Ceramic PTC Thermistor for Telecom High Voltage Current Surge Protection

Ceramic PTC Thermistor for Telecom High Voltage Current Surge Protection Description:

Ceramic positive temperature coefficient PTC thermistor 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 configuration.

This thermally sensitive semiconductor resistor provides reversible, self-resetting fuse protection against over-currents short circuit for telecommunication line protector units, improve the reliability of custom premises and network equipment.

PTC Thermistor Current Limiting Protection Device can be found providing resettable line protection at the exchange, monitoring hot spots and protecting ringers, battery feeds, transformers, switches 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. PTC Thermistor Current Protector 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 adjacent 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.

PTC Thermistor Application in Telecommunication Equipment

• 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.
• Landline telephones or FAX machines
• Telephone interface of STB, VoIP equipment
• Any other equipment of communication facility having a phone line interface

PTC Thermistors Telecom Application 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.)
• Suitable for continuous connection to main voltage 110/230 VAC in tripped (high ohmic) condition.
• Round leadless disk thermistor available for combined usage of PTC and primary protection, e.g gas arrestor.
• Thermistor disk coated non-coated construction, diameter 5mm to 10mm.
• 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.

More information on AMWEI PTC Thermistor for Telecom Over-current Protection  can be found in

https://amwei.com/ptc-thermistors/ptc-thermistor-high-voltage-current-surge-telecom-protect/