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UMW UC3845B
Configuration
1 options
Configuration
25+
Available for RFQ
Technical data
Product details
19
specifications
Core information
- Product name
- UMW UC3845B
- Type
- UMW
- Minimum package
- 2500 圆盘
Technical parameters
- Electronic Component
- Electronic Component
- Electronic Component
- UMW
- Electronic Component
- UC3845B
- Electronic Component
- 1
- Package
- SOP-8
- Electronic Component
- DC-DC Power Supply IC
- Electronic Component
- 0.2g
- Electronic Component
- 1
- Features
- Frequency Synchronous
- Electronic Component
- BM0227324867
- Operating Temperature
- 0℃~+70℃@(TA)
- Switching Frequency
- 50kHz
- Output Type
- Electronic Component
- Output Channel Count
- 1
- Static Current(Iq)
- 17mA
- Electronic Component
- Electronic Component
For datasheets, package documents, compatible-part guidance, or other technical resources, contact WMSIC customer service. Availability is confirmed case by case.
UC3845B 产品概述
一、概述
UC3845B 是一款高性能的电流模式 PWM 控制器，常用于离线与非隔离开关电源的主控芯片。基于固定频率振荡器、误差放大与电流比较结构，适合进行升降压或优化型非隔离 DC-DC 变换器设计。按给定基础参数，本器件在工作温度 0℃+70℃（TA）条件下、开关频率约 50kHz 时表现稳定，适配输入范围 7.6V30V 的非隔离 AC-DC/DC-DC 控制方案。常见封装为 SOP-8，国内品牌如 UMW（友台半导体）有对应器件版本。
二、主要功能与特点
- 电流模式 PWM 控制：内置电流比较器实现峰值限制和快速过流保护，利于快速响应负载突变与并联调节。
- 可调振荡器：通过外接 RT/CT 设置开关频率，调至 50kHz 可在效率与电感体积间取得平衡。
- 精确参考与误差放大：内部参考源与误差放大器用于输出电压闭环控制，支持频率补偿网络优化动态性能。
- 启动与欠压锁定（UVLO）：保证上电和掉电过程的可靠性，防止器件在欠压下异常工作。
- 门极驱动能力：输出级能直接驱动功率 MOSFET 门极，简化外围驱动电路设计。
- SOP-8 封装，便于批量生产与常规 PCB 布局。
三、典型应用场景
- 非隔离降压（Buck）与升降压（SEPIC）直流稳压模块；
- 低成本开关电源、工业电源模块；
- 适配器、LED 驱动以及要求中等开关频率（≈50kHz）的电源解决方案。
四、设计与调试要点
- 频率设定：50kHz 可通过 RT/CT 计算并微调，注意元件容差对频率的影响。
- 电流采样：选择合适的分流电阻或电流变压器，确保峰值电流限制准确且具有足够的噪声余量。
- 补偿网络：COMP/反馈回路需根据输出滤波器特性设计零点与相位裕度，避免振荡或响应迟滞。
- 启动与供电：若系统 VCC 由输出供给，需设计启动电阻或辅助绕组，保障启动电流与稳态供电稳定。
- 热与 EMI 管理：SOP-8 封装需注意散热路径与 PCB 大地平面；开关频率与布局直接影响 EMI，需要合适的滤波与布线优化。
五、封装与品牌
UMW（友台半导体）提供的 UC3845B 通常为 SOP-8 封装，便于直接替换市场上同类产品。采购时注意查看器件批次、参数一致性以及应用手册与典型电路图。
六、注意事项
- 非隔离设计需特别注意输入与输出地线共模回路，确保安全与可靠性；
- 根据工作温度范围（0℃~+70℃）核对应用环境，必要时选择更宽温度等级器件；
- 在高噪声或高温环境下，适当提高滤波与保护裕量，保证长期稳定运行。
以上为 UC3845B 在中低频（≈50kHz）非隔离电源设计中的概述与实用要点。实际设计中建议参考具体器件数据手册与厂商典型应用电路，依据目标效率与成本对磁性元件、MOSFET 及滤波器件进行优化匹配。
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