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3.3V/5V掌上电脑及LCD电源稳压器

电池或墙上适配器供电系统,为逻辑电路及LCD供电

产品详情

主要特征

简化框图

Technical Docs

数据资料 3.3V/5V掌上电脑及LCD电源稳压器 Jun 01, 1992

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主要特征

  • Low 0.9V to 5.5V Battery Input Range
  • Unregulated 7V to 20V DC Input Range
  • Dual Regulated Outputs
    • Main Output: 3.3V/5V
    • Auxiliary Output: 0V to -100V
  • 87% Efficiency at 200mA
  • Efficient PRAM Keep-Alive: 80% at 1mA
  • 8W/in³ Power Density
  • 60µA Quiescent Current
  • 20µA Shutdown Mode with VREF Alive
  • 500kHz Maximum Switching Frequency
  • ±1.5% VREF Tolerance (Over Temp.)
  • Detect Output Power Failures
  • 16-Pin Narrow SO Packages

应用/用途

  • 条码扫描仪
  • LCD对比度调节
  • 医疗仪表
  • 掌上电脑
  • 便携式数据通信
  • 便携式数据收集设备

描述

The MAX722 and MAX723 CMOS power-supply ICs create dual regulated DC outputs for small, battery-operated microprocessor systems. Each device generates a main output (3V or 5V, selectable) and a negative auxiliary output that is adjustable for LCDs. Each device accepts two input voltages. Power can come from a main battery (two or three alkaline or NiCAD), or an unregulated DC source such as an AC-DC wall adapter.

The MAX722/MAX723 provide three improvements over prior-art devices. Physical size is reduced; the high switching frequencies (up to 0.5MHz), made possible by MOSFET power transistors, allow for tiny (< 5mm diameter) surface-mount magnetics. Efficiency is also improved to 87% (10% better than with low-voltage regulators made in bipolar technology). And supply current is reduced to 60µA by CMOS construction and a unique constant-off-time pulse-frequency modulation (PFM) control scheme.

The MAX722 and MAX723 differ only in the lower fixed output voltage of the main regulator, with a 3.3V output for the MAX722 and a 3.0V output for the MAX723.

For flash memory or PCMCIA applications that require a +12V output voltage, refer to the MAX717–721 data sheet.

简化框图

Technical Docs

数据资料 3.3V/5V掌上电脑及LCD电源稳压器 Jun 01, 1992

支持和培训

在Maxim的知识库中搜索技术问题的答案

过滤搜索

Maxim的专业工程师团队也会为您解答相应的技术问题,请访问Maxim的 支持中心