数据手册MAX1843 2.7A、1MHz、内置开关降压调节器 .pdf [英文Rev.2(PDF,852kB)]

{状况:生产中。详细情况请参考订购信息。}

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.

产品关键特性
  • ±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
应用与使用范围
  • 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
典型工作电路

芯片订购型号
订购型号产品状态封装形式工作温度RoHS/无铅
MAX1843EGI限制供货MAX1843ETI+QFN;28引脚;26mm²封装信息-40°C至+85°C
MAX1843EGI-T停止供货MAX1843ETI+QFN;28引脚;26mm²封装信息-40°C至+85°C
MAX1843ETI+生产中TQFN;28引脚;26mm²封装信息-40°C至+85°C
MAX1843ETI+T生产中TQFN;28引脚;26mm²封装信息-40°C至+85°C
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典型工作电路 MAX1843