Product Description
The MZ9 series PTC thermistor is a miniature positive temperature coefficient (PTC) thermistor designed specifically for communication and signal line protection. Its core function is to provide overcurrent and overtemperature protection for sensitive communication interfaces, preventing damage to data ports caused by unexpected events such as hot plugging, voltage transients, cable shorts, and miswiring. By rapidly responding to abnormal currents and operating, it ensures the integrity of data transmission and the security of expensive back-end chipsets, making it an indispensable circuit protection component in communication equipment.
Specification
Product Name: MZ9 PTC Thermistor
R25 : 30-60Ω±25%
Diameter : 9mm
Non-action current : 83±7℃
Max voltage : 450V
Application : Communication interfaces
Color : Green or Yellow








Features
Fast Response and Self-Recovery: When an abnormal overcurrent condition occurs, it rapidly transitions from a low-resistance state to a high-resistance state ("action"), effectively limiting current. After the fault is resolved, it automatically cools down and returns to the low-resistance state, eliminating the need for manual replacement, significantly improving device maintainability and continuity.
Low Initial Resistance: Its extremely low initial resistance (typically in the milliohm range) minimizes signal attenuation, preventing interference with data transmission or degradation of signal quality.
Compact Design: Its compact size meets the trend toward miniaturization and integration in modern communications equipment.
High Voltage Withstand: It can withstand the high voltage surges that can occur in communications environments, providing robust protection for equipment.
High Reliability: Utilizing a ceramic semiconductor process, it offers long life, stable performance, and the ability to withstand multiple fault protection cycles.
Application
MZ9 PTC thermistors are widely used in various communications and electronic devices requiring reliable port protection:
Wired communication interfaces:
Protection of RS-232/RS-485/RS-422 interface chips
Industrial fieldbus ports such as CAN bus and Profibus
Ethernet ports (such as RJ45)
Phone lines (POTS) and xDSL modems
Computers and servers:
USB ports (especially industrial-grade USB)
Serial and parallel ports
Server backplane management interfaces
Consumer electronics and security:
Control and data interfaces for monitoring equipment
Network switches, routers, gateways, and other network devices
Industrial and automotive electronics:
Onboard diagnostic (OBD) interfaces
Various I/O interfaces for industrial controllers











