MAX1742EEE

MAX1742EEE Datasheet

MAX1742/MAX1842

Part	Datasheet
MAX1742EEE	MAX1742EEE (pdf)

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MAX1742/MAX1842 EVAALVUAAILTAIOBNLEKIT 1A/2.7A, 1MHz, Step-Down Regulators with Synchronous Rectification and Internal Switches The MAX1742/MAX1842 constant-off-time, pulse-widthmodulated PWM step-down DC-DC converters are ideal for use in 5V and 3.3V to low-voltage conversion necessary in notebook and subnotebook computers. These devices feature internal synchronous rectification for high efficiency and reduced component count. They require no external Schottky diode. The internal 90mΩ PMOS power switch and 70mΩ NMOS synchronous-rectifier switch easily deliver continuous load currents up to 1A. The MAX1742/MAX1842 produce a preset 2.5V, 1.8V, or 1.5V output voltage or an adjustable output from 1.1V to VIN. They achieve efficiencies as high as The MAX1742/MAX1842 use a unique current-mode, constant-off-time, PWM control scheme, which includes Idle Mode to maintain high efficiency during light-load operation. The programmable constant-off-time architecture sets switching frequencies up to 1MHz, allowing the user to optimize performance trade-offs between efficiency, output switching noise, component size, and cost. Both devices are designed for continuous output currents up to 1A. The MAX1742 uses a peak current limit of 1.3A min and is suitable for applications requiring small external component size and high efficiency. The MAX1842 has a higher current limit of 3.1A min and is intended for applications requiring an occasional burst of output current up to 2.7A. Both devices also feature an adjustable soft-start to limit surge currents during startup, a 100% duty cycle mode for low-dropout operation, and a low-power shutdown mode that disconnects the input from the output and reduces supply current below 1µA. The MAX1742/MAX1842 are available in 16pin QSOP packages. For similar devices that provide continuous output currents up to 2A and 3A, refer to the MAX1644 and MAX1623 data sheets. 5V or 3.3V to Low-Voltage Conversion CPU I/O Ring Chipset Supplies Notebook and Subnotebook Computers Pin Configuration appears at end of data sheet. Idle Mode is a trademark of Maxim Integrated Products. ±1% Output Accuracy 95% Efficiency Internal PMOS and NMOS Switches 90mΩ On-Resistance at VIN = 4.5V 110mΩ On-Resistance at VIN = 3V Output Voltage 2.5V, 1.8V, or 1.5V Pin Selectable 1.1V to VIN Adjustable 3V to 5.5V Input Voltage Range 600uA max Operating Supply Current <1uA Shutdown Supply Current Programmable Constant-Off-Time Operation 1MHz max Switching Frequency Idle-Mode Operation at Light Loads Thermal Shutdown Adjustable Soft-Start Inrush Current Limiting 100% Duty Cycle During Low-Dropout Operation Output Short-Circuit Protection 16-Pin QSOP Package Ordering Information PART MAX1742EEE TEMP RANGE -40°C to +85°C MAX1742EEE+ MAX1842EEE+ -40°C to +85°C -40°C to +85°C -40°C to +85°C + Denotes lead-free package. PIN-PACKAGE 16 QSOP 16 QSOP 16 QSOP 16 QSOP Typical Configuration INPUT 3V TO 5.5V 10Ω 2.2uF 470pF MAX1742 FB MAX1842 PGND SHDN COMP TOFF GND FBSEL OUTPUT 1.1V TO VIN 1uF 0.01uF Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at 1A/2.7A, 1MHz, Step-Down Regulators with Synchronous Rectification and Internal Switches MAX1742/MAX1842 ABSOLUTE MAXIMUM RATINGS VCC, IN to GND to +6V IN to GND to All Other Pins to VCC + 0.3V LX Current Note REF Short Circuit to GND Duration ............................Continuous ESD Protection Continuous Power Dissipation TA = +70°C SSOP derate 16.7mW/°C above +70°C part mounted on 1 in.2 of 1oz. copper ...............................1W Operating Temperature Range ...........................-40°C to +85°C Storage Temperature Range .............................-65°C to +150°C Lead Temperature soldering, 10s +300°C Note 1 LX has internal clamp diodes to PGND and IN. Applications that forward-bias these diodes should take care not to exceed the IC’s package power dissipation limits. 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. ELECTRICAL CHARACTERISTICS VIN = VCC = 3.3V, FBSEL = GND, TA = 0°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C. PARAMETER Input Voltage SYMBOL VIN, VCC CONDITIONS FBSEL = VCC TA = +25°C to +85°C TA = +0°C to +85°C Preset Output Voltage VOUT VIN = 3V to 5.5V, ILOAD = 0 to 1A for MAX1742, ILOAD = 0 to 2.5A for MAX1842, VFB = VOUT FBSEL = unconnected FBSEL = REF TA = +25°C to +85°C TA = +0°C to +85°C TA = +25°C to +85°C TA = +0°C to +85°C FBSEL = GND TA = +25°C to +85°C TA = +0°C to +85°C Adjustable Output Voltage Range AC Load Regulation Error DC Load Regulation Error Dropout Voltage Reference Voltage Reference Load Regulation PMOS Switch On-Resistance NMOS Switch On-Resistance VIN = VCC = 3V to 5.5V, ILOAD = 0, FBSEL = GND VDO VREF RON, P VIN = VCC = 3V, ILOAD = 1A TA = +25°C to +85°C TA = +0°C to +85°C IREF = -1µA to +10µA ILX = 0.5A RON, N ILX = 0.5A

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MAX1742/MAX1842

EVAALVUAAILTAIOBNLEKIT
1A/2.7A, 1MHz, Step-Down Regulators with Synchronous Rectification and Internal Switches

The MAX1742/MAX1842 constant-off-time, pulse-widthmodulated PWM step-down DC-DC converters are ideal for use in 5V and 3.3V to low-voltage conversion necessary in notebook and subnotebook computers. These devices feature internal synchronous rectification for high efficiency and reduced component count. They require no external Schottky diode. The internal 90mΩ PMOS power switch and 70mΩ NMOS synchronous-rectifier switch easily deliver continuous load currents up to 1A. The MAX1742/MAX1842 produce a preset 2.5V, 1.8V, or 1.5V output voltage or an adjustable output from 1.1V to VIN. They achieve efficiencies as high as The MAX1742/MAX1842 use a unique current-mode, constant-off-time, PWM control scheme, which includes Idle Mode to maintain high efficiency during light-load operation. The programmable constant-off-time architecture sets switching frequencies up to 1MHz, allowing the user to optimize performance trade-offs between efficiency, output switching noise, component size, and cost. Both devices are designed for continuous output currents up to 1A. The MAX1742 uses a peak current limit of 1.3A min and is suitable for applications requiring small external component size and high efficiency. The MAX1842 has a higher current limit of 3.1A min and is intended for applications requiring an occasional burst of output current up to 2.7A. Both devices also feature an adjustable soft-start to limit surge currents during startup, a 100% duty cycle mode for low-dropout operation, and a low-power shutdown mode that disconnects the input from the output and reduces supply current below 1µA. The MAX1742/MAX1842 are available in 16pin QSOP packages.

For similar devices that provide continuous output currents up to 2A and 3A, refer to the MAX1644 and MAX1623 data sheets.
5V or 3.3V to Low-Voltage Conversion

CPU I/O Ring

Chipset Supplies

Notebook and Subnotebook Computers

Pin Configuration appears at end of data sheet.

Idle Mode is a trademark of Maxim Integrated Products.
±1% Output Accuracy 95% Efficiency Internal PMOS and NMOS Switches
90mΩ On-Resistance at VIN = 4.5V 110mΩ On-Resistance at VIN = 3V Output Voltage 2.5V, 1.8V, or 1.5V Pin Selectable 1.1V to VIN Adjustable 3V to 5.5V Input Voltage Range 600uA max Operating Supply Current <1uA Shutdown Supply Current Programmable Constant-Off-Time Operation 1MHz max Switching Frequency Idle-Mode Operation at Light Loads Thermal Shutdown Adjustable Soft-Start Inrush Current Limiting 100% Duty Cycle During Low-Dropout Operation Output Short-Circuit Protection 16-Pin QSOP Package
Ordering Information

PART MAX1742EEE

TEMP RANGE -40°C to +85°C

MAX1742EEE+ MAX1842EEE+
-40°C to +85°C -40°C to +85°C -40°C to +85°C
+ Denotes lead-free package.

PIN-PACKAGE 16 QSOP 16 QSOP 16 QSOP 16 QSOP

Typical Configuration

INPUT 3V TO
5.5V 10Ω
2.2uF
470pF

MAX1742 FB

MAX1842

PGND

SHDN COMP TOFF

GND FBSEL

OUTPUT 1.1V TO VIN
1uF 0.01uF

Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at
1A/2.7A, 1MHz, Step-Down Regulators with Synchronous Rectification and Internal Switches

MAX1742/MAX1842

ABSOLUTE MAXIMUM RATINGS

VCC, IN to GND to +6V IN to GND to

All Other Pins to VCC + 0.3V LX Current Note

REF Short Circuit to GND Duration ............................Continuous

ESD Protection

Continuous Power Dissipation TA = +70°C SSOP derate 16.7mW/°C above +70°C part mounted on 1 in.2 of 1oz. copper ...............................1W

Operating Temperature Range ...........................-40°C to +85°C Storage Temperature Range .............................-65°C to +150°C Lead Temperature soldering, 10s +300°C

Note 1 LX has internal clamp diodes to PGND and IN. Applications that forward-bias these diodes should take care not to exceed
the IC’s package power dissipation limits.

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.

ELECTRICAL CHARACTERISTICS

VIN = VCC = 3.3V, FBSEL = GND, TA = 0°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.

PARAMETER Input Voltage

SYMBOL VIN, VCC

CONDITIONS

FBSEL = VCC

TA = +25°C to +85°C

TA = +0°C to +85°C

Preset Output Voltage

VOUT

VIN = 3V to 5.5V, ILOAD = 0 to 1A for MAX1742, ILOAD = 0 to 2.5A for MAX1842, VFB = VOUT

FBSEL = unconnected

FBSEL = REF

TA = +25°C to +85°C

TA = +0°C to +85°C

TA = +25°C to +85°C

TA = +0°C to +85°C

FBSEL = GND

TA = +25°C to +85°C

TA = +0°C to +85°C

Adjustable Output Voltage Range AC Load Regulation Error DC Load Regulation Error Dropout Voltage

Reference Voltage

Reference Load Regulation PMOS Switch On-Resistance NMOS Switch On-Resistance

VIN = VCC = 3V to 5.5V, ILOAD = 0, FBSEL = GND

VDO VREF RON, P

VIN = VCC = 3V, ILOAD = 1A TA = +25°C to +85°C TA = +0°C to +85°C IREF = -1µA to +10µA

ILX = 0.5A

RON, N ILX = 0.5A

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Datasheet ID: MAX1742EEE 647262