回到顶部

低噪声、双输出、稳压型电荷泵,用于GaAsFET、LCD及VCO供电

低输出纹波、可同步开关频率

产品详情

主要特征

简化框图

Technical Docs

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

主要特征

  • Dual Positive/Negative Regulated Outputs: ±5VOUT from 3VIN
  • Output-Ready Indicator to Protect GaAsFET PAs
  • 2.5V to 5.5V Input Voltage Range
  • Low-Noise Output Ripple: < 2mVp-p
  • Synchronizable Switching Frequency
  • Uses Only Small, Low-Cost Capacitors
  • 0.1µA Independent Shutdown Controls
  • Adjustable Output Voltages
  • Small 16-Pin QSOP Package

应用/用途

  • 蜂窝电话
  • GaAsFET功率放大器偏置
  • 调制解调器
  • PCS及无绳电话
  • LCD正和负电源
  • 调谐二极管电源
  • 压控振荡器(VCO)电源
  • 无线手持计算机
  • 无线手机
  • 无线PCMCIA卡

描述

The MAX768 low-noise, dual-output, regulated charge pump provides a negative output for biasing GaAsFET power amplifiers, and a positive output for powering voltage-controlled oscillators (VCOs) in wireless handsets. The outputs can also be used to power LCDs. Output ripple is less than 2mVp-p. The MAX768 is intended for use in low-voltage systems where a simple charge-pump inverter is inadequate, or where the VCO needs more range to improve its signal-to-noise ratio. The input range is 2.5V to 5.5V, enabling direct power from 1Li+ and 3-cell NiMH/NiCd batteries.

The MAX768 includes a voltage-doubler charge pump, followed by an inverting charge pump. This combination produces unregulated outputs that are ±2x the input. Two internal low-dropout linear regulators provide the low-noise, regulated positive and negative outputs. Output current is guaranteed to be at least 5mA per output. The linear regulators use CMOS devices, so the quiescent current remains independent of output loading (even in dropout), and the dropout voltage approaches zero with no load current.

The MAX768 has two preset switching frequencies (25kHz or 100kHz), or can be synchronized by an external clock from 20kHz to 240kHz. This flexibility permits users to optimize their designs based on noise, capacitor size, and quiescent-supply-current criteria.

The device features Dual Mode™ operation: the output voltage is preset to +5V and -5V, or can be adjusted by adding external resistor dividers. Other features include independent shutdowns and a logic output that signals when the negative voltage has risen to within 10% of its regulation setpoint (to protect the power amplifier GaAsFET). The MAX768 is available in a space-saving, 16-pin QSOP, which is the same size as a standard 8-pin SO.

简化框图

MAX768:典型工作电路 MAX768:典型工作电路 Zoom icon

Technical Docs

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