RHC 2512 Size 2 Watt Chip Training Module

Introduction Purpose Objectives Content Learning Time Provide a basic overview of Stackpole’s RHC series 2512 size 2 watt surface mount resistors Objectives Discuss current solutions and their limitations Explain the RHC’s unique materials, design and processes Show how the RHC performs vs. standard 2512 size thick film chips Content 10 pages Learning Time 10 minutes Welcome to the Stackpole RHC Training Module. In this module, the function, features, and applications of SEI’s RHC resistors will be presented, and will show how the RHC is characterized.

Current High Power SMD Resistor Solutions SMD wirewounds – are inherently inductive, and are not fusible unless specifically ordered that way; SMD wirewounds will also be much larger, taller, heavier, and more costly than the RHC Parallel combinations of standard flat chips, or melfs – requires more parts, placements, and solder joints increasing costs, product weight, and decreasing overall reliability. The RHC offers a 2 watt power rating in a 2512 size chip package. No other currently available solution provides the same power capability in this size package.

RHC Design, Materials, and Structure Unique resistive element Protective coating Outer plating Substrate Inner plating Inner electrode Materials Remark Substrate Alumina 96％ Bottom Electrode 2512 Standard ： 0.7土0.2 mm TSR1S series　： 2.2土0.2 mm Resistive Element RuO2 Inner electrode Ag/Pd Protective coat Glass・Special Inner Plating Ni Outer Plating Ｓn Compared to standard thick film chips the RHC is designed differently, uses some different materials, and has different manufacturing processes. These three aspects are chosen to maximize the power handling of the part while minimizing the overall heat retained within the part.

Unique Glass and Passivation Overcoat RHC 2512（2512-2Ｗ） Standard chip（2512-1Ｗ） Passivation materials chosen to optimize heat transfer to ambient air Standard chips have low cost materials chosen which tend to hold the heat into the resistor The RHC offers a 2 watt power rating in a 2512 size chip package. No other currently available solution provides the same power capability in this size package.

RHC Unique Manufacturing Process Standard chip（2512-1Ｗ） Reduced hot spot temperature Inner Structure Unique Resistive element The RHC uses a unique calibration process that spreads out and minimizes the effective hot spot temperatures. Standard chips have a single intense hot spot in the middle of the resistor. The RHC is trimmed to value in a unique proprietary manner that creates lower hot spot temperatures compared to standard parts. The heat is distributed much more evenly across the entire resistor element.

RHC Bottom Termination Design The larger bottom terminations disperse heat to the circuit board more efficiently. Standard chips have standard terminations for low cost and compatibility with existing industry standards. RHC（2512-2Ｗ） Standard chip（2512-1Ｗ） Superior heat transfer to PCB Larger Bottom Terminations Temp profile of Chip Surface Leveled Temperature Profile（Temp decrease at heat spot） The end result of these unique features is that the RHC will run 30 to 40 degrees C cooler than a standard chip under identical conditions as shown on the following slide

Temperature Rise RMC vs RHC

2 Watt Resistor Comparison   Two Chips or Melfs Surface Mount Wirewound SEI RHC Series Technology Metal Film / Thick Film Molded Wirewound Thick Film Package Dimensions (in.) .248 L x .300 W x .021 H .435 L x .240 W x .180 H .248 L x ..126W x ..024 H Inductance Very Low High Short Time Overload Capability, 5 Sec pulse 10 watts 50 Watts 18 Watts Resistance Range 0.1 - 22 Mohm 0.01 - 2 Kohm 0.1 ohm – 1 Mohm Placements / Mounting Two 2512 size chips Single 4424 size part Single 2512 size chip Cost Lowest Highest Low Reliability Good Better Board Space Used Medium Largest Smallest The RHC clearly offers the best combination of electrical performance, reliability, and cost. The two chip solution uses twice the board space as well as the other challenges of using multiple parts for a single need. The SMD wirewound is larger, more costly, and has higher inductance.

Future Trends The unique features of the RHC should also provide improved power handling for smaller chip sizes. RHC 2010 and RHC 1206 are currently being researched. Some of the same features may also improve power handling for thin film resistors Stackpole has a wide offering of power resistors to provide the optimal solution for a given application. The requirements for resistance, TCR, tolerance, power, pulse handling, size and cost will determine which series to choose

Summary The RHC is a thick film 2512 size chip resistor capable of dissipating 2 watts, at 70C with only the recommended solder pads and no air movement or additional heat sinking of any kind required. It is passivated in such a way that heat is more efficiently released to the ambient air. It’s unique method of calibration to resistance value minimizes the overall hot spot temperature and helps spread the heat generated over the entire width of the resistor. It has larger bottom terminations to help more efficiently transfer heat from the resistor to the PCB. It has short time overload handling that is 80% better than the equivalent standard thick film chip. It is an inherently non-inductive, fusible, relatively small, light, and inexpensive solution for a 2 watt power requirement. With the proliferation of power electronics in nearly all market segments, high power SMD resistors are becoming more commonplace. Stackpole is committed to providing a wide range of power resistive solutions to meet the needs of this growing market