Inrush Current Limiting Power NTC Thermistors
Power NTC thermistor Description
Power NTC thermistor can be a cost effective device to limit the amount of inrush current in a switching power supply or other devices when the power is first turned on. Power NTC thermistor limits surge current by functioning as a power resistor which drops from a high cold resistance to a low hot resistance when heated by the current flowing through it.
Inrush-current limiters power NTC thermistor protect circuits from undesirably high currents, suppressing high inrush current surges, while its resistance remains negligible low during continuous operation. Thanks to their low resistance in the operating state, Power thermistor have a considerably lower power dissipation than the fixed resistors frequently used for this application.
Inrush Current Limiting Power NTC Thermistor Application
limiting surge current, suitable for the protection of switch mode power supply, UPS power, transformers, motors, various electric heating utensil, energy saving lights, ballast, various power circuit, amplifiers, colored displayer, monitors, color TV, filament protection, etc.
Power thermistor components can also be used for the soft starting of motors, for example in vacuum cleaners with continuous currents of up to 20 A.
Inrush Current Limiting Power NTC Thermistor Advantages:
¡¤Low cost solid state device for inrush current supression.
¡¤Minimise line current distortion and radio noise.
¡¤Protect switches, rectifier diodes and smoothing capacitors against premature failures.
¡¤Prevent fuse from blowing in error.
Inrush Current Limiting Power NTC Thermistor Features:
¡¤Resin coated disk thermistor with uninsulated lead-wires.
¡¤Suitable for both AC and DC circuits up to a voltage of 265 V(rms).
¡¤Wide range of resistance, current and dimension.
¡¤Excellent mechanical strength.
¡¤Suitable for PCB mounting.
Comparison curve with and without power NTC thermistor application |
Power NTC thermistor Load-temperature characteristics |
Typical Application of Inrush Current Limiting Power NTC thermistors for Circuit Protection
Inrush Current Limiting Power NTC Thermistors Dimensions (mm)
AMWEI Inrush Current Limiting Power NTC Thermistors Data Sheet
| Part No. |
R25(¦¸) |
Max Stable Current(A) |
Approx. Resistance Value at Maximum Current (¦¸) |
Dissipation Factor (mW/oC) |
Thermal Time Constant (s) |
Dimensions (mm) |
| Dmax |
Tmax |
H |
H 0 |
d¡À1 |
| AMF72-10D5 |
10 |
0.7 |
0.771 |
9 |
16 |
7 |
5 |
9.5 |
16.5 |
5/ 2.5 |
| AMF72-200D5 |
200 |
0.1 |
6.259 |
9 |
16 |
7 |
5 |
9.5 |
16.5 |
5/ 2.5 |
| AMF72-5D7 |
5 |
2 |
0.283 |
14 |
26 |
9 |
5 |
11.5 |
18.5 |
5 |
| AMF72-10D7 |
10 |
1 |
0.616 |
9 |
27 |
9 |
5 |
11.5 |
18.5 |
5 |
| AMF72-22D7 |
22 |
0.6 |
1.108 |
9 |
27 |
9 |
5 |
11.5 |
18.5 |
5 |
| AMF72-3D9 |
3 |
4 |
0.120 |
11 |
34 |
11 |
5.5 |
13.5 |
20.5 |
7.5 /5 |
| AMF72-5D9 |
5 |
3 |
0.210 |
11 |
34 |
11 |
5.5 |
13.5 |
20.5 |
7.5 /5 |
| AMF72-8D9 |
8 |
2 |
0.400 |
11 |
32 |
11 |
5.5 |
13.5 |
20.5 |
7.5 /5 |
| AMF72-10D9 |
10 |
2 |
0.458 |
11 |
32 |
11 |
5.5 |
13.5 |
20.5 |
7.5 /5 |
| AMF72-16D9 |
16 |
1 |
0.802 |
11 |
31 |
11 |
5.5 |
13.5 |
20.5 |
7.5 /5 |
| AMF72-22D9 |
22 |
1 |
0.950 |
11 |
30 |
11 |
5.5 |
13.5 |
20.5 |
7.5 /5 |
| AMF72-33D9 |
33 |
1 |
1.124 |
11 |
30 |
11 |
5.5 |
13.5 |
20.5 |
7.5 /5 |
| AMF72-50D9 |
50 |
1 |
1.252 |
11 |
30 |
11 |
5.5 |
13.5 |
20.5 |
7.5 /5 |
| AMF72-80D9 |
80 |
0.8 |
2.010 |
11 |
30 |
11 |
5.5 |
13.5 |
20.5 |
7.5 /5 |
| AMF72-3D11 |
3 |
5 |
0.100 |
13 |
43 |
13 |
5.5 |
15.5 |
22.5 |
7.5 /5 |
| AMF72-5D11 |
5 |
4 |
0.156 |
13 |
45 |
13 |
5.5 |
15.5 |
22.5 |
7.5 /5 |
| AMF72-8D11 |
8 |
3 |
0.255 |
14 |
47 |
13 |
5.5 |
15.5 |
22.5 |
7.5 /5 |
| AMF72-10D11 |
10 |
3 |
0.275 |
14 |
47 |
13 |
5.5 |
15.5 |
22.5 |
7.5 /5 |
| AMF72-16D11 |
16 |
2 |
0.470 |
14 |
50 |
13 |
5.5 |
15.5 |
22.5 |
7.5 /5 |
| AMF72-22D11 |
22 |
2 |
0.563 |
15 |
52 |
13 |
5.5 |
15.5 |
22.5 |
7.5 /5 |
| AMF72-33D11 |
33 |
1.5 |
0.734 |
15 |
52 |
13 |
5.5 |
15.5 |
22.5 |
7.5 /5 |
| AMF72-50D11 |
50 |
1.5 |
1.021 |
15 |
52 |
13 |
5.5 |
15.5 |
22.5 |
7.5 /5 |
| AMF72-60D11 |
60 |
1.5 |
1.215 |
15 |
52 |
13 |
5.5 |
15.5 |
22.5 |
7.5 /5 |
| AMF72-1.3D13 |
1.3 |
7 |
0.062 |
13 |
60 |
15.5 |
6 |
17.5 |
24.5 |
7.5 |
| AMF72-3D13 |
3 |
6 |
0.092 |
14 |
60 |
15.5 |
6 |
17.5 |
24.5 |
7.5 |
| AMF72-5D13 |
5 |
5 |
0.125 |
15 |
68 |
15.5 |
6 |
17.5 |
24.5 |
7.5 |
| AMF72-10D13 |
10 |
4 |
0.206 |
15 |
65 |
15.5 |
6 |
17.5 |
24.5 |
7.5 |
| AMF72-15D13 |
15 |
3 |
0.335 |
16 |
60 |
15.5 |
6 |
17.5 |
24.5 |
7.5 |
| AMF72-30D13 |
30 |
2.5 |
0.517 |
16 |
65 |
15.5 |
6 |
17.5 |
24.5 |
7.5 |
| AMF72-3D15 |
3 |
7 |
0.075 |
18 |
76 |
17.5 |
6 |
19.5 |
26.5 |
10/7.5 |
| AMF72-5D15 |
5 |
6 |
0.112 |
20 |
76 |
17.5 |
6 |
19.5 |
26.5 |
10/7.5 |
| AMF72-8D15 |
8 |
5 |
0.178 |
20 |
80 |
17.5 |
6 |
19.5 |
26.5 |
10/7.5 |
| AMF72-10D15 |
10 |
5 |
0.180 |
21 |
85 |
17.5 |
6 |
19.5 |
26.5 |
10/7.5 |
/tr>
| AMF72-15D15 |
15 |
4 |
0.268 |
20 |
75 |
17.5 |
6 |
19.5 |
26.5 |
10/7.5 |
| AMF72-30D15 |
30 |
3.5 |
0.438 |
18 |
75 |
17.5 |
6 |
19.5 |
26.5 |
10/7.5 |
| AMF72-47D15 |
47 |
3 |
0.680 |
21 |
86 |
17.5 |
6 |
19.5 |
26.5 |
10/7.5 |
| AMF72-0.7D20 |
0.7 |
12 |
0.018 |
25 |
89 |
22.5 |
7 |
24.5 |
31.5 |
10/7.5 |
| AMF72-1.3D20 |
1.3 |
9 |
0.037 |
24 |
88 |
22.5 |
7 |
24.5 |
31.5 |
10/7.5 |
| AMF72-3D20 |
3 |
8 |
0.055 |
24 |
88 |
22.5 |
7 |
24.5 |
31.5 |
10/7.5 |
| AMF72-5D20 |
5 |
7 |
0.087 |
23 |
87 |
22.5 |
7 |
24.5 |
31.5 |
10/7.5 |
| AMF72-8D20 |
8 |
6 |
0.142 |
25 |
105 |
22.5 |
7 |
24.5 |
31.5 |
10/7.5 |
| AMF72-10D20 |
10 |
6 |
0.162 |
24 |
102 |
22.5 |
7 |
24.5 |
31.5 |
10/7.5 |
| AMF72-0.7D25 |
0.7 |
13 |
0.014 |
30 |
120 |
27.5 |
8 |
\ |
\ |
10/7.5 |
| AMF72-1.5D25 |
1.5 |
10 |
0.027 |
30 |
121 |
27.5 |
8 |
\ |
\ |
10/7.5 |
| AMF72-3D25 |
3 |
9 |
0.044 |
32 |
124 |
27.5 |
8 |
\ |
\ |
10/7.5 |
| AMF72-5D25 |
5 |
8 |
0.070 |
32 |
125 |
27.5 |
8 |
\ |
\ |
10/7.5 |
Inrush Current Limiting Power NTC thermistor Reliability Data
Test |
Standard |
Test Conditions |
¦¤R25/R25 (typical) |
Remarks |
| Storage in dry heat |
IEC 60068-2-2 |
Storage at upper category temperature Temperature: 125oC Time: 1000h |
<10% |
No visible damage |
| Storage in damp heat, steady state |
IEC 60068-2-3 |
Temperature of air: 40oC Relative humidity of air: 93% Duration: 21 days |
<5% |
No visible damage |
| Rapid temperature cycling |
IEC 60068-2-14 |
Lower test temperature: -55oC Upper test temperature: 125oC Number of cycles: 10 |
<10% |
No visible damage |
| Endurance |
\ |
I=Imax t: 1000h |
<10% |
No visible damage |
| Cyclic endurance |
\ |
I=Imax, 1000 cycles On-time=1 min Cooling time=6 min |
<10% |
\ |
| Transient load |
\ |
Capacitance=CT Number of cycles: 1000 |
<5% |
No visible damage |
Reference information for selecting inrush current limiting power NTC thermistor
1) Maximum operating current > Actual operating current in the power loop
2) Rated zero power resistance at 25C
of which, E: loop voltage, Im: Surge current
For conversion power, reversion power, switch power, UPS power, Im=100 times operating current
For filament, heater, Im =30 times operating current
3) The larger B value, the smaller residual resistance, the smaller operating temperature rising.
4) Generally, the larger product of time constant and dissipation coefficient, the larger NTC thermal capacity, the more powerful NTC thermistor surge current restraining capacity.
Inrush Current Limiting Power NTC Thermistor Application Precautions
1) For inrush current limiting, the NTC thermistor must be connected in series with the load circuit. Several inrush current limiters can also be connected in series for higher damping. Inrush current limiters must not be connected in parallel.
2)
In general inrush current limiters require time to get back to cold state, in which they can provide adequate inrush current limiting due to their high resistance. The cooling down time depends on ambient conditions.
3)
It should be considered that the surrounding area of NTC Thermistor may become quite hot.
|
MAIN | 
Thermistors Search 
/ 
