RHC 2512 Size 2 Watt Chip Training Module

1
RHC 2512 Size 2 Watt ChipTraining Module
2
Introduction

• Purpose
• Provide a basic overview of Stackpoles RHC
  series 2512 size 2 watt surface mount resistors
• Objectives
• Discuss current solutions and their limitations
• Explain the RHCs 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 SEIs RHC resistors will be
presented, and will show how the RHC is
characterized.
3
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.
4
RHC Design, Materials, and Structure
Unique resistive element
Protective coating
Outer plating
Substrate
Inner plating
Inner electrode
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.
5
Unique Glass and Passivation Overcoat
Standard chip(2512-1W)
RHC 2512(2512-2W)

• 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.
6
RHC Unique Manufacturing Process
Standard chip(2512-1W)
RHC(2512-2W)
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.
7
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)
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
8
Temperature Rise
RMC vs RHC
9
2 Watt Resistor Comparison
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.
10
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
11
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.
• Its 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