MCR25DG

Overview

The Littelfuse MCR25DG is a Silicon Controlled Rectifier (SCR) housed in a TO-220AB package. It features a peak repetitive off-state voltage of 400 V and an on-state RMS current rating of 25 A at a case temperature of 80°C. The device supports a peak non-repetitive surge current of 300 A and operates within a junction temperature range of -40°C to 125°C. Electrical characteristics include a maximum gate trigger current of 30 mA, a holding current of 40 mA, and a critical rate of rise of off-state voltage of 100 V/µs at 125°C.

Feature Summary

• Designed for half-wave AC control applications including motor controls, heating controls, and power supplies.
• Features glass passivated junctions to ensure reliability and uniformity under stress.
• Specified with minimum and maximum values for gate trigger current, gate trigger voltage, and holding current to facilitate circuit design.
• Provides high immunity to dv/dt with a minimum rating of 100 V/µsec at 125°C.

Applications

• Half-wave AC control circuits
• Motor controls
• Heating controls
• Power supplies

Procurement Notes

Verify the specific part number suffix against official Littelfuse documentation to confirm the exact blocking voltage rating. The 'DG' designation corresponds to a 400 V rating, while other suffixes like 'MG' or 'NG' indicate different voltage levels. Ensure that thermal management requirements align with the specified junction-to-case thermal resistance and derating curves provided in the datasheet before finalizing procurement specifications.

Selection Notes

Select the MCR25DG when a 400 V blocking voltage is required for half-wave rectification or AC control tasks. Compare the 25 A RMS current capability against the expected load profile, applying appropriate derating factors based on the operating case temperature. Verify that the gate drive circuit can supply sufficient current to exceed the 30 mA maximum trigger threshold reliably across the full operating temperature range.

Part Context

The MCR25DG belongs to the MCR25 series of silicon-controlled rectifiers manufactured by Littelfuse. This series includes variants with different voltage ratings, specifically the MCR25MG rated at 600 V and the MCR25NG rated at 800 V. All variants share the same TO-220AB package and 25 A RMS current rating, differing primarily in their peak repetitive off-state voltage capabilities.

Replacement Considerations

Direct replacements must match the 400 V blocking voltage, 25 A RMS current, and TO-220AB package. Verify that substitute devices meet or exceed the 300 A surge current rating and the 100 V/µs dv/dt specification. Check compatibility with the required gate trigger parameters and thermal resistance values.