MAX1843
PRODUCTION2.7A, 1MHz, Low-Voltage, Step-Down Regulator with Internal Synchronous Rectification in TQFN Package
2.7A, 1MHz, Internal Switch Step Down Regulator
- Part Models
- 2
- 1ku List Price
- Starting From $6.69
Overview
- ±1% Output Accuracy
- Up to 1MHz Switching Frequency
- 95% Efficiency
- Internal pMOS/nMOS Switches
- 90mΩ/70mΩ On-Resistance at VIN = +4.5V
- 110mΩ/80mΩ 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
- 350µA Operating Supply Current
- < 1µA Shutdown Supply Current
- Programmable Constant-Off-Time Operation
- 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
- 28-Pin TQFN Package
The MAX1843 constant-off-time, pulse-width modulated (PWM) step-down DC-DC converter is ideal for use in 5V and 3.3V to low-voltage conversion necessary in notebook and subnotebook computers. This device features an internal PMOS power switch and internal synchronous rectification for high efficiency and reduced component count. An external Schottky diode is not required. The internal 90mΩ power switch and 70mΩ nMOS synchronous-rectifier switch easily deliver continuous load currents up to 2.7A. The MAX1843 produces a preset +2.5V, +1.8V, or +1.5V output voltage or an adjustable output from +1.1V to VIN. It achieves efficiencies as high as 95%.
The MAX1843 uses 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. The MAX1843 features 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 MAX1843 is available in a 28-pin TQFN package with an exposed backside pad.
Applications
- 5V or 3.3V to Low-Voltage Conversion
- Chipset Supplies
- CPU I/O Ring
- Notebook and Subnotebook Computers
Documentation
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal. View our quality and reliability program and certifications for more information.
| Part Model | Pin/Package Drawing | Documentation | CAD Symbols, Footprints, and 3D Models |
|---|---|---|---|
| MAX1843ETI+ | LFCSP | ||
| MAX1843ETI+T | LFCSP |
This is the most up-to-date revision of the Data Sheet.
Software Resources
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| Parts | Product Life Cycle | Description |
|---|---|---|
| Switching Regulators & Controllers 4 | ||
| MAX1644 | PRODUCTION | 2A, Low-Voltage, Step-Down Regulator with Synchronous Rectification and Internal Switches |
| MAX1623 | PRODUCTION | 3A, Low-Voltage, Step-Down Regulator with Synchronous Rectification and Internal Switches |
| MAX1742 | PRODUCTION | 1A/2.7A, 1MHz, Step-Down Regulators with Synchronous Rectification and Internal Switches |
| MAX1842 | PRODUCTION | 1A/2.7A, 1MHz, Step-Down Regulators with Synchronous Rectification and Internal Switches |
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