搜「SM712」這個型號物料，會發現，客戶還經常搜：SM712是什麽二極管、SM712參數、SM712產品手冊、SM712廠家、SM712現貨、SM712價格、SM712封裝、SM712封裝尺寸、SM712應用、SM712靜電防護器件可以用在RS-485接口上嗎？不同的客戶，會碰到不同的問題。SM712這顆常用型號ESD靜電防護器件，其實很多新老電子工程師都非常熟悉的，甚至比東沃電子（DOWOSEMI）專業生產ESD二極管還專業。接下來，二極管廠家東沃電子（DOWOSEMI）針對SM712為您詳細展開介紹一下！

查閱東沃電子「ESD-SM712 Datasheet」產品手冊可知：

1）ESD靜電防護器件SM712特性

√ Protects two -7V to 12V lines
√ Low capacitance
√ Low clamping voltage
√ Solid-state silicon avalanche technology
√ IEC 61000-4-2 (ESD) ±15kV (air), ±8kV (contact)
√ IEC 61000-4-4 (EFT) 40A (5/50ns)
√ IEC 61000-4-5 (Lightning) 12A (8/20μs)

2）ESD靜電防護器件SM712參數

√ 峰值脈沖功率Peak Pulse Power ( tp =8/20μs): 400W
√ 峰值脈沖電流Peak Pulse Current ( tp =8/20μs): 12A
√ 工作電壓Reverse Stand-Off Voltage: 12V和7V
√ 擊穿電壓Reverse Breakdown Voltage: 13.3V和7.5V
√ 鉗位電壓Clamping Voltage: 26V
√ 漏電流Reverse Leakage Current: 1uA
√ 結電容Junction Capacitance: 45pF 75pF
√ 封裝Package: SOT-23

3）ESD靜電防護器件SM712應用

EIA RS-485 specifies a ±7V ground difference between devices on the bus. This permits the bus voltage to range from +12V (5V + 7V) to -7V (0 - 7V). The SM712 is designed to protect two RS-485 data lines in extended common mode applications. The SM712 may be used to protect devices from transient voltages resulting from ESD, EFT, and lightning. The device is designed with asymmetrical operating voltages for optimum protection. The TVS diodes at pins 1 and 2 have a working voltage of 12 volts. These pins are connected to the differential data line pairs. The TVS diodes at pin 3 have a working voltage of 7 volts. Pin 3 is connected to ground. The internal TVS diodes of the SM712 will protect the transceiver input from positive transient voltage spikes greater than 12V and Negative spikes greater than 7V. A series current limiting resistor may be added in applications requiring enhanced surge immunity.

由此可知，SM712是RS-485接口常用的靜電ESD防護器件，也是客戶常咨詢的ESD二極管。關於SM712的價格、現貨、交期等其他方面的問題，可以咨詢東沃電子銷售工程師：136 7581 6901（微信同號）朱工