ICP-S Technical Manual
Overcurrent Protection Elements
Rev.A
1/13
ICP-S Technical Manual
ICP-S
1. Overview
The ICP-S is an IC protector of surface mounting type developed as an element for the protection of ICs from output
short-circuiting damage. The internal resistance of this lightweight, compact overcurrent protection element is low, as long
as the steady-state current of the element does not exceed the rated DC or AC current. The ICP-S, however, turns off ICs
instantly if the steady-state current reaches or exceeds the breaking current of the ICP-S.
2. External Dimensions (Unit: mm)
4.0
0.1
2.8
0.2
1.15
0.1
8.0
0.2
5.3
0.2
3.5
0.05
(Mark: TN)
0~0.5
2.3
0.2
3.5
0.2
2.0
0.05
1.75
0.1
4.0
0.1
0.4
0.1
0~0.1
1.8
0.1
0.6
1.0
3.2
0.2
2.0
0.1
1.55
0.1
2.5
0.1
3.0
0.1
+
0.1
-
0
1.5
TN direction
3. Features
1) Instantly breaks currents with a low potential drop.
(See 3-1 Potential Drop Comparison)
2) Compact surface-mounting model.
(See 2. External Dimensions)
3) Unlike fuses, there is no steady-state current reduction with the rated current applied. No derating is necessary.
4) Minimal breaking point dispersion.
(See the graph in 3-2 Breaking Current Dispersion
Characteristics)
5) Excellent temperature characteristics
(See the graphs in 3-3 Temperature Characteristics)
The fluctuation of the breaking current caused by temperature changes is minimal.
Wide operating temperature range:
-
55
C to
+
125
C
6) Excellent vibration resistance.
7) UL-approved product with certification No. 107856.
8) No deterioration or circuit breaking caused by static electricity.
ICP-S Technical Manual
Overcurrent Protection Elements
Rev.A
2/13
3-1 Potential Drop Comparison (ICP-S VS Fuse)
ICP-S1.0 (Rated Current: 1 A)
2.0A
1.8A
1.5A
1.0A
DC
500mV / div
NORMAL
10mSEC / div
+
Fuse (Rated Current: 1 A)
4.0A
3.0A
2.0A
1.0A
DC
500mV / div
NORMAL
10mSEC / div
+
ICP-S Technical Manual
Overcurrent Protection Elements
Rev.A
3/13
0
0.01
0.1
1
10
100
1000
1
Breaking Current (A)
Breaking time (mec)c
2
3 4
5 6
7
8
9 10 11 12 13 14 15 16 17 18 19 20
Breaking Time (Reference) Effective Value and Dispersion Data (ICP-S1.0)
n=5pcs
5lot
typ
max
min
-
50
0
0.7
0.8
0.9
1.0
1.1
1.2
Ambient temperature Ta (
C)
Breaking current ratio
-
25
0
25
50
75
100
125
Breaking Current vs.
Ambient Temperature Characteristics (ICP-S)
0
0
0.5
S0.5
S0.7
S1.0
S1.2
0.7
1.0
1.2
1.5
2.0
2.5
3.0
Ambient temperature Ta (
C)
Current applied (A)
25
50
75
100
125
150
175
Rated Current Derating Curve (ICP-S)
3-2 Breaking Current Dispersion Characteristics
3-3 Temperature Characteristics
ICP-S Technical Manual
Overcurrent Protection Elements
Rev.A
4/13
4. Selection Flowchart
Type of steady-state current?
DC
No
Yes
No
No
Yes
Yes
Pulse
Surge current
included
Inrush current
included
Check with the I
2
t characteristics graph.
Change the ICP model
to satisfy the condition.
Lower the
open-circuit voltage.
Change the ICP model to
satisfy the condition.
Does the steady-state
current not exceed the rated
current of the ICP?
Is the rated voltage (i.e., the
open-circuit voltage when the ICP
breaks the current) 50 V or below?
Is the breaking current (the maximum
abnormal current) within a range
of 2x to 10x of the ICP's rated current?
The selection is OK.
ICP-S0.5
ICP-S0.7
ICP-S1.0
ICP-S1.2
0.5
0.7
1.0
1.2
1.0 to 5.0
1.4 to 7.0
2.0 to 10.0
2.4 to 12.0
TYPE
Rated current (A)
Breaking current (A)
List of ICP-S Models
The I
2
t-t characteristic graph (i.e., the Joule integral sheet) provides necessary data used to check
how the life of the ICP-S is influenced by heat cycling or mechanical fatigue caused by repetitive
current pulses.
ICP-S Technical Manual
Overcurrent Protection Elements
Rev.A
5/13
5. Checks with I
2
t-tCharacteristic Graph
If the steady-state current includes a pulse, surge, or inrush-current, use the I
2
t
graph and check that the ICP will not deteriorate regardless of the mode of the
current or the ICP will not break the steady-state current while the ICP is in operation.
Even though the Joule integral value of the current wave form designed at your end is
within the safety area, it is recommended that you confirm the steady-state current for
the safety of the components
Refer to the next section, calculate the I
2
t value, and check the position of the I2t value
in the graph. If the value is in the safety area, it is okay to use the selected ICP model.
If the value is, however, beyond the safety area, use an ICP model with higher ratings.
Note: The inspection and selection of the ICP according to the Joule integral value is
absolutely based on the results of the approximation of the current wave form.
Be sure to inspect all the current wave forms of your application, or otherwise the safety
of the application will not be fully ensured.
Consider a safety margin with the dispersion of component characteristics taken into
calculation when inspecting and selecting the ICP, if it is impossible to check the worst
current wave form.
I
2
t-t Graph
Breaking current area: The ICP breaks the current in this area.
Deterioration area: Although the ICP does not break the current instantaneously,
the ICP may break the current as a result of ICP deterioration.
Marginal area: The area where the risk of ICP deterioration is low.
Basically avoid using this area.
Safety area: The ICP will not deteriorate or break the current.
Precautions
t (s)
I
2
t (A
2
- ms)
Breaking
current area
Safety area
Deterioration
area
Margin area
I
2
t-t Graph
ICP-S Technical Manual
Overcurrent Protection Elements
Rev.A
6/13
6. I
2
t Calculation of a Variety of Wave forms
If the steady-state current includes a pulse, surge, or inrush current, calculate the I
2
t of
the wave form of the current. The following graphs and formulas show how to calculate
a variety of wave forms.
The charged wave form is segmented as shown below. The Joule heat
generated during each segmented period is plotted onto a Joule integral
sheet.
1) Triangular
wave form
0
t
Im
I
2
t = Im
2
t
3
1
2) Rectangular
wave form
I
2
t = Im
2
t
0
t
Im
3) Irregular
wave form
4) Charged or
discharged
wave form
0
t
I1
I2
I
2
t = I
1
I
2
t + (I
1
-
I
2
)
2
t
3
1
1
2
3
4
5
Segments 1 through 4 are treated as
irregular wave forms and calculated,
while segment 5 is treated as a
triangular wave form and calculated.
ICP-S Technical Manual
Overcurrent Protection Elements
Rev.A
7/13
7. ICP-S Test Example
7-1 Example 1
Current mode: DC
Model: ICP-S1.0
Wave form:
DC
1A
2A
5A
Test:
The current values of all segmented periods are plotted respectively as shown in attached graph 1.
1 A: The steady-state current is in the safety area where the ICP-S will not deteriorate or break the current.
2 A: The ICP-S will break the steady-state current in the breaking current area in approximately 100 ms.
5 A: The ICP-S will break the steady-state current in the breaking current area in approximately 0.7 ms.
7-2 Example 2
Current mode: A single pulse
Model: ICP-S1.0
Wave form: A current of 1.75 A flows for a period of 20 ms.
Results: The steady-state current is in the critical area. If the single pulse is repeated intermittently,
the ICP-S will deteriorate or break the current in the end.
Test:
With pulse current: I
2
t = 1.75
2
20
= 61 (A
2
ms) at 20ms (See graph 2)
20ms
1.75A
ICP-S Technical Manual
Overcurrent Protection Elements
Rev.A
8/13
0.001
0.01
0.1
1
10
100
1000
10000
0.01
Time (msec)
I
2
t (A
2
- ms)
0.1
1
10
100
1000
10000
100000
I
2
t-t
Characteristic Curve (ICP-S1.0)
Graph 1
Ta=25
C
B :Effective pulse critical line
(with no margin)
C :Effective pulse recommended
critical line (with margin)
0.001
0.01
0.1
1
10
100
1000
10000
0.01
Time (msec)
I
2
t (A
2
- ms)
0.1
1
10
100
1000
10000
100000
I
2
t-t
Characteristic Curve (ICP-S1.0)
Graph 2
Ta=25
C
A :Effective pulse breaking
line (with no margin)
B :Effective pulse critical line
(with no margin)
C :Effective pulse recommended
critical line (with margin)
DC 5A
DC 2A
DC 1A
61 (A
2
ms) at 20ms
A :Effective pulse breaking
line (with no margin)
ICP-S Technical Manual
Overcurrent Protection Elements
Rev.A
9/13
Joule Integral Calculation of Irregularly Increasing or Decreasing Current
Current mode: Irregular triangular wave form
Model: ICP-S1.0
Wave form:
Wave form approximation: The above wave form is approximated by electrically calculating the Joule
integral of each segment of the current wave form. In consideration of the heat
cycling and mechanical fatigue of the ICP-S, however, a practical Joule
integral value is calculated from an approximation curve obtained by
connecting the peak of each current wave form.
Test: Obtain the approximated value by substituting the values into the formula
(triangular wave form I
2
t = 1/3
Im
2
t).
I
2
t = 1/3
3
2
A
1ms = 3 (A
2
ms)
Plotting test:
Test results: The steady-state current does not exceed line C. Therefore, it is considered that the ICP-S
will not deteriorate or break the current.
1ms
3A
Actual wave form
Approximation curve for
Joule integral calculation
0.001
0.01
0.1
1
10
100
1000
10000
0.01
Time (msec)
I
2
t (A
2
- ms)
0.1
1
10
100
1000
10000
100000
I
2
t-t
Characteristic Curve (ICP-S1.0)
Graph 2
Ta=25
C
A :Effective pulse breaking
line (with no margin)
B: Effective pulse critical line
(with no margin)
C: Effective pulse recommended
critical line (with margin)
3 (A
2
ms) at 1ms
ICP-S Technical Manual
Overcurrent Protection Elements
Rev.A
10/13
Joule Integral Calculation of Irregularly Increasing or Decreasing Current
Current mode: Irregular wave form + triangular wave form
Model: ICP-S1.2
Wave form:
Wave form approximation: The above wave form (electric charge wave form) is approximated as an
irregular wave form to calculate the Joule integral of the wave form.
Test:
Plotting test:
Test results: The steady-state current is between lines B and A. Therefore, it is considered that the
ICP-S will deteriorate or break the current due to the repetitive pulses.
Actual wave form
Approximation curve for Joule
integral calculation
10A
8A
6A
2A
3.5A
0.1ms
0.35ms
0.25ms
0.55ms
0.06ms
Item
Peak
current
Im
(A)
t
(ms)
(ms)
(A
2
ms)
Formula
Coefficient
Im
2
t A
2
ms)
No.
1
10
0.06
0.06
4.88
9.81
17.88
19.81
20.54
4.88
10
8
0.06+1/3
(10
-
8)
2
0.06=
8
6
0.1+1/3
(8
-
6)
2
0.1=
6
3.5
0.35+1/3
(6
-
3.5)
2
0.35=
3.5
2
0.25+1/3
(3.5
-
2)
2
0.25=
1/3
(2)
2
0.55=
4.93
8.07
1.93
0.73
0.16
0.51
0.76
1.31
0.1
0.35
0.25
0.55
8
6
3.5
2
2
3
4
5
Segmented
period
Lapsed
time
Joule integral
Accumu-
lation
1
3
2
4
5
0.001
0.1
1
10
100
1000
10000
100000
0.01
I
2
t (A
2
- ms)
0.1
1
10
100
1000
10000
100000
Time (msec)
I
2
t-t Characteristic Curve
(ICP-S1.2)
Ta=25
C
A : Effective pulse breaking
line (with no margin)
B : Effective pulse critical
line (with no margin)
C : Effective pulse recommended
line (with margin)
ICP-S Technical Manual
Overcurrent Protection Elements
Rev.A
11/13
8. Application Circuit Example
8-1 Recommended Flow Soldering Conditions
8-2 Recommended Reflow Soldering Conditions
8-3 Recommended Copper Pattern on PCB
25
50
100
100
C
(
C)
Preheating
Soldering
Manual soldering conditions
Soldering iron temperature: 350
C max.
Soldering time: 3 seconds max.
Solder temper
ature
Natural cooling
120
C
2 minutes min.
5 minutes min.
1 minute min.
10 seconds min.
230
C
260
C
150
200
250
300
0
50
100
(
C)
Preheating
speed
A peak temperature of at least 230
C is recommended. If the peak temperature is less than 230
C, it is recommended to
make some adjustments, such as the retention of the peak temperature and soldering time longer and an increase in the thickness
of solder paste.
T
emper
ature
1 to 5
C / sec
Preheating
120 to 160
C,
50 to 120 sec
Peak temperature
230 to 260
C, 10sec Max.
Cooling
60sec Min.
Number of reflow times: 2 TIMES Max.
Reflow soldering
(High-temperature
retention time)
200
C,
30 to 60 sec
Reflow heating temperature
1 to 5
C / sec
150
200
250
1.8 to 2.4
1.6 to 2.0
4.0 to 5.0
ICP-S Technical Manual
Overcurrent Protection Elements
Rev.A
12/13
9. Application Circuit Examples
9-1 Power Supply Circuit
9-2 DC-DC Converter
9-3 Motor Control
ICP
ICP
ICP
M
ICP
V
CC
ICP-S Technical Manual
Overcurrent Protection Elements
Rev.A
13/13
10. Precautions
1. Set the breaking current two to ten times as high as the rated current.
Use the ICP-S so that the open-circuit voltage between the terminals after the ICP-S breaks
the current will be a maximum of 50 V. Unless the ICP-S is used under these conditions, the
mold may be damaged or internal resistance may remain after the ICP-S breaks the current.
2. Do not use the ICP-S for the primary side of commercial power supply, or otherwise the mold
may be damaged by arcing after the ICP-S breaks the current.
0.001
0.01
0.1
1
10
100
1000
10000
0.01
Time (msec)
I
2
t (A
2
- ms)
0.1
1
10
100
1000
10000
100000
I
2
t-t
Characteristic Curve (ICP-S0.5)
Ta=25
C
A :Effective pulse breaking
line (with no margin)
B: Effective pulse critical line
(with no margin)
C: Effective pulse recommended
critical line (with margin)
0.001
0.01
0.1
1
10
100
1000
10000
0.01
Time (msec)
I
2
t (A
2
- ms)
0.1
1
10
100
1000
10000
100000
I
2
t-t
Characteristic Curve (ICP-S0.7)
Ta=25
C
A :Effective pulse breaking
line (with no margin)
B: Effective pulse critical line
(with no margin)
C: Effective pulse recommended
critical line (with margin)
0.001
0.01
0.1
1
10
100
1000
10000
0.01
Time (msec)
I
2
t (A
2
- ms)
0.1
1
10
100
1000
10000
100000
I
2
t-t
Characteristic Curve (ICP-S1.0)
Ta=25
C
A :Effective pulse breaking
line (with no margin)
B: Effective pulse critical line
(with no margin)
C: Effective pulse recommended
critical line (with margin)
0.001
0.01
0.1
1
10
100
1000
10000
0.01
I
2
t (A
2
- ms)
0.1
1
10
100
1000
10000
100000
Ta=25
C
Time (msec)
I
2
t-t
Characteristic Curve (ICP-S1.2)
A :Effective pulse breaking
line (with no margin)
B: Effective pulse critical line
(with no margin)
C: Effective pulse recommended
critical line (with margin)
Appendix
Appendix1-Rev1.1
The products listed in this document are designed to be used with ordinary electronic equipment or devices
(such as audio visual equipment, office-automation equipment, communications devices, electrical
appliances and electronic toys).
Should you intend to use these products with equipment or devices which require an extremely high level of
reliability and the malfunction of with would directly endanger human life (such as medical instruments,
transportation equipment, aerospace machinery, nuclear-reactor controllers, fuel controllers and other
safety devices), please be sure to consult with our sales representative in advance.
Notes
No technical content pages of this document may be reproduced in any form or transmitted by any
means without prior permission of ROHM CO.,LTD.
The contents described herein are subject to change without notice. The specifications for the
product described in this document are for reference only. Upon actual use, therefore, please request
that specifications to be separately delivered.
Application circuit diagrams and circuit constants contained herein are shown as examples of standard
use and operation. Please pay careful attention to the peripheral conditions when designing circuits
and deciding upon circuit constants in the set.
Any data, including, but not limited to application circuit diagrams information, described herein
are intended only as illustrations of such devices and not as the specifications for such devices. ROHM
CO.,LTD. disclaims any warranty that any use of such devices shall be free from infringement of any
third party's intellectual property rights or other proprietary rights, and further, assumes no liability of
whatsoever nature in the event of any such infringement, or arising from or connected with or related
to the use of such devices.
Upon the sale of any such devices, other than for buyer's right to use such devices itself, resell or
otherwise dispose of the same, no express or implied right or license to practice or commercially
exploit any intellectual property rights or other proprietary rights owned or controlled by
ROHM CO., LTD. is granted to any such buyer.
Products listed in this document are no antiradiation design.
About Export Control Order in Japan
Products described herein are the objects of controlled goods in Annex 1 (Item 16) of Export Trade Control
Order in Japan.
In case of export from Japan, please confirm if it applies to "objective" criteria or an "informed" (by MITI clause)
on the basis of "catch all controls for Non-Proliferation of Weapons of Mass Destruction.
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