MAX1837EUT33-T ,24V Internal Switch / 100% Duty Cycle / Step-Down ConvertersFeaturesThe MAX1836/MAX1837 high-efficiency step-down 4.5V to 24V Input Voltage Rangeconverters pr ..
MAX1838EEE ,Dual USB Switch with Fault Blanking and AutoresetELECTRICAL CHARACTERISTICS(V = V = 5V, ON = SEL = GND, ADJ_ = open, T = 0°C to +85°C, unless otherw ..
MAX1838EEE ,Dual USB Switch with Fault Blanking and AutoresetApplicationsDesktopsTypical Operating CircuitNotebook ComputersUSB PortsDocking StationsPin Configu ..
MAX1839EEP ,Wide Brightness Range CCFL Backlight ControllersApplicationsNotebook/Laptop ComputersTOP VIEWCar Navigation DisplaysREF 1 20 BATTLCD MonitorsMINDAC ..
MAX183BCNG ,High-Speed 12-Bit A/D Converters With External Refernce inputGeneral Description
The MAX183/184/185 are 12-bit, high-speed,
BiCMOS, analog-to-digital conver ..
MAX183BCNG+ ,3µs, 12-Bit ADCFeatures
. 12-Blt Resolutlon and Accuracy
. Fast Conversion Tlmes:
MAX183 - 3ps
MAX184 - 5 ..
MAX4723EUA+ ,4.5Ω Dual SPST Analog Switches in UCSPMAX4721/MAX4722/MAX472319-2632; Rev 0; 10/024.5Ω Dual SPST Analog Switches in UCSP
MAX4729EXT+T ,Low-Voltage 3.5Ω, SPDT, CMOS Analog SwitchesApplicationsBattery-Operated EquipmentAudio and Video-Signal RoutingLow-Voltage Data-Acquisition Sy ..
MAX472CSA ,Precision, High-Side Current-Sense AmplifiersMAX471/MAX47219-0335; Rev 2; 12/96Precision, High-Side Current-Sense Amplifiers_______________
MAX472CSA+ ,Precision, High-Side Current-Sense AmplifiersFeaturesThe MAX471/MAX472 are complete, bidirectional, high-♦ Complete High-Side Current Sensingsid ..
MAX472ESA ,Precision, High-Side Current-Sense AmplifiersFeaturesThe MAX471/MAX472 are complete, bidirectional, high-' Complete High-Side Current Sensingsid ..
MAX472ESA-T ,Precision, High-Side Current-Sense AmplifiersApplicationsMAX471CSA 0°C to +70°C 8 SOPortable PCs:MAX471EPA -40°C to +85°C 8 Plastic DIPNotebooks ..
MAX1836EUT33-MAX1836EUT33-T-MAX1836EUT50-T-MAX1837EUT33-MAX1837EUT33/T-MAX1837EUT33-T
24V Internal Switch / 100% Duty Cycle / Step-Down Converters
General DescriptionThe MAX1836/MAX1837 high-efficiency step-down
converters provide a preset 3.3V or 5V output voltage
from supply voltages as high as 24V. Using external
feedback resistors, the output voltage may be adjusted
from 1.25V to VIN. An internal current-limited switching
MOSFET delivers load currents up to 125mA
(MAX1836) or 250mA (MAX1837).
The unique current-limited control scheme, operating
with duty cycles up to 100%, minimizes the dropout
voltage (120mV at 100mA). Additionally, this control
scheme reduces supply current under light loads to
12µA. High switching frequencies allow the use of tiny
surface-mount inductors and output capacitors.
The MAX1836/MAX1837 step-down converters with
internal switching MOSFETs are available in a 6-pin
SOT23 package, making them ideal for low-cost, low-
power, space-sensitive applications. For increased out-
put drive capability, use the MAX1776 step-down
converter that uses an internal 24V switch to deliver up
to 500mA. For even higher currents, use the MAX1626/
MAX1627 step-down controllers that drive an external
P-channel MOSFET to deliver up to 20W.
________________________Applications9V Battery Systems
Notebook Computers
Distributed Power Systems
Backup Supplies
4mA to 20mA Loop Power Supplies
Industrial Control Supplies
Hand-Held Devices
____________________________Features4.5V to 24V Input Voltage RangePreset 3.3V or 5V OutputAdjustable Output from 1.25V to VINOutput Currents Up to 125mA (MAX1836) or
250mA (MAX1837)Internal P-Channel MOSFETEfficiency Over 90%12µA Quiescent Current3µA Shutdown Current100% Maximum Duty Cycle for Low DropoutCurrent-Limiting and Overtemperature ProtectionSmall 6-Pin SOT23 Package
MAX1836/MAX1837
24V Internal Switch, 100% Duty Cycle,
Step-Down Converters19-1919; Rev 1; 01/02
Selector Guide
Typical Operating Circuit
Pin Configuration
Note:The MAX1836/MAX1837 require special solder tempera-
ture profile described in the Absolute Maximum Ratings.
Ordering Information
MAX1836/MAX1837
24V Internal Switch, 100% Duty Cycle,
Step-Down Converters
ABSOLUTE MAXIMUM RATINGSStresses 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, SHDNto GND...................................................-0.3V to +25V
LX to GND.......................................................-2V to (VIN+ 0.3V)
OUT, FB to GND.......................................................-0.3V to +6V
Continuous Power Dissipation (TA= +70°C) (Note 1)
6-Pin SOT23 (derate 8.7mW/°C above +70°C)............696mW
Operating Temperature Range...........................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10s).................................+300°C
Note 1:Thermal properties are specified with product mounted on PC board with 1in2of copper area and still air.
ELECTRICAL CHARACTERISTICS(Circuits of Figures 1 (MAX1836) and 2 (MAX1837), VIN= 12V, SHDN= IN, TA
= 0°C to +85°C. Typical values are at TA= +25°C,
unless otherwise noted.)
Dual Mode is a trademark of Maxim Integrated Products, Inc.
MAX1836/MAX1837
24V Internal Switch, 100% Duty Cycle,
Step-Down Converters
ELECTRICAL CHARACTERISTICS (continued)(Circuits of Figures 1 (MAX1836) and 2 (MAX1837), VIN= 12V, SHDN= IN, TA
= 0°C to +85°C. Typical values are at TA= +25°C,
unless otherwise noted.)
ELECTRICAL CHARACTERISTICS
MAX1836/MAX1837
Typical Operating Characteristics(Circuits of Figures 1 (MAX1836) and 2 (MAX1837), VIN= 12V, SHDN= IN, TA = +25°C.)
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.
ELECTRICAL CHARACTERISTICS (continued)
MAX1836/MAX1837
24V Internal Switch, 100% Duty Cycle,
Step-Down ConvertersMAX1837EUT33
EFFICIENCY vs. INPUT VOLTAGE
MAX1836/7 toc07
INPUT VOLTAGE (V)
EFFICIENCY (%)
INPUT VOLTAGE (V)
FREQUENCY (kHz)
MAX1837EUT33
SWITCHING FREQUENCY vs. INPUT VOLTAGE2420
MAX1836/7 toc08
MAX1837EUT33
PEAK INDUCTOR CURRENT vs. INPUT VOLTAGE
MAX1836/7 toc09
INPUT VOLTAGE (V)
PEAK INDUCTOR CURRENT (mA)
MAX1837EUT50
OUTPUT VOLTAGE vs. LOAD CURRENT
MAX1836/7 toc10
LOAD CURRENT (mA)
OUTPUT VOLTAGE (V)
MAX1837EUT50
EFFICIENCY vs. LOAD CURRENT
MAX1836/7 toc11
LOAD CURRENT (mA)
EFFICIENCY (%)
MAX1837EUT50
DROPOUT VOLTAGE vs. LOAD CURRENT
MAX1836/7 toc12
LOAD CURRENT (mA)
DROPOUT VOLTAGE (mV)
NO-LOAD SUPPLY CURRENT
vs. INPUT VOLTAGE
MAX1836/7 toc13
INPUT VOLTAGE (V)
SUPPLY CURRENT (
Typical Operating Characteristics (continued)(Circuits of Figures 1 (MAX1836) and 2 (MAX1837), VIN= 12V, SHDN= IN, TA = +25°C.)
MAX1836/MAX1837
24V Internal Switch, 100% Duty Cycle,
Step-Down Converters
Typical Operating Characteristics (continued)(Circuits of Figures 1 (MAX1836) and 2 (MAX1837), VIN= 12V, SHDN= IN, TA = +25°C.)
MAX1836/MAX1837
24V Internal Switch, 100% Duty Cycle,
Step-Down Converters
Detailed DescriptionThe MAX1836/MAX1837 step-down converters are
designed primarily for battery-powered devices, note-
book computers, and industrial control applications. A
unique current-limited control scheme provides high
efficiency over a wide load range. Operation up to
100% duty cycle allows the lowest possible dropout
voltage, increasing the useable supply voltage range.
Under no-load, the MAX1836/MAX1837 draw only
12µA, and in shutdown mode, they draw only 3µA to
further reduce power consumption and extend battery
life. Additionally, an internal 24V switching MOSFET,
internal current sensing, and a high switching frequen-
cy minimize PC board space and component cost.
Current-Limited Control ArchitectureThe MAX1836/MAX1837 use a proprietary current-limit-
ed control scheme that operates with duty cycles up to
100%. These DC-DC converters pulse as needed to
maintain regulation, resulting in a variable switching fre-
quency that increases with the load. This eliminates the
high supply currents associated with conventional con-
