by What are TVS Diodes?
Transient voltage suppressor diodes are semiconductor devices designed to protect electronic circuits from voltage spikes and power surges. They act as a surge absorption mechanism, diverting excess voltage to ground and shielding sensitive components from potential damage. TVS diodes have a breakdown voltage above the normal operating voltage of a circuit and begin conducting current when that voltage is exceeded, thus clamping the input voltage at a safe level.
Construction and Working
A TVS diode contains a PN junction fabricated from silicon materials like silicon carbide or gallium nitride. When the voltage across the junction exceeds its rating, the diode undergoes avalanche breakdown and starts conducting in the forward direction. This lowers the resistance across the diode and redirects surge current away from vulnerable components towards ground. The breakdown voltage of a Transient Voltage Suppressor Diodes is precisely engineered to activate only during transient spikes and not during regular circuit operation. They are specified to react within picoseconds or nanoseconds to effectively safeguard electronics.
Applications in Electronics
Some common applications of TVS diodes include protecting data lines, power lines, communications interfaces and inputs/outputs of electronic devices:
– In computers and servers, they are used to shield internal components and bus lines from induced voltage spikes through power cables, network cables or peripheral connections.
– In industrial equipment, TVS arrays provide multi-layer protection for sensitive analog/digital signals as well as 24V DC power circuits prone to transient disturbances.
– For telecom systems, they ensure surge immunity on telephone lines and maintain quality of voice/data transmission over long cable runs.
– In automotive electronics, TVS diodes help sustain functionality of engine control units, infotainment systems and safety devices even during sustained load dump events.
– For household appliances, they safeguard sensitive microcontroller boards, motors and displays from lightning strikes conducting through the power supply.
Operating Parameters to Consider
For effective protection, careful consideration must be given to the technical characteristics of TVS diodes used in a design:
– Breakdown (clamping) voltage – Must exceed maximum operating voltage but remain lower than stress levels of downstream devices.
– Response time – Critical parameter for high speed data lines where sub-ns triggering is essential to divert incoming surges.
– Current handling capability – Should far surpass maximum load current to avoid saturation during severe transients.
– Packaging – SOD-323, SMC, ESD packages best for board-level installation vs bigger DO-214 for rack-mount solutions.
– Series resistance – Low values help minimize voltage drop under normal circuit load.
Specifying the right TVS for an application with the correct voltage and power ratings goes a long way towards achieving robust surge immunity and reliability.
Standards and Testing
Industry standards like IEC 61000-4-2, -4-4 and -4-5 and UL 1449 provide guidelines for testing TVS performance attributes like clamping characteristics, power dissipation, failure mechanisms and life expectancy factors. Surge generators recreate typical fast/slow overvoltage waveforms to evaluate a device’s response. Parameters such as maximum clamping voltage, leakage current, energy suppression and failure threshold are recorded. Certification to relevant standards gives OEMs assurance of TVS quality and consistency across manufacturing batches.
Regular design reviews should analyze surge immunity requirements while factoring in expected lightning/EMI levels. Coordination with suppliers regarding available TVS options, SPICE models and ESD application notes helps select components appropriately for reliable surge protection. Return loss and insertion loss characteristics become important as data transmission speeds increase.
With the growing use of electronics in more hostile environments, it is critical to account for the threat of voltage transients during design stages itself. Transient voltage suppressor diodes provide robust, cost-effective solutions to prevent equipment damage and downtime from power surges. Their fast response characteristics coupled with precision engineering delivers optimum overvoltage protection according to application needs. Proper TVS selection backed by rigorous agency approvals and vendor engineering support paves the way for designing equipments with heightened reliability and dependability.
*Note:
1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it.
