Step-Down Controllers with
Synchronous Rectifier for CPU Power
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
VL Output Current...............................................................50mA
Continuous Power Dissipation (T = +70°C)
A
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_MJE .................................................-55°C to +125°C
Storage Temperature Range.............................-65°C to +160°C
Lead Temperature (soldering, 10s) .....................................+300
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.
ELECTRICAL CHARACTERISTICS
(V+ = 15V, GND = PGND = 0V, I
= I
= 0A, T = 0°C to +70°C for MAX79_C, T = 0°C to +85°C for MAX79_E,
A A
REF
VL
T
A
= -55°C to +125°C for MAX79_M, unless otherwise noted.)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
+3.3V AND +5V STEP-DOWN CONTROLLERS
MAX79_C
MAX79_E/M
4.5
5.0
30
30
Input Supply Range
V
V
V
0mV < (CSH-CSL) < 80mV, FB = VL, 6V < V+ < 30V,
includes line and load regulation
5V Output Voltage (CSL)
3.3V Output Voltage (CSL)
4.85
3.20
5.10
3.35
5.25
3.46
0mV < (CSH-CSL) < 80mV, FB = 0V, 4.5V < V+ < 30V,
includes line and load regulation
Nominal Adjustable Output
Voltage Range
External resistor divider
REF
2.43
6
V
V
Feedback Voltage
Load Regulation
Line Regulation
(CSH-CSL) = 0V
2.505
2.5
2.57
0mV < (CSH-CSL) < 80mV
25mV < (CSH-CSL) < 80mV
6V < V+ < 30V
%
1.5
0.04
100
-100
4.0
0.06
120
-160
6.5
%/V
mV
CSH-CSL, positive
80
-50
2.5
2.0
Current-Limit Voltage
CSH-CSL, negative
SS Source Current
µA
SS Fault Sink Current
mA
FLYBACK/PWM CONTROLLER
Falling edge, hysteresis = 15mV (MAX796)
Falling edge, hysteresis = 20mV (MAX799)
2.45
2.505
0
2.55
0.05
SECFB Regulation Setpoint
V
-0.05
INTERNAL REGULATOR AND REFERENCE
VL Output Voltage
SHDN = 2V, 0mA < I < 25mA, 5.5V < V+ < 30V
4.7
3.8
4.2
5.3
4.1
4.7
V
V
V
VL
VL Fault Lockout Voltage
VL/CSL Switchover Voltage
Rising edge, hysteresis = 15mV
Rising edge, hysteresis = 25mV
2
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MAXIM [ MAXIM INTEGRATED PRODUCTS ]
