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MAX1843：2.7A、1MHz、低电压、降压型稳压器，内置同步整流，TQFN封装

2.7A、1MHz、内置开关降压调节器

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.

关键特性 ±1% Output Accuracy Up to 1MHz Switching Frequency 95% Efficiency Internal pMOS/nMOS Switches Output Voltage +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

MAX1843：典型工作电路 应用 5V或3.3V至低电压转换 芯片组供电 CPU I/O环 笔记本电脑和亚笔记本电脑

数据手册DataSheet

关键参数

质量和环境数据

• MAX1843.pdf

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