SimSurfing
PTC Thermistor
Performance Simulator
Operation Manual

March, 2020
Murata ManufacturingCo., Ltd.
10 April 2020

1

Copyright © Murata Manufacturing Co., Ltd. All rights reserved.

10 April 2020

Contents
Page

1. About This Software
1-1. Overview
1-2. Main Functions
2. Quick Operation Guide
2-1. Operation Screen Description
2-2. Input simulation condition
2-3. Specification Confirmationof the Selected PTC Thermistor
2-4. PTC Thermistor Property Diagram
2-5. Confirm Simulation Result
3. Software Use Examples
3-1. Heating Detection Circuit Example Using PTC
3-2. Design of 130℃ Heating Detection Circuit
3-3. Confirming Circuit Conditions
3-4. Confirm PTC Specifications
3-5. Confirm Simulation Result
3-6. Change Fixed Resistance R1
3-7. Relationship Between Fixed Resistance R1 and Vth
3-8. Optimization of Circuits
4.Appendix
4-1. Specifications of the PRF Series
4-2. Standard Numerical Table

3
4
6
7
8
9
10

13
14
15
16
17
18
19
20
22
24

Copyright © Murata Manufacturing Co., Ltd. All rights reserved.

10 April 2020

2

1. About This Software
1-1. Overview
The “Chip PTC Thermistor Output Voltage Simulator” is a software that simulates output voltage temperature properties of the PTC thermistor (PRF series) for overheat detection.
Please use it to select PTC thermistors optimal for the specified overheat detection and circuit design
settings.

Operating Environment
Display Resolution: 1280×960 or more
OS: Microsoft Windows7 or higher, OS X 10.11 or higher
Browser: Internet Explorer 11, latest version of Microsoft Edge, latest version of Safari, latest
version of Google Chrome, latest version of Firefox*Microsoft, Windows, Internet Explorer, and Microsoft Edge aretrademarks of Microsoft Corporation.
*OS X and Safari are trademarks of Apple Inc.
*Google Chrome is a registered trademark of Google Inc.
*Mozilla and Firefox are trademarks of Mozilla Foundation in the
United States.
Copyright © Murata Manufacturing Co., Ltd. All rights reserved.

10 April 20203

1. About This Software
1-2. Main Functions

This simulator is a software that simulates how the output voltage Vout changes following ambient
temperature changes if the fixed resistance R1 and PTC thermistors are connected serially on voltage
Vcc circuits as indicated in diagram 1.

The main functions of this simulator are indicated below.
- You can select the PTC thermistor part number and amount of serially connected PTC thermistors to
the circuit from 1 - 100. However, only 1 PTC thermistor can be installed.

- Enables simulation of the output voltage - temperature properties of the PTC thermistor used to detect
the temperature in the -40℃ - +160℃ range.
- Enables setting of the power voltage (Vcc), deviation, and temperature dependence of the circuit onwhich the PTC thermistor is installed.
- Enables setting of the resistance values, deviation, and temperature dependence of the fixedresistance (R1) used as voltage dividing resistance.

Diagram 1 Circuit Diagram

Copyright © Murata Manufacturing Co., Ltd. All rights reserved.

10 April 2020

4

Contents
Page

1. About This Software
1-1. Overview
1-2. Main Functions
2. Quick Operation Guide
2-1. Operation Screen Description
2-2. Input simulation condition
2-3. Specification Confirmationof the Selected PTC Thermistor
2-4. PTC Thermistor Property Diagram
2-5. Confirm Simulation Result
3. Software Use Examples
3-1. Heating Detection Circuit Example Using PTC
3-2. Design of 130℃ Heating Detection Circuit
3-3. Confirming Circuit Conditions
3-4. Confirm PTC Specifications
3-5. Confirm Simulation Result
3-6. Change Fixed Resistance R1
3-7. Relationship Between Fixed Resistance R1 and Vth
3-8. Optimization of Circuits
4.Appendix
4-1. Specifications of the PRF Series
4-2. Standard Numerical Table

3
4
6
7
8
9
10

13
14
15
16
17
18
19
20
22
24

Copyright © Murata Manufacturing Co., Ltd. All rights reserved.

10 April 2020

5

2. Quick Operation Guide
2-1. Operation Screen Description
Description of the operation screen
Only the areas marked with blue frames in diagram 2 are areas where input is required. Areas marked
with red frames are where selected PTC part number information and calculation results areautomatically displayed.
4) Press the start simulation button

1) Input simulation condition

1)Input simulation condition

2) Select part number of the PTC thermistor

2)Select part number of the PTC thermistor

3) Confirm the specification of
the selected part number
4) Press the start simulation button5) Confirm the simulation result

Diagram 2 Simulation Operation Screen3) Confirm the specification of the selected part number5) Confirm the simulation result

Copyright © Murata Manufacturing Co., Ltd. All rights reserved.

10 April 2020

6

2. Quick Operation Guide
2-2. Input simulation condition<Input simulation condition>

PhraseTemp_H
Temp_L

Ambient Temp.
Number of PTC

Vcc

Vcc
Tolerance
TC VccR1

R1
Tolerance
TC R1

Detailed Description
Lower limit of the simulation temperature range.
Available for setting in -40℃ - 160℃.
Upper limit of the simulation temperature range.
Available for setting in 40℃ - 160℃.
Ambient temperature. Available for setting in
40℃ - 160℃.
Can be set with 1 - 100 serially connected PTC
thermistors.
Power voltage of the circuit
Deviation of the power voltage
Temperature dependence of the power voltage
Resistance value of the voltage dividing
resistance (fixed resistance) connected to the
PTC thermistor
Deviation of the fixed resistance
Temperature dependence of the fixed resistance

Copyright © Murata Manufacturing Co., Ltd. All rights reserved.

10 April 2020

7

2. Quick Operation Guide
2-3. Specification Confirmation of the Selected PTC
Thermistor< Specification of the Selected PTC Thermistor >PhrasePart Number

PTC Part
NumberR25

Detailed Description
Product name of the PTC thermistor used during the simulation.
The product name selected in the dialog box is displayed.
Resistance value when PTC thermistor is 25℃

Tolerance

Sensing
Temp.1

Deviation of the resistance value when PTC thermistor is 25℃
Detected Temperature 1
Sensing
When the PTC thermistor reaches the specified resistanceTemp.1value, indicates what temperature the element temperature
becomes.
Resistance Resistance value in Sensing Temp.1 (varies by part number)
Temp.

Center value of detected temperature 1

Tolerance

Sensing
Temp.2

Deviation for the center value of detected temperature 1
Detected temperature 2
Sensing
Only the PTC thermistor with 2 point guarantee of the detected
Temp.2temperature is displayed.
Resistance Resistance value in Sensing Temp.2 (varies by part number)
Temp.

Center value of detected temperature 2

Tolerance

Deviation for the center value of detected temperature 2

Copyright © Murata Manufacturing Co., Ltd. All rights reserved.

10 April 2020

8

2. Quick Operation Guide
2-4. PTC Thermistor Property Diagram

Copyright © Murata Manufacturing Co., Ltd. All rights reserved.

10 April 2020

9

2. Quick Operation Guide
2-5. Confirm Simulation Result< Confirm Simulation Result >Threshold
Voltage(Vth)Vd

Vth_Sensing1

Vout in Sensing Temp1

Vth_Sensing2

Vout in Sensing Temp2

Vd at Ambient
Temp.

Voltage difference of voltage Vout and Sensing
Temp (Vth) in a certain temperature T

Min

Smallest value of Vd at Ambient Temp

Max

Largest value of Vd at Ambient Temp

Sensing Temp. Temperature detection range when theat Vthdetected voltage is Vth

SensingTemp.
at VthMin

Smallest value of the aboveMax

Largest value of the above

Copyright © Murata Manufacturing Co., Ltd. All rights reserved.

10 April 202010

This is the end of the operation
manual. To enable maximum usageof the software, techniques anddetailed descriptions of operation
procedures will be introduced fromthe next page on.

11

Copyright © Murata Manufacturing Co., Ltd. All rights reserved.

10 April 2020

Contents
Page

1. About This Software
1-1. Overview
1-2. Main Functions
2. Quick Operation Guide
2-1. Operation Screen Description
2-2. Input simulation condition
2-3. Specification Confirmationof the Selected PTC Thermistor
2-4. PTC Thermistor Property Diagram
2-5. Confirm Simulation Result
3. Software Use Examples
3-1. Heating Detection Circuit Example Using PTC
3-2. Design of 130℃ Heating Detection Circuit
3-3. Confirming Circuit Conditions
3-4. Confirm PTC Specifications
3-5. Confirm Simulation Result
3-6. Change Fixed Resistance R1
3-7. Relationship Between Fixed Resistance R1 and Vth
3-8. Optimization of Circuits
4.Appendix
4-1. Specifications of the PRF Series
4-2. Standard Numerical Table

3
4
6
7
8
9
10

13
14
15
16
17
18
19
20
22
24

Copyright © Murata Manufacturing Co., Ltd. All rights reserved.

10 April 202012

3. Software Use Examples
3-1. Heating Detection Circuit Example Using PTC
Enables design of a circuit that detects heating of multiple FETs using the PRF series as
seen in the diagram below. Try the simulation using the following circuit as an example.

Vcc
Vout

R1

PRF

FET

PRF
Enables realization ofheating detection at
various points with 1 IC
port!

PRF
PRF
PRF

Copyright © Murata Manufacturing Co., Ltd. All rights reserved.

10 April 202013

3. Software Use Examples
3-2. Design of 130℃ Heating Detection Circuit- Design Example Thermistor used
:PRF18BB471QB#RB(Refer to the specification list in P22 - 23 for thermistor selection)
Circuit: right diagram(Voltage dividing resistance + 5 PTC thermistors)

Operating temperature range :-20℃～150℃
Normal ambient temperature：25℃
Input voltage Vin： 3V(assuming there are no voltage fluctuation)

Resistance R1： Adjustable following E24 step

Circuit Conditions ：To perform heating detection in the 130℃ range(the Vout is to fluctuate 1V between the normal state and heated state)

Copyright © Murata Manufacturing Co., Ltd. All rights reserved.

10 April 202014

3. Software Use Examples
3-3. Confirming Circuit Conditions
(3)
(1)

(2)

(1) Set Number of PTC to 5 pcs.
(Make adjustments later while observing simulation results for R1)(2) The used PTC part number is PRF18BB471QB#RB.
(3) Click Start Simulation and display the result.
Copyright © Murata Manufacturing Co., Ltd. All rights reserved.

10 April 202015

3. Software Use Examples
3-4. Confirm PTC Specifications

Confirm the PTC specification and confirm that the selection is correct. The selected
thermistor is used to detect 115±5℃ (Sensing Temp_1) or 130±7℃ (SensingTemp_2).
Circuit design will be performed using Temp_2 here. (Temp_1 has a small temperaturedeviation and Temp_2 has a large voltage fluctuation.)
Copyright © Murata Manufacturing Co., Ltd. All rights reserved.

10 April 202016

3. Software Use Examples
3-5. Confirm Simulation Result(123℃,1.5V)(137℃,1.5V)
1.428
1.289

25

Confirm simulation results in SensingTemp_2.
You can see that Vout reaches 1.5 V while the temperature is 123 - 137℃ in the item related toVth. Furthermore, in this simulation, you can see that Vd at ambient Temp indicates the changeof Vout in 25℃ and 150℃, and there is a large gain of over 1.2 V voltage change in input voltage
3 V.
Next, confirm the relationship between R1 and the simulation result.
Copyright © Murata Manufacturing Co., Ltd. All rights reserved.

10 April 202017

3. Software Use Examples
3-6. Change Fixed Resistance R1(123℃,1.5V)(137℃,1.5V)

Try the simulation again with R1 as 100 kohm.

Copyright © Murata Manufacturing Co., Ltd. All rights reserved.

10 April 202018

3. Software Use Examples
3-7. Relationship Between Fixed Resistance R1 and Vth

Vth_Sensing2(R1=47kohm)

Vth_Sensing1(R1=100kohm)

You can see that Vth = 1.5 V when R1 = 47 kohm and Vth = 0.96 V when R1 = 100 kohm.
Generally, making fixed resistance R1 larger will make Vth (Vout of detected temperature) smaller.
Enables setting of desired Vout based on the type of control IC. This design condition is “Voutfluctuates by 1 V between the normal state and when heated.” Therefore, R1 is changed again
and an optimal condition is searched for.

Copyright © Murata Manufacturing Co., Ltd. All rights reserved.

10 April 202019

3. Software Use Examples
3-8. Optimization of Circuits

By making R1 = 75 ohm, Vd at ambient Temp (Vout change in 25℃ - 130℃)
becomes 1.02 V - 1.11 V, and achieves your desired circuit.
Copyright © Murata Manufacturing Co., Ltd. All rights reserved.

10 April 202020

Contents
Page

1. About This Software
1-1. Overview
1-2. Main Functions
2. Quick Operation Guide
2-1. Operation Screen Description
2-2. Input simulation condition
2-3. Specification Confirmationof the Selected PTC Thermistor
2-4. PTC Thermistor Property Diagram
2-5. Confirm Simulation Result
3. Software Use Examples
3-1. Heating Detection Circuit Example Using PTC
3-2. Design of 130℃ Heating Detection Circuit
3-3. Confirming Circuit Conditions
3-4. Confirm PTC Specifications
3-5. Confirm Simulation Result
3-6. Change Fixed Resistance R1
3-7. Relationship Between Fixed Resistance R1 and Vth
3-8. Optimization of Circuits
4.Appendix
4-1. Specifications of the PRF Series
4-2. Standard Numerical Table

3
4
6
7
8
9
10

13
14
15
16
17
18
19
20
22
24

Copyright © Murata Manufacturing Co., Ltd. All rights reserved.

10 April 2020

21

4. Appendix
4-1. Specifications of the PRF Series (1/2)
No.

Item

R25
[Ω]

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25

PRF15AR102RB#RC
PRF15BA102RB#RC
PRF15BB102RB#RC
PRF15BC102RB#RC
PRF15BD102RB#RC
PRF15BE102RB#RC
PRF15BF102RB#RC
PRF15BG102RB#RC
PRF15BB103RB#RC
PRF15BE103RB#RC
PRF15BG103RB#RC
PRF18AS471QB#RB
PRF18AR471QB#RB
PRF18BA471QB#RB
PRF18BB471QB#RB
PRF18BC471QB#RB
PRF18BD471QB#RB
PRF18BE471QB#RB
PRF18BF471QB#RB
PRF18BG471QB#RB
PRF18BB471RB#RB
PRF18BC471RB#RB
PRF18BD471RB#RB
PRF18BE471RB#RB
PRF18BF471RB#RB

1000
1000
1000
1000
1000
1000
1000
1000
10000
10000
10000
470
470
470
470
470
470
470
470
470
470
470
470
470
470

Sensing
Sensing
Temperature 1
Temperature 2[%][°C]
Resistance Temp. Tolerance Resistance Temp. Tolerance(Typical)
[kΩ]
[°C]
[°C]
[kΩ]
[°C]
[°C]
50
120
10
135
5
100
150
3
50
110
10
125
5
100
140
3
50
100
10
115
5
100
130
3
50
90
10
105
5
100
120
3
50
80
10
95
5
100
110
3
50
70
10
85
5
100
100
3
50
60
10
75
5
100
90
3
50
50
10
65
5
100
80
3
50
102
4700
130
3
50
70
4700
100
3
50
50
4700
80
3
50
130
4.7
145
5
50
120
4.7
135
5
47
150
7
50
110
4.7
125
5
47
140
7
50
100
4.7
115
5
47
130
7
50
90
4.7
105
5
47
120
7
50
80
4.7
95
5
47
110
7
50
70
4.7
85
5
47
100
7
50
60
4.7
75
5
47
90
7
50
50
4.7
65
5
47
80
7
50
100
4.7
115
3
47
130
7
50
90
4.7
105
3
47
120
7
50
80
4.7
95
3
47
110
7
50
70
4.7
85
3
47
100
7
50
70
4.7
75
3
47
90
7

ToleranceCP

Copyright © Murata Manufacturing Co., Ltd. All rights reserved.

10 April 2020

22

4. Appendix
4-1. Specifications of the PRF Series (2/2)
No.

Item

R25
[Ω]

26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48

PRF18BG471RB#RB
PRF21AS471QB#RA
PRF21AR471QB#RA
PRF21BA471QB#RA
PRF21BB471QB#RA
PRF21BC471QB#RA
PRF21BD471QB#RA
PRF21BE471QB#RA
PRF18AS471QS#RB
PRF18AR471QS#RB
PRF18BA471QS#RB
PRF18BB471QS#RB
PRF18BC471QS#RB
PRF18BD471QS#RB
PRF18BE471QS#RB
PRF18BF471QS#RB
PRF18BG471QS#RB
PRF18BB471RS#RB
PRF18BC471RS#RB
PRF18BD471RS#RB
PRF18BE471RS#RB
PRF18BF471RS#RB
PRF18BG471RS#RB

470
470
470
470
470
470
470
470
470
470
470
470
470
470
470
470
470
470
470
470
470
470
470

Sensing
Sensing
Temperature 1
Temperature 2[%][°C]
Resistance Temp. Tolerance Resistance Temp. Tolerance(Typical)
[kΩ]
[°C]
[°C]
[kΩ]
[°C]
[°C]
50
70
4.7
65
3
47
80
7
50
130
4.7
145
5
50
120
4.7
135
5
50
110
4.7
125
5
50
100
4.7
115
5
50
90
4.7
105
5
50
80
4.7
95
5
50
70
4.7
85
5
50
130
4.7
145
5
50
120
4.7
135
5
47
150
7
50
110
4.7
125
5
47
140
7
50
100
4.7
115
5
47
130
7
50
90
4.7
105
5
47
120
7
50
80
4.7
95
5
47
110
7
50
70
4.7
85
5
47
100
7
50
60
4.7
75
5
47
90
7
50
50
4.7
65
5
47
80
7
50
100
4.7
115
3
47
130
7
50
90
4.7
105
3
47
120
7
50
80
4.7
95
3
47
110
7
50
70
4.7
85
3
47
100
7
50
70
4.7
75
3
47
90
7
50
70
4.7
65
3
47
80
7

ToleranceCP

Copyright © Murata Manufacturing Co., Ltd. All rights reserved.

10 April 2020

23

4. Appendix
4-2. Standard Numerical Table

Copyright © Murata Manufacturing Co., Ltd. All rights reserved.

10 April 202024