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TDK MT40 ThermoFuse Varistors

TDK MT40 ThermoFuse Varistors provide robust protection up to 50kA while minimizing size (38.0mm length x 15.2mm width x 40.9mm height). The MT40 series is commonly used in inverters, industrial power supplies, outdoor lighting, telecommunications systems, and surge protection devices (SPDs). These TDK ThermoFuse varistors are designed for extreme electrical conditions and have a peak surge current capability of up to 50kA (8/20μs pulse) and a short-circuit current rating of up to 200kA. The series is recognized as a UL 1449 Type 1CA component assembly, designed for applications with voltages ranging from 150VAC to 550VAC and 200VDC to 750VDC. 

Features

  • Strap-terminated varistor with a thermal disconnecting system
  • Compact size
  • Flame-retardant epoxy encapsulation
  • Up to 200kA short-circuit current rating (SCCR) according to UL 1449
  • Up to 50kA high peak surge current
  • UL 1449-recognized as a type 1CA for both AC and DC applications (file number E321126)
  • Normally open micro-switch for remote indication/monitoring circuit
  • Same electrode PCB footprint for all types
  • RoHS, REACH, and PFAS compliant

Applications

  • PV systems
  • Industrial power supplies
  • Outdoor lighting systems
  • Telecommunication systems
  • SPDs

Specifications

  • 40 / 85/ 56 climatic category to IEC 60068-1
  • -40°C to +85°C operating temperature range
  • <25ns response time
  • UL94-V0 (black color) coating material
  • IP20 ingress protection
  • ≥2500VAC electric strength
  • <5000m application altitude
  • Onboard installation

Typical Circuit Diagram

Application Circuit Diagram - TDK MT40 ThermoFuse Varistors

Dimensions (mm)

Mechanical Drawing - TDK MT40 ThermoFuse Varistors
Publicado: 2025-07-31 | Actualizado: 2026-04-10