元器件减额法指引

作成日期：2007/9/18 1/5 修改日期：2008/4/12 元器件减额法指引 Component Derating Guideline 1. 目的 /Purpose 元器件减额法的目的是改善一个产品的固有 设计 领导形象设计圆作业设计ao工艺污水处理厂设计附属工程施工组织设计清扫机器人结构设计 可靠度,增加它的操作的边缘, 而且最后减少担保费用。 目标将达成比较强健的设计。 The purpose of component derating is to improve a product’s inherent design reliability, increase its operating margins, and ultimately reduce warranty costs. The goal is to achieve a more robust design. 2. 范围 /Scope 如果客户沒提供减额法指引，这将适用于可立克科技设计的所有电源产品。 This document is applicable to Click’s power supply if customer’s derating guideline is not available. 3. 定义/Definitions 减额：施加在部件上的温度，电压，电流等应力应低于该部件的最大额定应力。 Derating: The practice of limiting electrical, thermal, voltage and current stresses on a part to levels below its maximum rated stress level. 应力比：元器件实际工作时测到的应力除以它的额定值。应力比用百分比表示，它是产品工作在规格内最坏的温度、电压、电流等条件下测试并计算出来。 Stress ratio: The measure of the stress applied to a component relative to its maximum rating. The stress ratio is calculated by dividing the operating stress by the maximum rated stress and is stated in terms of percent of maximum rated value. This stress ratio is calculated under worst case thermal, voltage and current conditions as specified in the product requirements document. 4. 减额法 标准 excel标准偏差excel标准偏差函数exl标准差函数国标检验抽样标准表免费下载红头文件格式标准下载 /Derating Criteria: 减额法指引是根据零件的SOA曲线定出来的。假如零件没有被定义 SOA曲线，则定义为最大额定值减额10%。并需考虑实际应用在最高温度，工作在最高电压及最大电流状况。 The derating guideline is come out from components’ SOA curve. The derating was specified 10% below its maximum rating, if component data didn’t specify the SOA curve. Please take into account the fact that maximum rating may vary over temperature, applied voltage and current. 4.1 电阻减额指引/Resistor derating guidelines ** 高压侧的电阻被限制使用高压电阻，而普通电阻被禁止使用在高压侧。 ** High voltage side resistor is restricted to use high voltage type resistor and traditional resistor is prohibited using in high voltage side. 零件类型/ Component Type 参数/Parameter 减额度/ Derating Factor 备注/Notes 绕线型功率电阻/ Wire wound Power 功率/Power 80% 电压/Voltage 90% 温度/Temperature PCB-10℃ Body temp allowed to reach 90% max temp if mounted off PCB 金属膜电阻Thick/Thin Film (MF) 贴片电阻Thick/Thin Film Chip (CH) 功率1/4W /Power 1/4W 80% 功率1/4W /Power 1/8W 80% 温度/Temperature 90% 电压/Voltage 90% 碳膜电阻Composition (CF) 功率/Power 80% 电压/Voltage 90% Below Max. Temp. Limit PCB-10℃ 可调电阻/ Variable (VR) 功率/Power 80% 电压/Voltage 90% Below Max. Temp. Limit PCB-10℃ 热敏电阻/ Thermistor 功率/Power 80% Below Max. Temp. Limit 30℃ For primary side NTC. Below Max. Temp. Limit 10℃ For protection or fan speed control circuit NTC. 保险电阻/Fusible Resistor 功率/Power 60% 4.2 Miscellaneous derating guidelines 零件类型/ Component Type 参数/Parameter 减额度/ Derating Factor 备注/Notes 保险管Fuses 电流Current (I2T) 80% 拔动/敏感/旋转/按钮开关Toggle / Sensitive / Rotary / Push-Button Switches 电流Current 80% 4.3 整流器件减额指引/Rectifiers derating guidelines 4.3.1 Diodes, Signal/Switch, General purpose 零件类型/ Component Type 参数/Parameter 减额度/ Derating Factor 量测状态/Measurement state (N) (T) 反向电压/Reverse Voltage 90% 100% 电流/Current 90% 温度/Temperature (Tj) 90% 备注/Note: (N)常态/ Normal (T)暂态/ Transient 4.3.2 Diodes, Bridge Rectifiers (switching) 参数/Parameter 减额度/ Derating Factor 备注/Notes 量测状态/Measurement state (N) (T) 反向电压/Reverse Voltage 90% 100% 80% of I2t 正向电压/Forward Current 90% 温度/Temperature (Tj) 90% 4.3.3 Diodes, Schottky 参数/Parameter 减额度/ Derating Factor 备注/Notes 量测状态/Measurement state (N) (T) 反向电压/Reverse Voltage 90% 100% Vr can reach to its max rating if it is an Avalanche rated device, but not under normal operation. Parallel schottky diodes must be thermally bonded 正向电压/Forward Current 95% 温度/Temperature (Tj) 90% 备注/Note: (N)常态/ Normal (T)暂态/ Transient 4.3.4 Diodes, Zener 参数/Parameter 减额度/ Derating Factor 备注/Notes 功率/Power 80% 温度/Temperature (Tj) 90% 4.4 Transistor derating guidelines 4.4.1 Transistor (BJT) 参数/Parameter 减额度/ Derating Factor 备注/Notes 量测状态/Measurement state (N) (T) 电压/Voltage 90% 100% 75% of rated Vbe 电流/Current 80% 温度/Temperature (Tj) 90% 4.4.2 MOSFET 参数/Parameter 减额度/ Derating Factor 备注/Notes 量测状态/Measurement state (N) (T) 电压/Voltage 90% 100% Avalanche current and energy within 50% of rating. But avalanche is not allowed under normal operation. 电流/Current 80% 温度/Temperature (Tj) 90% 备注/Note: (N)常态/ Normal (T)暂态/ Transient 4.4.3 Thyristors, SCR, TRIACS 参数/Parameter 减额度/ Derating Factor 备注/Notes 关闭电压/Off-state Voltage 90% 功率/Power 80% 开启电流/On-state-Current 80% 温度/Temperature 90% 4.5 Capacitor derating guidelines 零件类型/ Component Type 参数/Parameter 减额度/ Derating Factor 备注/ Notes 电解电容/ Electrolytic Aluminum 电压/Voltage 90% Bulk Cap Voltage 100% 电流/Current 100% Bulk Cap Current 100% 温度/Temperature 90% 寿命/Lifetime (at 35℃) 3 years 陶瓷贴片电容/ Ceramic Chip (CH) 电压/Voltage 90% 温度/Temperature 90% Ceramic Multiplayer 电压/Voltage 90% 温度/Temperature 90% 陶瓷电容/Ceramic Disk (CD) 电压/Voltage 90% 温度/Temperature 90% Film, Mica 电压/Voltage 90% 温度/Temperature 90% Polyester (Mylar) Poly Prop 电压/Voltage 90% Power Supply X Cap. Voltage 100% 温度/Temperature 90% Tantalum Electrolytic Or Solid (TA) 电压/Voltage 80% 温度/Temperature 90% 4.6 Microcircuits IC derating guidelines 参数/Parameter 减额度/ Derating Factor 备注/Notes 量测状态/Measurement state N 电压/Voltage (Vcc) 90% 电流/Current 90% 功率/Power 90% 温度/Temperature (Tj) 90% 4.7 Transformers and Inductive component derating guidelines 类型/Types 减额度/ Derating Factor 备注/Notes 线圈/Coils 绝缘等级/Insulation class 允许最高高温度/Max allowable Temp Class F 130 ℃ Class B 110 ℃ Class A 90 ℃ 磁芯/Core Iron Power Core (Primary circuit) 65% High flux change or above line frequency application, example active PFC choke. Iron Power Core (Secondary circuit) 90% Low flux change or <= line frequency application such as input EMI D-choke. Ferrite Core 90% Max flux density kept 90% of Bsat @ 100 ℃ Column /MPP/High Flux Core 90% Amorphous Core 90% 11.5 参考文献/References MIL-P-11268L Electronic parts derating requirement SUN micro’s Design Guidelines 910-3733-01 Rev A NOKIA’s power supply derating instructions E10015695QE_00Dell’s component derating guideline 9E154 Rev A00