Ceramic PTC Thermistor for High Voltage Current Surge Protection

Ceramic positive temperature coefficient PTC 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 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 Thermistors 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.

High Voltage Current Surge Protection PTC Thermistor Application in Telecommunication Equipment

PTC Thermistor Current Protector 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 Overload Surge Current Protection Electrical Performances

PTC Thermistor Current Protector Outline and Dimensions (unit:mm)

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

PTC Thermistor for Telecom Line Card Protection Application

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

Typical telephone line showing where PTC thermistors can be used for overcurrent protection

An example of PTC Thermistors for telecom circuit protection