背部偏置包装进展（SE，SG，SH和SJ与SA和SB）

背部偏置包装进展（SE，SG，SH和SJ与SA和SB）

由Daniel Dwyer，All雷竞技竞猜下载egro Microsystems，LLC

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Abstract

除了在过去十年中大厅传感器IC技术的进步之外，Allegro™Microsystems还在背部偏置设备中产生了显着的封装进步。磁路元件和高温材料的使用导致在最终传感器模块产品中使用它们的制造商的总系统成本较低。创新的包装设计和装配技术生产了更小，更强大的设备。

SA and SB Packaging

Allegro's SA and SB represent the first generation of back-biased packages. The SA and SB are composed of mechanically assembled components that are ultrasonically welded into a finished package. The molded Hall-effect IC provides the brain of the system, the pole piece and rare-earth pellet enhance the magnetic circuit, while the housing and end cap provide the package shell.

The SA and SB differ only in their size; the SB is 7 mm long while the SA is 9 mm long. The larger sized SA is used predominately for single-element Hall effect devices that require a larger, more complex magnet system than a differential device.

SE, SG, SH, and SJ Packages

与SA和SB一样，较新的SE，SG，SH和SJ封装具有齿轮齿传感IC的所有所需元件。与SA和SB不同，新包装的功能部件被组装，然后在单个步骤中模制。请参阅图2以查看SB封装的横截面和图3，以查看SG包的横截面。SG包横截面也代表SE，SH和SJ。SE适用于TPO的较大，特别设计的稀土颗粒（真正的电源）和接近感测，而较小的SG，SH和SJ封装接受用于速度和方向感测的差动颗粒。

SE, SG, SH, and SJ Leadframes

These four packages have identical fabrication processes and package dimensions, they do possess distinctly different leadframes. The SE, SG, and SJ have four leads and are used with open-collector, 3-wire devices, while the SH has two wide leads for use with 2-wire devices. The two leads of the SH are wider than those of the SG to facilitate soldering or welding. The SE and SJ have narrower leads than the SH, but they are spread to facilitate soldering and welding.

In all four packages, the leads have been sized and spaced such that forming them against the package does not increase the outer diameter of the package case envelope.

A thermoplastic lead bar molded onto the end of the leads controls lead coplanarity and straightness during shipping and subsequent processing.

塑造特色packag的背面es facilitate orientation and location during subsequent assembly steps. Refer to figure 5.

SE, SG, SH, and SJ Package Advantages

The patented Allegro SE, SG, SH, and SJ packages allow the rare-earth pellet to sit closer to the IC than it does in the first generation packaging (refer to figures 2 and 3). This geometric advantage allows the device to meet large air gap performance with a smaller pellet than that found in standard packages. The resultant small packages fit in the tight spacing dictated by today's gear-tooth sensing applications.

The clearances required for assembly in the SA and SB result in voids throughout the interior of the package (refer to figure 1). Since the SE, SG, SH, and SJ have no such voids, heat dissipation is improved and air entrapment that could occur during subsequent potting operations is eliminated.

A further improvement in heat dissipation is realized through the reduced heat conduction path present in the SE, SG, SH, and SJ packages. Because of the single step molding process, the layer of plastic normally seen between the IC's leadframe and the pellet is eliminated. The increased thermal conductivity signifies greater heat-sinking capacity by the pellet, allowing for operation at higher ambient temperatures. Refer to figure 3.

SE，SG，SH和SJ解决方案优势

• 小包装尺寸
  单身的step thermoset molding allows close pellet/IC proximity for increased magnetic efficiency and reduced pellet size. Single step thermoset molding step also allows for thinner walls and results in smaller package size.
• Simple System Implementation
  Back-biased package with optimized pellet in a small, robust package requires minimal expertise in magnetic circuit design.
• 高温操作
  单身的step thermoset molding for improved heat dissipation provides operation at elevated temperatures.
• 强大的后处理
  单步模塑消除空隙，并阻止在灌封或包覆成型期间产生气泡。
• 易于焊接和焊接
  SE，SH和SJ封装的优化引线配置提供简单的焊接和焊接。