MAX797H
High-Voltage, Step-Down Controller with
Synchronous Rectifier for CPU Power
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V+ = 15V, GND = PGND = 0V, I
VL
= I
REF
= 0A, T
A
= 0°C to +85°C, SYNC = 0V, unless otherwise noted.)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress rating s only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specificatio ns is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
V+ to GND ................................................................-0.3V to 36V
GND to PGND........................................................................±2V
VL to GND...................................................................-0.3V to 7V
BST to GND ..............................................................-0.3V to 46V
DH to LX .....................................................-0.3V to (BST + 0.3V)
LX to BST ....................................................................-7V to 0.3V
SHDN to GND ...........................................................-0.3V to 36V
SYNC, SS, REF, FB, SKIP, DL to GND ...........-0.3V to (VL + 0.3V)
CSH, CSL to GND.......................................................-0.3V to 7V
VL Short Circuit to GND..............................................Momentary
REF Short Circuit to GND ...........................................Continuous
VL Output Current ...............................................................50mA
Continuous Power Dissipation (T
A
= +70°C)
SO (derate 8.70mW/°C above +70°C)........................696mW
Operating Temperature Range
MAX797HESE .................................................-40°C to +85°C
Storage Temperature Range .............................-65°C to +160°C
Lead Temperature (soldering, 10sec) .............................+300°C
Rising edge, hysteresis = 25mV
V+
Rising edge, hysteresis = 15mV
SHDN = 2V, 0mA < I
VL
< 25mA, 5.5V < V+ < 30V
CSH - CSL, negative
CSH - CSL, positive
FB = VL, 6V < power input < 40V (Note 4)
25mV < (CSH - CSL) < 80mV
0mV < (CSH - CSL) < 80mV, FB = VL,
6V < power input < 40V, includes line and load
regulation (Note 4)
External resistor divider
CSH - CSL = 0V
0mV < (CSH - CSL) < 80mV
CONDITIONS
V4.2 4.7VL/CSL Switchover Voltage
V3.8 4.1VL Fault Lockout Voltage
V4.7 5.3VL Output Voltage
mA2.0SS Fault Sink Current
µA2.5 4.0 6.5SS Source Current
40
V
4.5 30
Input Supply Range
-50 -100 -160
mV
80 100 120
Current-Limit Voltage
1.5
V4.85 5.10 5.255V Output Voltage (CSL)
VREF 6
Nominal Adjustable Output
Voltage Range
V2.43 2.505 2.57Feedback Voltage
%
2.5
Load Regulation
UNITSMIN TYP MAXPARAMETER
High-side MOSFET drain
0mV < (CSH - CSL) < 80mV, FB = 0V,
4.5V < power input < 40V, includes line and load
regulation (Note 4)
V3.20 3.35 3.463.3V Output Voltage (CSL)
FB = 0V, 4.5V < power input < 40V (Note 4)
%/V
0.04 0.06
Line Regulation
+3.3V AND +5V STEP-DOWN CONTROLLERS
FLYBACK/PWM CONTROLLERINTERNAL REGULATOR AND REFERENCE
0.04 0.06
