器件种类：霍尔传感器（风扇/马达专用）
品牌厂商：Melexis（美国）
产品型号：US890、US891
封装外形：TO-92-4Pin（SIP-4L）
包装规格：胶袋包装，每包1000只
销售联络：手机 13603016645，QQ:  511326471

特点和优点：
        峰值输出电流高达1200毫安
        低启动电压
        低输出电阻
        高灵敏度集成霍尔传感器
        低功耗CMOS和功率MOSFET
        内置输出保护，钳位二极管
        循环保护、自动重新启动
        综合转速表（US890）或报警（US891）信号输出保护
        低成本
        2线圈与风扇驱动电路，4脚封装，符合RoHS

产品应用范围：
        5V、12V直流无刷电机、风扇电路
        个人电脑、服务器、笔记本电脑散热风扇电路
        电源散热风扇电路
        各种大小尺寸的风扇电路

一般描述
        US890、US891是一个用于驱动两个线圈无刷直流电动机和风扇芯片解决方案。
        基于Melexis公司先进的CMOS工艺，该IC包含一个霍尔效应传感器，动态偏移校正和1200毫安峰值输出电流能力强大的输出驱动器。
        专为驱动大风扇设计。使设备经过优化后，启动电压灵敏度高。
        频率发生器或旋转检测可用。
        漏极开路输出，可以方便地与任何连接，如：硬件监控或超级I / O芯片的外部接口。
        这些功能相结合，Melexis的专利没有VDD电压设计，可安装在小型4脚封装的集成电路。
        偏低输出线圈驱动器得到充分保护，对开关瞬态保护。内建反向电压保护二极管可防止IC因反向电压过高而损坏。
        US890其内部由能隙基准电压源、霍尔元件、放大器、施密特整形电路、提供转换时的迟滞。
        在US891，漏极开路旋转检测输出低电平路是在正常电机的旋转。
        其内部温度补偿电源可使传感器在很宽的温度范围内获得均匀的灵敏度。

Features and Benefits
　Peak output current up to 1200mA
　Low start-up voltage
　Low output resistance
　High sensitivity integrated Hall Sensor
　Power-efficient CMOS and power MOSFETs
　Built-in output protection clamping diode
　Locked rotor protection and auto-restart
　Integrated tachometer (US890) or alarm (US891) signal protected output
　Low cost
　2-coil fan driver with FG/RD output in RoHS Compliant 4-pin VK package

Application Examples
　5V/12V DC brushless motor/fan
　PC, server, laptop cooling fan
　Power supply cooling fan
　Large and small fan size

General Description
        The US890/891 is a one-chip solution for driving two-coil brushless DC motors and fans.
        Based on the advanced Melexis CMOS process, the IC contains a Hall-effect sensor, dynamic offset correction and powerful output drivers with 1200mA peak output current capability.
        Specially designed for driving large fans, the device is optimized for low start-up voltage.
        Frequency Generator or Rotation Detection is available. The open-drain output makes easier the connectivity with any external interface such as hardware monitoring or Super I/O IC.
        These features are combined with the Melexis patented no-VDD design to fit the IC in a small 4-pin VK package.
Detailed General Description
        The US890/891 is a one-chip solution for driving two-coil brushless DC motors and fans. Based on advanced Melexis CMOS process, the chip contains a Hall-effect sensor, dynamic offset correction and powerful output drivers with 1200mA peak output current capability.
        The low side output coil drivers are fully protected against switching transients. So an external zener diode is not needed to cut the high voltage spikes induced by the motor coils.
        The US890 has an open-drain integrated tachometer FG output that follows the Hall signal. In the US891, the open-drain rotation detection output RD is active low during normal spinning of the motor. It goes high when the flux switching frequency becomes too low, which means the motor is blocked.
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