RHC Series
High Power Thick Film Chip Resistor
Features:
•
•
•
•
•
•
Stackpole Electronics, Inc.
Resistive Product Solutions
Handles 2W of power
Resistances from 0.1Ω to 1MΩ
RoHS compliant / lead-free
TCR of ± 100 ppm/ºC
1% and 5% tolerances
Runs significantly cooler than standard thick film 2512 chip
Electrical Specifications
Type / Code
Package
Type
Power Rating
(Watts) @ 70ºC
Maximum
Working
Voltage (1)
Maximum
Overload
Voltage
Resistance
Temperature
Coefficient
Ohmic Range (Ω) and Tolerance
1%
5%
RHC2512
2512
2W
200V
400V
±100 ppm/ºC
0.1 - 1M
0.1 - 1M
(1) Lesser of
√PR
or maximum working voltage.
Please refer to the High Power Resistor Application Note (page 4) for more information on designing and
implementing high power resistor types.
Power Derating Curve:
Performance Characteristics
Percent Rated Power (%)
Test
Moisture Resistance
Load Life
Resistance to Soldering
Temperature Cycling
Thermal Shock
Short Time Overload
Insulation Resistance
Typical
±1%
±1%
±1%
±1%
±1%
±1%
≥1MΩ
100
75
50
Operating Temperature Range: -55ºC to +155ºC
25
0
30
60
90
120
150
180
Ambient Temperature (ºC)
Cº
140
120
100
80
60
40
20
0
0
Temperature Rise
1
2
Hot Spot
Solder Joint
1
2
Load (w)
1
2
Rev Date: 08/25/2011
This specification may be changed at any time without prior notice
Please confirm technical specifications before you order and/or use.
1
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marketing@seielect.com
RHC Series
High Power Thick Film Chip Resistor
Stackpole Electronics, Inc.
Resistive Product Solutions
How to Order
1
2
3
4
5
6
7
8
9
10
11
12
13
R
H
C
2
5
1
2
F
T
1
0
K
0
Product Series
High Power
RHC
Size Power Rating
2W
2512
Code
F
J
Tolerance
Tol
Value
1%
E96, E24
5%
E24
Code
T
Packaging
Description
Size
7" Reel
2512
Plastic Tape
Quantity
4,000
Resistance Value
Four characters with the
multiplier used as the decimal
holder.
0.1 ohm = R100
4.75 ohm = 4R75
10.2 Kohm = 10K2
1 Mohm = 1M00
Legacy Part Number (before January 3, 2011):
SEI Type
Code
Nominal
Resistance
Tolerance
Packaging
RHC
Type
RHC
Description
High Power
2512
Code Wattage Size
2512
2W
2512
10K
1%
Tolerance
1%
5%
Values
E24, E96
E24
SEI Types Pkg Qty
2512
4,000
R
Description
7" reel
plastic tape
Code
R
Rev Date: 08/25/2011
This specification may be changed at any time without prior notice
Please confirm technical specifications before you order and/or use.
3
www.seielect.com
marketing@seielect.com
RHC Series
High Power Thick Film Chip Resistor
Stackpole Electronics, Inc.
Resistive Product Solutions
High Power Chip Resistors and Thermal Management
Stackpole has developed several surface mount resistor series in addition to our current sense resistors,
which have had higher power ratings than standard resistor chips. This has caused some uncertainty and
even confusion by users as to how to reliably use these resistors at the higher power ratings in their designs.
The data sheets for the RHC, RMCP, RNCP, CSR, CSRN, CSRF, CSS, and CSSH state that the rated
power assumes an ambient temperature of no more than 100 degrees C for the CSS / CSSH series and 70
degrees C for all other high power resistor series. In addition, IPC and UL best practices dictate that the
combined temperature on any resistor due to power dissipated and ambient air shall be no more than 105C.
At first glance this wouldn’t seem too difficult, however the graph below shows typical heat rise for the CSR
½ 100 milliohm at full rated power. The heat rise for the RMCP and RNCP would be similar. The RHC with
its unique materials, design, and processes would have less heat rise and therefore would be easier to
implement for any given customer.
The 102 degrees C heat rise shown here would indicate there will be additional thermal reduction techniques
needed to keep this part under 105C total hot spot temperature if this part is to be used at 0.75 watts of
power. However, this same part at the usual power rating for this size would have a heat rise of around 72
degrees C. This additional heat rise may be dealt with using wider conductor traces, larger solder pads and
land patterns under the solder mask, heavier copper in the conductors, vias through PCB, air movement, and
heat sinks, among many other techniques. Because of the variety of methods customers can use to lower
the effective heat rise of the circuit, resistor manufacturers simply specify power ratings with the limitations
on ambient air temperature and total hot spot temperatures and leave the details of how to best accomplish
this to the design engineers. Design guidelines for products in various market segments can vary widely so it
would be unnecessarily constraining for a resistor manufacturer to recommend the use of any of these
methods over another.
Note:
The final resistance value can be affected by the board layout and assembly process, especially the size of the
mounting pads and the amount of solder used. This is especially notable for resistance values
≤
50 mΩ.
This should be taken into account when designing.
Rev Date: 08/25/2011
This specification may be changed at any time without prior notice
Please confirm technical specifications before you order and/or use.
4
www.seielect.com
marketing@seielect.com
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