The MAX1830/MAX1831 constant-off-time, pulse-width-modulated (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 45mΩ PMOS power switch and 55mΩ NMOS synchronous-rectifier switch easily deliver continuous load currents up to 3A. The MAX1830 produces preset +2.5V, +1.8V, or +1.5V output voltage or an adjustable output from +1.1V to VIN. The MAX1831 produces preset +3.3V, +2.5V, and +1.5V output voltages and an adjustable output from +1.1V to VIN. They achieve efficiencies as high as 94%.
The MAX1830/MAX1831 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 3A, an internal digital 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 MAX1830/MAX1831 are available in 16-pin
QSOP packages.
For similar devices that provide continuous output
currents of 1A to 3A, refer to the MAX1644, MAX1623, and MAX1742/MAX1842/MAX1843 data sheets.
Key Features
Applications/Uses
±1.5% Output Accuracy
94% Efficiency
Internal PMOS/NMOS Switches
45mΩ/55mΩ On-Resistance at VIN = +4.5V
50mΩ/55mΩ On-Resistance at VIN = +3V
Output Voltages
+3.3V, +2.5V, or +1.5V Pin Selectable (MAX1831)
+2.5V, +1.8V, or +1.5V Pin Selectable (MAX1830)
+1.1V to VIN Adjustable (Both Devices)
+3V to +5.5V Input Voltage Range
750µA (max) Operating Supply Current
<1µA Shutdown Supply Current
Programmable Constant-Off-Time Operation
Up to 1MHz Switching Frequency
Idle Mode Operation at Light Loads
Thermal Shutdown
Internal Digital Soft-Start Inrush Current Limiting
Notes: **This pricing is BUDGETARY, for comparing similar parts. Prices are in
U.S. dollars and subject to change. Quantity pricing may vary
substantially and international prices may differ due to local
duties, taxes, fees, and exchange rates. For volume-specific prices
and delivery, please see the price and availability page
or contact an authorized distributor.
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