MAX687中文资料高精度、低压差线性稳压器数据手册ADI规格书

描述 Description

The MAX687/MAX688/MAX689 low-dropout linear regulators operate with an input-to-output voltage differential limited only by an external PNP transistor. Outputs are fixed at 3.3V (MAX687/MAX688) or 3.0V (MAX689). The only external components required are a PNP pass transistor and output, compensation, and bypass capacitors. Base drive to the external transistor is at least 10mA, permitting output currents to exceed 1A when using high-gain transistors (β > 100). Output current limiting is implemented by limiting the external transistor's base current. Output voltage monitoring and shutdown functions are included.
The 3.3V MAX687 automatically shuts down whenever the output voltage drops below 2.96V. An internal power-fail comparator also monitors the output and provides an early warning of low output voltage before the device shuts down. When shut down, the output is latched off until the ON input is pulsed. Turning off the power supply in this way prevents battery damage due to excessive discharge or cell-reversal. Typical applications include portable telephones and other battery-powered equipment where the power supply must be disabled when the battery voltage is low.
The MAX688 and MAX689 do not have an automatic shutdown function, and are identical except for their output voltages. Each device has an active-low shutdown-control input, used to turn its output on or off at any time. As active-low SHDN falls, the device enters a standby mode before fully shutting down. When in standby, the reference and comparators are fully operational, permitting the transition from normal mode to standby mode to occur at a precise voltage level on active-low SHDN.

特性 Features

• Fixed Outputs
• 3.3V (MAX687/MAX688)
• 3.0V (MAX689)
• Directly Drives External PNP Transistor
• 10mA Min Base-Current Drive for > 1A Output
• Low Dropout Voltage:
• 100mV Dropout at 650mA Output (FZT749)
• 40mV Dropout at 200mA Output (FZT749)
• 0.8V Dropout at 4A Output
• Power-Fail Output Monitors the Output Voltage
• Automatic, Latched Shutdown when Output Falls Out of Regulation (MAX687)
• Precision Threshold Shutdown Control (MAX688/MAX689)
• Low Supply Current:
• 150µA Operating
•
• 2.7V to 11.0V Supply Range
• 8-Pin DIP/SO/µMAX® Packages
•

应用 Application

• 汽车电子
• 高效线性稳压器
• 便携式仪表
• 便携式电话
• 存储器电源或备用电源

简介

MAX687属于集成电路（IC）的监控器。由制造生产的MAX687监控器PMIC 监控器用于监视和/或控制电路中的电压轨，能够连接微控制器以维持一定的功率限值。监控器类型包括电池备用电路、监控器、多电压监控器、电源监控器、稳压器/监控器、复位计时器、定序器、简单复位/上电复位、智能开/关控制器、系统管理器、电压检测器和看门狗电路。