MAX1744/MAX1745
High-Voltage, Step-Down DC-DC
Controllers in µMAX
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V
IN
= V
SHDN
= 5.5V to 36V, 3/5 = GND, I
LOAD
= 0, T
A
= 0°C to +85°C, unless otherwise noted. Typical values at V
IN
= V
SHDN
=
36V, T
A
= +25°C.)
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.
IN, EXT, SHDN to GND...........................................-0.3V to +38V
VH to GND..............................................................-0.3V to +34V
VH, EXT to IN............................................................-7V to +0.3V
CS, OUT to GND ....................................................-0.3V to +20V
FB, 3/5, REF to GND .....................................-0.3V to (VL + 0.3V)
VL to GND...................................................................-0.3V to 6V
Continuous Power Dissipation (T
A
= +70°C)
10-Pin μMAX (derate 5.6mW/°C above 70°C) .............444mW
Operating Temperature Range
MAX174_EUB ..................................................-40°C to +85°C
MAX174_AUB ................................................-40°C to +125°C
Junction Temperature......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) ................................+300°C
PARAMETER CONDITIONS MIN TYP MAX UNITS
Input Voltage Range 4.5 36 V
Supply Current into IN V
SHDN
= V
IN
= 5.5V to 36V 90 140 μA
Shutdown Supply Current SHDN = GND 4 12 μA
3/5 = VL 4.85 5.00 5.15
Output Voltage (MAX1744)
3/5 = GND 3.20 3.30 3.40
V
OUT Input Current (MAX1744) 3/5 = VL, V
OUT
= 5V 28 44 μA
FB Threshold Voltage (MAX1745) Falling edge, hysteresis = 8mV 1.22 1.25 1.28 V
FB Input Current (MAX1745) -50 50 nA
VH Output Voltage with Respect to IN V
IN
= 5.5V to 36V, I
VH
= 100μA to 20mA -6.0 -5.3 -4.3 V
VL Output Voltage V
IN
= 5.5V to 36V, I
VL
= 100μA to 2mA 4.5 5.0 5.5 V
VL Undervoltage Lockout 2.0 3.0 4.1 V
V
CS
= V
OUT
= 2.5V to 18V 85 100 115
CS Threshold Voltage
V
CS
= V
OUT
= V
GND
80 110 150
mV
V
CS
= V
OUT
= 2.5V to 18V 0 15 25
CS Input Current
V
CS
= V
OUT
= V
GND
-25 0
μA
SHDN, 3/5 Logic-High Threshold V
IN
= 4.5V to 36V 2.4 V
SHDN, 3/5 Logic-Low Threshold V
IN
= 4.5V to 36V 0.4 V
3/5 Input Current SHDN = GND ±1μA
3/5 = GND ±1
SHDN Input Current
V
SHDN
= 36V 12
μA
EXT Resistance 820Ω
Minimum EXT Off-Time 1.5 2.0 2.5 μs
Minimum EXT On-Time 0.7 1.0 1.5 μs
Output Line Regulation Figure 1, 5.5V < V
IN
< 36V, I
LOAD
= 1A 5 mV/V
Output Load Regulation Figure 1, V
IN
= 12V, 30mA < I
LOAD
< 2A 15 mV/A
Reference Voltage I
REF
= 0 1.22 1.25 1.28 V
REF Load Regulation 0 ≤ I
REF
≤ 100μA 4 10 mV
REF Line Regulation V
IN
= 4.5V to 36V, I
REF
= 0 30 60 μV/V
