CSS / CSSH Ultra Precision Current Sensing Chip Resistor Training Module

1
CSS / CSSH Ultra Precision Current Sensing Chip
Resistor Training Module
2
Introduction

• Purpose
• Provide a basic overview of Stackpoles CSS and
  CSSH series of current sense resistor chips
• Objectives
• Explain the important parameters for engineers
  choosing a current sense resistor
• Discuss the advantages that the CSS / CSSH
  specifically provides for those parameters
• Examine applications, end products, and future
  trends for this product
• Content
• 10 pages
• Learning Time
• 10 minutes

Welcome to the Stackpole CSS and CSSH Ultra
Precision Current Sense Chip Resistor Training
Module. This module will explain how the CSS and
CSSH series of resistors is truly one of the most
accurate and stable current sense resistors in
the industry.
3
CSS/CSSH Materials, Design and Construction

• The CSS/CSSH series uses a specially formulated
  resistive alloy to achieve very low TCRs
• As compared to other metal element current sense
  resistors, the CSS/CSSH terminations are
  mechanically crimped onto the resistive alloy for
  higher temperature operation
• Precise resistance values are achieved through a
  proprietary trimming process, providing for
  resistance tolerances down to 0.5

Marking
Metal Alloy
Protective Layer
External Electrode (Sn Plated)
Secondary Electrode (Ni Plated)
Internal Electrode (Cu Plated)
The CSS and CSSH series uses specialized
materials designed to achieve extremely low
resistance values with high precision.  The
unique termination process allows for much higher
temperature operation compared to other
termination methods.  The proprietary trimming
process allows for tolerances down to 0.5.
4
Important Factors for Current Sensing
Stackpoles CSS / CSSH outperforms the
competition

• Low Resistance Values
• High Power Rating
• Improved Power Handling For Given Chip Sizes
• Electrical Stability Low TCR, Tight Resistance
  Tolerance
• High Temperature Operation

With the proliferation of portable electronics,
the design engineer is challenged with reducing
size, improving power handling, and improving
electrical performance. The CSS and CSSH series
is specifically designed with these challenges in
mind.
5
Low Resistance Values for High Efficiency
Requirements

• The lower the resistance value, the less power is
  used for the current sensing operation.
• Stackpole offers resistance values down to 0.25
  milliohms among the lowest currently available
  in the market.
• These low resistance values allow for the highest
  current handling possible.

When efficiency is most important, lower
resistance values for the current sense resistor
is critical. The .25 milliohm value offered by
this series allows for sensing high amounts of
current while keeping the power dissipation as
low as possible.
6
High Power Ratings

• As electronic content and functions increase,
  increasing amounts of current are required to
  power these features.
• As shown on the previous slide, higher current
  levels require higher power ratings.
• In the past, 3 and 4 watt SMD current sense
  solutions were hard to find, large and bulky,
  expensive, limited in resistance values offered,
  and had poor TCR or resistance tolerance.
• The cost effective CSS 2725 and CSSH 2728 offer 4
  watts of power handling with TCR down to 15 ppm
  and tolerances as low as 0.5 in resistance
  values from 0.25 milliohm up to 50 milliohm.

The CSS / CSSH series offers a significant
improvement in stability, precision, and power
handling compared to other surface mountable
solutions available today.
7
High Power Ratings for a Given Package Sizes

• Downsizing electronic products whether to make it
  smaller or to add features usually means
  sacrificing power handling or performance,
  limiting resistance values offered, or increasing
  sense resistor cost.
• Current sensing resistors in general have higher
  power ratings than their standard chip resistor
  equivalents.
• Stackpoles CSSH2512 offers a unique 3 watt power
  rating in a package size usually limited to 2
  watts.

Higher power ratings for 2512 size resistors and
smaller allows the design engineer to utilize the
space normally needed for power management for
other functions to the product or to make the
end product smaller.
8
High Precision Capability Competitive Analysis
Other competitive products require different
series for lower resistance values, another for
lower TCRs, another for tighter tolerances, or
for power ratings higher than 2 watts.
No other product currently available offers the
same combination of low resistance values,
excellent resistance tolerance, and extreme low
TCRs.
9
High Temperature Operation

• The high current / high power environment that
  current sense resistors live in requires
  stability at high temperatures
• The CSS / CSSH offers operation at full rated
  power up to 100C.
• It also offers operation up to 275C, which is
  usually only offered in special series from
  competitors and in limited sizes and resistance
  values.

The CSS / CSSH series offers full power operation
to higher temperatures and offers power derated
operation to higher temperatures than any other
product currently available.
10
Future Developments

• ¼ watt and ½ watt 0805 size chip
• 1 watt 1206 size chip
• 2 watt 2010 size chip
• 5 watt chip
• Lower resistance values for all sizes
• Improved TCR for a wider resistance range

The CSS and CSSH series and the benefits of the
unique materials and manufacturing processes will
lend themselves to keeping pace with the
requirements of the current sensing resistor
market.
11
Summary

• Low Resistance Values available down to 0.25
  milliohms at 50 ppm TCR
• High Power Handling 3 watt 2512 size chip, 4
  watt 2725 and 2728 size chips
• High Precision / Electrical Stability - 0.5
  resistance tolerance and 50 ppm TCR available for
  the entire resistance range.
• Robust High Temperature Operation full rated
  power handling up to 100C and power derated
  operation up to 275C.

The CSS / CSSH series offers unmatched precision,
power handling, and resistance values in a single
series, making it easy to use this single series
a great choice for all current sensing
requirements.