Datasheet

(Circuits of Figures 1 (MAX1836) and 2 (MAX1837), V
IN
= 12V, SHDN = IN, T
A
= -40°C to +85°C, unless otherwise noted.) (Note 4)
(Circuits of Figures 1 (MAX1836) and 2 (MAX1837), V
IN
= 12V, SHDN = IN, T
A
= 0°C to +85°C. Typical values are at T
A
= +25°C,
unless otherwise noted.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Zero-Crossing Timeout LX does not rise above the threshold 30 µs
LX Switch Leakage Current V
IN
= 18V, LX = GND, T
A
= +25°C 1 µA
Dropout Voltage V
DROPOUT
I
OUT
= 100mA, V
IN
= 5V 120 mV
Line Regulation V
IN
= 5V to 24V 0.05 %
Load Regulation
I
OUT
= 0 to 125mA (MAX1836) or 250mA
(MAX1837)
0.3 %
Shutdown Input Threshold V
SHDN
V
IN
= 4.5V to 24V (Note 3) 0.8 2.4 V
Shutdown Leakage Current I
SHDN
V
SHDN
= 0 or 24V -1 +1 µA
Thermal Shutdown 10°C hysteresis (typ) 160 °C
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Input Supply Range V
IN
4.5 24 V
Input Undervoltage Lockout
Threshold
V
UVLO
V
IN
rising 3.55 4.4
V
V
IN
falling 3.45 4.3
Input Supply Current I
IN
25 µA
Input Shutdown Current SHDN = GND 7 µA
Output Voltage (Preset Mode) V
OUT
FB = GND,
I
LOAD
= 0 to 125mA
(MAX1836) or
250mA (MAX1837)
MAX183_EUT50,
MAX183_ETT50
4.80 5.20
V
MAX183_EUT33,
MAX183_ETT33
3.168 3.432
Output Voltage Range
(Adjustable Mode)
V
OUT
(Note 2) 1.25 V
IN
V
Feedback Set Voltage
(Adjustable Mode)
V
FB
1.200 1.300 V
OUT Bias Current V
OUT
= 5V 7.4 µA
FB Dual Mode Threshold V
FB
rising or falling 50 150 mV
LX Switch Minimum Off-Time t
OFF(MIN)
0.2 0.6 µs
LX Switch Maximum On-Time t
ON(MAX)
V
FB
= 1.3V 7 13 µs
LX Switch On-Resistance R
LX
V
IN
= 6V 2 Ω
LX Current Limit I
LIM
MAX1836 250 450
mA
MAX1837 500 900
MAX1836/MAX1837 24V Internal Switch, 100% Duty Cycle,
Step-Down Converters
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Electrical Characteristics
Electrical Characteristics (continued)