Storage Temperature Range...............................-65°C to +150°C
Lead Temperature (soldering, 10s)...................................+300°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.
Note 1:
Thermal properties are specified with product mounted on PC board with 1in
2
of copper area and still air.
Electrical Characteristics
(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
Input Supply Range
Input Undervoltage Lockout
Threshold
Input Supply Current
Input Supply Current in Dropout
Input Shutdown Current
SYMBOL
V
IN
V
UVLO
I
IN
I
IN(DROP)
V
IN
= 5V
SHDN
= GND
FB = GND,
I
LOAD
= 0 to 125mA
(MAX1836) or
250mA (MAX1837)
(Note 2)
MAX183_EUT50,
MAX183_ETT50
MAX183_EUT33,
MAX183_ETT33
4.80
3.168
1.25
1.200
V
OUT
= 5V
I
FB
t
OFF(MIN)
t
ON(MAX)
R
LX
I
LIM
V
FB
= 1.3V
V
IN
= 6V
MAX1836
MAX1837
250
500
-75
V
FB
= 0 or 1.25V, T
A
= +25°C
V
FB
rising or falling
-25
50
0.2
7
100
0.4
10
1.1
312
625
1.25
2.5
V
IN
rising
V
IN
falling
CONDITIONS
MIN
4.5
3.55
3.45
4.0
3.9
12
18
3
5.00
3.30
7
5.20
V
3.432
V
IN
1.300
7.4
+25
150
0.6
13
2
450
850
+75
V
V
µA
nA
mV
µs
µs
Ω
mA
mV
TYP
MAX
24
4.4
4.3
25
UNITS
V
V
µA
µA
µA
Output Voltage (Preset Mode)
V
OUT
Output Voltage Range
(Adjustable Mode)
Feedback Set Voltage
(Adjustable Mode)
OUT Bias Current
FB Bias Current
FB Dual Mode
TM
Threshold
LX Switch Minimum Off-Time
LX Switch Maximum On-Time
LX Switch On-Resistance
LX Current Limit
LX Zero-Crossing Threshold
V
OUT
V
FB
Dual Mode is a trademark of Maxim Integrated Products, Inc.
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│
2
MAX1836/MAX1837
24V Internal Switch, 100% Duty Cycle,
Step-Down Converters
Electrical Characteristics (continued)
(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
Zero-Crossing Timeout
LX Switch Leakage Current
Dropout Voltage
Line Regulation
Load Regulation
Shutdown Input Threshold
Shutdown Leakage Current
Thermal Shutdown
V
SHDN
I
SHDN
V
DROPOUT
SYMBOL
CONDITIONS
LX does not rise above the threshold
V
IN
= 18V, LX = GND, T
A
= +25°C
I
OUT
= 100mA, V
IN
= 5V
V
IN
= 5V to 24V
I
OUT
= 0 to 125mA (MAX1836) or 250mA
(MAX1837)
V
IN
= 4.5V to 24V (Note 3)
V
SHDN
= 0 or 24V
10°C hysteresis (typ)
0.8
-1
160
120
0.05
0.3
2.4
+1
MIN
TYP
30
1
MAX
UNITS
µs
µA
mV
%
%
V
µA
°C
Electrical Characteristics
(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)
PARAMETER
Input Supply Range
Input Undervoltage Lockout
Threshold
Input Supply Current
Input Shutdown Current
SYMBOL
V
IN
V
UVLO
I
IN
SHDN
= GND
FB = GND,
I
LOAD
= 0 to 125mA
(MAX1836) or
250mA (MAX1837)
(Note 2)
MAX183_EUT50,
MAX183_ETT50
MAX183_EUT33,
MAX183_ETT33
4.80
3.168
1.25
1.200
V
OUT
= 5V
V
FB
rising or falling
t
OFF(MIN)
t
ON(MAX)
R
LX
I
LIM
V
FB
= 1.3V
V
IN
= 6V
MAX1836
MAX1837
250
500
50
0.2
7
V
IN
rising
V
IN
falling
CONDITIONS
MIN
4.5
3.55
3.45
TYP
MAX
24
4.4
4.3
25
7
5.20
V
3.432
V
IN
1.300
7.4
150
0.6
13
2
450
900
V
V
µA
mV
µs
µs
Ω
mA
UNITS
V
V
µA
µA
Output Voltage (Preset Mode)
V
OUT
Output Voltage Range
(Adjustable Mode)
Feedback Set Voltage
(Adjustable Mode)
OUT Bias Current
FB Dual Mode Threshold
LX Switch Minimum Off-Time
LX Switch Maximum On-Time
LX Switch On-Resistance
LX Current Limit
V
OUT
V
FB
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│
3
MAX1836/MAX1837
24V Internal Switch, 100% Duty Cycle,
Step-Down Converters
Electrical Characteristics (continued)
(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)
PARAMETER
LX Zero-Crossing Threshold
Shutdown Input Threshold
Shutdown Leakage Current
V
SHDN
I
SHDN
V
IN
= 4.5V to 24V (Note 3)
V
SHDN
= 0 or 24V
SYMBOL
CONDITIONS
MIN
-75
0.8
-1
TYP
MAX
+75
2.4
+1
UNITS
mV
V
µA
Note 2:
When using the shutdown input, the maximum output voltage allowed with external feedback is 5.5V. If the output voltage is
set above 5.5V, connect shutdown to the input.
Note 3:
Shutdown input minimum slew rate (rising or falling) is 10V/ms.
Note 4:
Specifications to -40°C are guaranteed by design, not production tested.
Typical Operating Characteristics
(Circuits of Figures 1 (MAX1836) and 2 (MAX1837), V
IN
= 12V,
SHDN
= IN, T
A
= +25°C.)
MAX1836EUT33
OUTPUT VOLTAGE vs. LOAD CURRENT
MAX1836/7 toc01
FIGURE 1
V
IN
= 5V
3.32
OUTPUT VOLTAGE (V)
3.31
3.30
3.29
3.28
3.27
V
IN
= 9V to 12V
95
EFFICIENCY (%)
90
85
80
FIGURE 1
V
OUT
= 3.3V
V
IN
= 5V
V
IN
= 9V
MAX1836/7 toc02
FIGURE 2
3.32
OUTPUT VOLTAGE (V)
3.31
3.30
3.29
3.28
3.27
V
IN
= 9V
V
IN
= 5V
V
IN
= 12V
V
IN
= 12V
75
70
0
50
100
150
200
0.1
1
10
100
1000
0
50
100
150
200
250
300
350
LOAD CURRENT (mA)
LOAD CURRENT (mA)
LOAD CURRENT (mA)
MAX1836/7 toc05
95
EFFICIENCY (%)
90
85
80
75
70
FIGURE 2
V
OUT
= 3.3V
V
IN
= 5V
V
IN
= 9V
MAX1836/7 toc04
160
140
FREQUENCY (kHz)
120
100
80
60
40
FIGURE 2
V
OUT
= 3.3V
V
IN
= 12V
I
OUT
= 10mA
V
IN
= 9V
3.32
OUTPUT VOLTAGE (V)
3.31
3.30
3.29
3.28
3.27
FIGURE 2
V
OUT
= 3.3V
L1 = 47µH
0
4
8
12
16
20
I
OUT
= 200mA
V
IN
= 12V
0.1
1
10
100
1000
LOAD CURRENT (mA)
20
0
0
50
100
150
200
V
IN
= 5V
250
300
350
24
LOAD CURRENT (mA)
INPUT VOLTAGE (V)
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│
4
MAX1836/7 toc06
100
MAX1837EUT33
EFFICIENCY vs. LOAD CURRENT
MAX1837EUT33
SWITCHING FREQUENCY vs. LOAD CURRENT
180
3.33
MAX1837EUT33
OUTPUT VOLTAGE vs. INPUT VOLTAGE
MAX1836/7 toc03
3.33
100
MAX1836EUT33
EFFICIENCY vs. LOAD CURRENT
3.33
MAX1837EUT33
OUTPUT VOLTAGE vs. LOAD CURRENT
MAX1836/MAX1837
24V Internal Switch, 100% Duty Cycle,
Step-Down Converters
Typical Operating Characteristics (continued)
(Circuits of Figures 1 (MAX1836) and 2 (MAX1837), V