edge, hysteresis = 15mV (MAX796)
6V < V+ < 30V
25mV < (CSH-CSL) < 80mV
0mV < (CSH-CSL) < 80mV, FB = VL, 6V < V+ < 30V,
includes line and load regulation
External resistor divider
(CSH-CSL) = 0V
0mV < (CSH-CSL) < 80mV
CONDITIONS
V
4.2
4.7
VL/CSL Switchover Voltage
V
3.8
4.1
VL Fault Lockout Voltage
V
4.7
5.3
VL Output Voltage
-0.05
0
0.05
V
2.45
2.505
2.55
SECFB Regulation Setpoint
mA
2.0
SS Fault Sink Current
FLYBACK/PWM CONTROLLER
μA
2.5
4.0
6.5
SS Source Current
5.0
30
V
4.5
30
Input Supply Range
-50
-100
-160
mV
80
100
120
Current-Limit Voltage
%/V
0.04
0.06
Line Regulation
1.5
V
4.85
5.10
5.25
5V Output Voltage (CSL)
V
REF
6
Nominal Adjustable Output
Voltage Range
V
2.43
2.505
2.5
2.57
Feedback Voltage
%
Load Regulation
UNITS
MIN
TYP
MAX
PARAMETER
MAX79_C
MAX79_E/M
0mV < (CSH-CSL) < 80mV, FB = 0V, 4.5V < V+ < 30V,
includes line and load regulation
V
3.20
3.35
3.46
3.3V Output Voltage (CSL)
+3.3V AND +5V STEP-DOWN CONTROLLERS
INTERNAL REGULATOR AND REFERENCE