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Positive Temperature Coefficient Thermistor For Telecom Over-current Protection

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Positive Temperature Coefficient Thermistor For Telecom Over-current Protection

Country/Region	china
City & Province	dongguan guangdong
Categories	Solar Lamps

Product Details

Positive Temperature Coefficient Thermistor For Telecom Over-current Protection

Quick Details

Compliant with ITU-T K20 K21 K45

--Basic level lightning surges (10/700μs)
--Basic level power Induction (600V,1A,0.2S)
--Power contact criteria A/B (230V,15min.)

Suitable for continuous connection to main voltage 110/230 VAC in tripped (high ohmic) condition.
Round leadless disk thermistor availble for combined usage of PTC and primary protection, e.g gas arrestor.
Typical Resistance @25C (R25) 10 ohm, 12 ohm, 18 ohm, 20 ohm, 25 ohm, 50 ohm, 55 ohm.
Matching available with narrow resistance tolerance.
Tight resistance tolerance maintained after switching.
Negligible resistance drift after soldering or switching.

Description

This series of ceramic PTC (positive temperature coefficient ) thermistors help provide protection against power cross, power induction surges and lighting surge defined in ITU, Telcordia, UL. Available in chip, radial-leaded coated and non-coated, SMD, twin vertical surface mount configuration. PTC thermistor overcurrent protector provides reversible, self-resetting protection against over-currents of telecommunication line protector units, improve the reliability of custom premises and network equipment.
Ceramic PTC thermistors can be found providing re-settable line protection at the exchange, monitoring hot spots and protecting ringers, battery feeds, transformers and relay circuits. Also used extensively to protect the mobile phone's battery pack against overcharging in land-based and radio mobile communications.

Advanced developments in telecom equipment in recent years have radically altered the protection requirements of both exchange and subscriber equipment. The PTC thermistor must protect the telephone line circuit against overcurrent, which may be caused by the following examples:
Surges due to lighting strikes on or near to the line plant.
Short-term induction of alternating voltage from adjactent power lines or railway systems, usually caused when these lines or systems develop faults
Direct contact between telephone lines and power lines.
To provide good protection under such conditions, a PTC thermistor is connected in series with each line, usually as secondary protection; However, even with primary line protection (usually a gas discharge tube), the PTC thermistor must fulfill severe requirements.
Surge pulses of upto 2KV can occur and in order to withstand short term power induction, the PTC thermistor must withstand high voltages. If the line has primary protection, a 220V to 300V PTC thermistor is adequate. Without primary protection, 600V PTC device is necessary. We can manufacture a series of PTC thermistor fulfilling both requirements.

Application

It's applicable to various types of fluorescent lamp, electronic ballast and electronic energy-saving lamp. The PTC can be connected across the lamp resonator without changing the circuits. It can change hard start of the ballast and electronic energy-saving lamp to preheated start and the preheating time of the filament can come up to 0.4-2 seconds, which will extend the service life of the fluorescent tube by over 4 times.

Specification

Typical Application of PTC Thermistor in Telecommunication Protection

Central Office Switching Equipment (C.O): analog and digital line cards, POTS, T1/E1 equipment, xDSL modems and splitters, multiplexers, CSU/DSU, servers.
Primary Protection Modules: MDF (main distribution frame) modules, network interface devices (NIC).
Custom Premises Equipment, also known as subscriber terminal equipment (T.E.), IT equipment: Modem, phone sets, fax machines, phone wall outlet (plugs), alarm systems, answering machine, PBX systems, ADSL Splitters, internet appliance, POS terminals.
Access Network hardware, LAN WAN equipment, Powered Ethernet systems, VoIP (voice over IP equipment), integrated voice data (IVD), Set-top box (S.B), etc.

Telecom PTC Thermistor Features

Compliant with ITU-T K20 K21 K45

--Basic level lightning surges (10/700μs)
--Basic level power Induction (600V,1A,0.2S)
--Power contact criteria A/B (230V,15min.)

PTC Thermistors Electrical Performances

Rated zero-power Resistance(R25)
Operating temperature range: 25±2℃, Within the allowable tolerance.

Non-operating characteristic
Operating temperature range: 40±2℃. In static air for 30min.Max. voltage: 60VDC. Non-operating current. Energized time: 60min. (R-R25)/R25≤50%

Over-current operating characteristic
Operating temperature range: 25±2℃,Max. voltage of power supply: 220Vrms.Test the time for the current decrease to limited value. See the spec. Table.

Over voltage withstanding (Power line contact)
Voltage of power supply: 250VAC, Initial current: 3A,Energized time: 30min . Restore time in room temperature is 4 hours, then test the R25. ΔR/R25≤20%.

Over current withstanding
Max. voltage of supply: 220VAC, Initial current: 3A. ON 60S, OFF 600S,Cycle:30 times, Restore time in room temperature is 4 hours, then re-test the Rn.
ΔR/Rn≤20%.

Surge current withstanding
Current waves: 10/1000μS, Minimum opening circuit voltage: 1.0kv, Peak current: 25A, Interval: 3min, Cycle:30 times, Restore time in room temperature is 4 hours, then re-test the R25. ΔR/R25≤20%.

Induction voltage current withstanding (Only for maximum voltage more than 600V)
Max. voltage of supply: 650VAC, Initial current: 1.1A.,ON 60S, OFF 600S,Cycle:10 times, Restore time in room temperature is 4 hours, then re-test the R25. ΔR/R25≤20%.

Fail Model
I. Voltage of power supply: 250VAC. Initial current: 10Arms,
II. Voltage of power supply: 600VAC. Initial current: 15Arms.
III. Voltage of power supply: 650VAC. Initial current: 10Arms.
Energized time: 30min. High resistance or open circuit is allowable. Low resistance state or firing is not allowed..

Restore time
The necessary time of a PTC to return to twice of R25. ≤60S.

Telecom PTC Thermistor Outline and Dimensions (unit:mm)

Fig.1	Fig.2	Fig.3	Fig.4

Fig.5

PTC Thermistor for Telecom Line Card Protection Application

Part number	Resistance @25C R₂₅ (Ohm)	Non-trip current Int(mA)		Trip current @25C It (mA)	Tripping time at max current (Sec)	Max. current I_max (A)	Max. voltage V_max (V)	Fail model	Dimension (mm)
Part number	Resistance @25C R₂₅ (Ohm)	@25C	@40C	Trip current @25C It (mA)	Tripping time at max current (Sec)	Max. current I_max (A)	Max. voltage V_max (V)	Fail model	D_max	T_max	Φd
MZ23-10RM130	10 ohm	130mA	100mA	260mA	<0.2s	1.0A	250V	250V/10A	7.5	4.0	0.6
MZ23-10RM150	10 ohm	150mA	100mA	260mA	<0.3s	2.0A	250V	250V/10A	9.0	5.0	0.6
MZ23-12RM130	12 ohm	130mA	100mA	260mA	<0.3s	2.0A	250V	250V/10A	9.0	5.0	0.6
MZ23-12RM090	12 ohm	90mA	60mA	160mA	<0.2s	2.0A	250V	250V/10A	9.0	5.0	0.6
MZ23-20RM100	20 ohm	100mA	80mA	200mA	<0.2s	3.0A	250V	250V/10A	9.0	4.0	0.6
MZ23-35RM090	35 ohm	90mA	75mA	180mA	<0.2s	3.0A	250V	250V/5A	9.0	5.0	0.6
MZ23-40RM080	40 ohm	80mA	70mA	160mA	<0.2s	3.0A	250V	250V/5A	9.0	5.0	0.6
MZ23-50RM070	50 ohm	70mA	60mA	150mA	<0.2s	3.0A	250V	250V/5A	9.0	5.0	0.6
MZ23-50RM075	50 ohm	75mA	60mA	150mA	<0.2s	3.0A	650V	650V/10A	9.5	5.0	0.6
MZ23-55RM070	55 ohm	70mA	60mA	150mA	<0.2s	3.0A	650V	650V/10A	9.5	5.0	0.6
MZ25-9R0M160	9 ohm	160mA	130mA	330mA	<0.8s	3.0A	250V	250V/10A	10.5	4.5	0.6
MZ25-25RM100	25 ohm	100mA	80mA	220mA	<0.2s	3.0A	250V	250V/10A	6.6	4.0	0.6
MZ25-25RM120	25 ohm	120mA	100mA	300mA	<0.4s	3.0A	250V	250V/10A	8.2	4.0	0.6
MZ26-10RM180SMD	10 ohm	180mA	140mA	360mA	<5.0s	1.0A	250V	250V/10A	/	/	/
MZ26-25RM130SMD	25 ohm	130mA	100mA	270mA	<0.3s	3.0A	250V	250V/10A	/	/	/
MZ26-50RM090SMD	50 ohm	90mA	70mA	190mA	<0.2s	3.0A	250V	250V/5A	/	/	/
MZ26-20RM100SMD	20 ohm	100mA	80mA	200mA	<0.2s	3.0A	250V	250V/10A	/	/	/

Note: Standard Resistance @25C (R25) allowable tolerance +/-20%, if not specified.

PTC Thermistor for Telecom MDF (Main Distribution Frame) Protection Application

Part number	Resistance @25C R₂₅ (Ohm)	Non-trip current Int (mA)		Trip current @25C It (mA)	Tripping time at max current (Sec)	Max. current I_max (A)	Max. voltage V_max (V)	Dimension (mm)
Part number	Resistance @25C R₂₅ (Ohm)	@25C	@40C	Trip current @25C It (mA)	Tripping time at max current (Sec)	Max. current I_max (A)	Max. voltage V_max (V)	D_max	T_max	Φd
MZ21-18RM110	18 ohm	110mA	90mA	220mA	<0.15s	3A	250V	5.5	1.5	/
MZ21-18RM125	18 ohm	125mA	110mA	250mA	<0.18s	3A	250V	5.5	2.0	/
MZ21-18RM130	18 ohm	130mA	110mA	260mA	<0.18s	3A	250V	6.2	2.0	/
MZ21-20RM085	20 ohm	85mA	70mA	170mA	<0.18s	3A	250V	6.2	2.0	/
MZ21-18RM135	18 ohm	135mA	110mA	270mA	<0.2s	3A	250V	6.6	2.0	/
MZ21-10RM150	10 ohm	150mA	130mA	350mA	<4.0s	3A	230V	7.2	1.5	/
MZ25-25RM055	25 ohm	55mA	45mA	110mA	<0.4s	1A	230V	5.3	4.0	0.6
MZ25-25RM060	25 ohm	60mA	50mA	120mA	<0.4s	1A	230V	5.3	4.0	0.6
MZ25-20RM145	20 ohm	145mA	100mA	250mA	<0.2s	3A	250V	6.6	4.0	0.6
MZ25-10RM130	10 ohm	130mA	110mA	260mA	<4.0s	1A	230V	6.6	4.0	0.6
MZ25-10RM150	10 ohm	150mA	135mA	300mA	<7.0s	1A	230V	8.2	4.0	0.6
MZ25-18RM125	18 ohm	125mA	110mA	250mA	<1.0s	1A	230V	5.5	4.0	0.6
MZ23-18RM135	18 ohm	135mA	110mA	270mA	<0.2s	3A	250V	7.5	4.5	0.6
MZ23-18RM110	18 ohm	110mA	90mA	220mA	<0.2s	3A	250V	9.0	4.5	0.6
MZ23-20RM100	20 ohm	100mA	80mA	200mA	<0.2s	3A	250V	9.0	4.5	0.6
MZ23-25RM085	25 ohm	85mA	75mA	170mA	<0.7s	1A	230V	6.5	5.0	0.6
MZ23-25RM090	25 ohm	90mA	70mA	180mA	<0.2s	3A	250V	9.0	4.5	0.6