The Infineon TT121N18KOF is a dual thyristor (SCR) power module rated for 121A average on-state current and a peak repetitive off-state voltage (VDRM/VRRM) of 1800V. Housed in a robust industry-standard module package, it integrates two thyristors in a common-cathode or inverse-parallel configuration suitable for fully controlled rectifier and AC controller topologies. The module's isolated baseplate construction simplifies heatsink mounting and meets the electrical isolation requirements common in industrial power conversion equipment operating at high bus voltages.

The TT121N18KOF is engineered for heavy-duty industrial applications where precise phase-angle control and high blocking voltage are essential. Typical deployments include three-phase soft starters, AC motor drives, static VAR compensators, resistance welding controllers, induction heating systems, and DC motor speed controllers in steel mills, mining equipment, marine propulsion drives, and large HVAC systems. Its high voltage rating makes it particularly well suited for medium-voltage grid-tied converters and legacy variable-speed drive platforms that remain in continuous service across process industries.

Quick Reference: TT121N18KOF

Key Features of the TT121N18KOF:

• 1800V repetitive peak off-state voltage (VDRM/VRRM) for high-voltage AC and DC bus applications
• 121A average on-state current (IT(AV)) supporting continuous high-power phase control duty cycles
• Low on-state voltage drop (VT) minimizing conduction losses and reducing heatsink thermal requirements
• Isolated copper baseplate for direct heatsink mounting with full electrical isolation from the thermal path
• High surge current capability (ITSM) providing resilience against transient overload conditions in motor start and fault scenarios
• Gate trigger characteristics optimized for compatibility with standard SCR firing boards and digital control platforms used in legacy and modern drive systems

With a factory lead time of 99 weeks on new production, the TT121N18KOF presents a serious procurement challenge for facilities managing unplanned equipment failures or scheduled maintenance outages. Extended waits at that scale are operationally unacceptable in continuous-process industries. ATI Accurate Technology maintains inventory of hard-to-find and long-lead-time thyristor modules precisely for these situations. Whether you need a single replacement module to return a drive to service today or are building safety stock for a multi-site maintenance program, ATI's in-stock position eliminates the supply chain uncertainty that a 99-week lead time creates.

ATI Accurate Technology is a specialized power semiconductor distributor located in Palmetto, Florida. We stock IGBTs, thyristors, diodes, and rectifier modules — including obsolete and long-lead-time parts — and ship same-day on orders placed before 5PM EST. Contact our technical sales team for volume pricing, cross-reference assistance, or application questions: 239-734-7566 | sales@igbts.us.