MAX1742
1A/2.7A, 1MHz, Step-Down Regulators with Synchronous Rectification and Internal Switches
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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 16-pin QSOP packages.
For similar devices that provide continuous output currents up to 2A and 3A, refer to the MAX1644 and MAX1623 data sheets.
Key Features
- ±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
- 600µA (max) Operating Supply Current
- <1µA 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
Applications/Uses
- 5V or 3.3V to Low-Voltage Conversion
- Chipset Supplies
- CPU I/O Ring
- Notebook and Subnotebook Computers
| VIN (V) (min) | 3 |
| VIN (V) (max) | 5.5 |
| VOUT1 (V) (min) | 1.1 |
| VOUT1 (V) (max) | 5.5 |
| IOUT1 (A) (max) | 1 |
| Switch Type | Internal |
| Preset VOUT (V) | 1.5 1.8 2.5 |
| Output Adjust. Method | Preset Resistor |
| Synchronous Switching? | Yes |
| # DC-DC Outputs | 1 |
| Switching Frequency (kHz) | 1000 |
| Package/Pins | QSOP/16 |
| Budgetary Price (See Notes) | $4.42 @1k |
Technical Docs
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Description
The MAX1742 and MAX1842 evaluation kits (EV kits) provide a +1.8V adjustable output voltage from a +3V to +5.5V input source. The MAX1742 delivers up to 1A of output current, and the MAX1842 delivers up to 2.5A of output current.
The MAX1742/MAX1842 are step-down switching regulators with internal synchronous-rectifiers that operate up to 1MHz, which minimizes external components. The devices feature resistor-programmable, fixed off-time current-mode operation for superior load- and line-transient response, and achieve efficiencies up to 95%.
The MAX1742/MAX1842 EV kits can also be used to evaluate other output voltages by adding feedback resistors R1 and R2 or by using the jumper-selectable +1.1V, +1.5V, +1.8V, or +2.5V settings.
Features
- 1A Output Current for MAX1742
2.5A Output Current for MAX1842 - Up to 1MHz Switching Frequency
- Up to 95% Efficiency
- Synchronous Rectification for Improved Efficiency
- No External Schottky Diode Required
- Output Voltage
- +1.1V, +1.5V, +1.8V, or +2.5V Selectable
- +1.1V to VIN Adjustable
- +3V to +5.5V Input Voltage Range
- < 1µA (typ) IC Shutdown Current
- Surface-Mount Construction
- Fully Assembled and Tested
Description
The MAX1742 and MAX1842 evaluation kits (EV kits) provide a +1.8V adjustable output voltage from a +3V to +5.5V input source. The MAX1742 delivers up to 1A of output current, and the MAX1842 delivers up to 2.5A of output current.
The MAX1742/MAX1842 are step-down switching regulators with internal synchronous-rectifiers that operate up to 1MHz, which minimizes external components. The devices feature resistor-programmable, fixed off-time current-mode operation for superior load- and line-transient response, and achieve efficiencies up to 95%.
The MAX1742/MAX1842 EV kits can also be used to evaluate other output voltages by adding feedback resistors R1 and R2 or by using the jumper-selectable +1.1V, +1.5V, +1.8V, or +2.5V settings.
Features
- 1A Output Current for MAX1742
2.5A Output Current for MAX1842 - Up to 1MHz Switching Frequency
- Up to 95% Efficiency
- Synchronous Rectification for Improved Efficiency
- No External Schottky Diode Required
- Output Voltage
- +1.1V, +1.5V, +1.8V, or +2.5V Selectable
- +1.1V to VIN Adjustable
- +3V to +5.5V Input Voltage Range
- < 1µA (typ) IC Shutdown Current
- Surface-Mount Construction
- Fully Assembled and Tested
Support & Training
Search our knowledge base for answers to your technical questions.
Filtered SearchOur dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal
Parameters
| VIN (V) (min) | 3 |
| VIN (V) (max) | 5.5 |
| VOUT1 (V) (min) | 1.1 |
| VOUT1 (V) (max) | 5.5 |
| IOUT1 (A) (max) | 1 |
| Switch Type | Internal |
| Preset VOUT (V) | 1.5 1.8 2.5 |
| Output Adjust. Method | Preset Resistor |
| Synchronous Switching? | Yes |
| # DC-DC Outputs | 1 |
| Switching Frequency (kHz) | 1000 |
| Package/Pins | QSOP/16 |
| Budgetary Price (See Notes) | $4.42 @1k |
Key Features
- ±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
- 600µA (max) Operating Supply Current
- <1µA 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
Applications/Uses
- 5V or 3.3V to Low-Voltage Conversion
- Chipset Supplies
- CPU I/O Ring
- Notebook and Subnotebook Computers
Description
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 16-pin QSOP packages.
For similar devices that provide continuous output currents up to 2A and 3A, refer to the MAX1644 and MAX1623 data sheets.
Technical Docs
Support & Training
Search our knowledge base for answers to your technical questions.
Filtered SearchOur dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal
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