Diodes Incorporated 1N4937-T

Overview

1N4937-T from Diodes Incorporated is a 1.0A fast recovery rectifier diode in DO-41 package, rated for 600V peak repetitive reverse voltage (VRRM), 1.2V forward voltage drop at 1.0A, and 200ns reverse recovery time - deployed in AC/DC front-end rectification for industrial power supplies and LED drivers.

For engineers reviewing the 1N4937-T datasheet, 1N4937-T pinout, 1N4937-T application, or 1N4937-T equivalent, key selection criteria include VRRM rating, IF(AV) derating behavior above +75°C, tRR performance under 0.5A–1A switching conditions, and DO-41 thermal resistance (RθJA = 100°C/W) in PCB-mounted configurations.

Technical Context

This discrete silicon PN junction diode uses diffused junction technology to achieve fast recovery with low stored charge, enabling efficient operation in 50/60Hz and higher-frequency switching power supplies up to ~20kHz. Its 30A non-repetitive surge rating supports inrush current handling during cold-start conditions.

Reverse leakage remains ≤5.0μA at 25°C and ≤100μA at 100°C under full DC blocking voltage (600V), ensuring stable high-voltage hold-off in standby and light-load modes. Total capacitance is 15pF at 4V reverse bias and 1MHz, minimizing high-frequency coupling in snubberless designs.

Key Specifications

Pinout & Package

Package: DO-41 molded plastic case (UL 94V-0), cathode indicated by band, axial leads plated with bright tin, weight ≈0.35g.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar fast recovery rectifier applications.

Compared with RS1J-E3/54, 1N4937-T delivers 2.5× faster recovery and 0.1V lower VFM - critical for EMI-sensitive LED drivers; versus 1N4937G, it offers identical performance with different plating process and traceability chain.

Availability

1N4937-T is available at Aetrix Electronics and suitable for industrial power adapters, LED lighting drivers, and UPS auxiliary supplies requiring stable component supply, long-term manufacturability, and RoHS-compliant sourcing.

Supply support for 1N4937-T includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, with design and manufacturing operations across Asia and the US.

The 1N4933–1N4937 series belongs to Diodes' general-purpose fast recovery rectifier product line, engineered for cost-effective, high-reliability AC/DC conversion in consumer, industrial, and lighting applications.

FAQ

What is the maximum ambient temperature for continuous 1.0A operation?

The 1N4937-T sustains 1.0A average forward current only up to +75°C ambient, as specified in the derating curve. Above that, current must be linearly reduced - e.g., to 0.7A at +100°C - due to thermal limitations of the DO-41 package (RθJA = 100°C/W) and silicon junction temperature limit of +150°C.

Can 1N4937-T replace a 1N4007 in a 60Hz power supply?

Yes, but with trade-offs: 1N4937-T offers faster recovery (200ns vs. 30μs) and lower VFM (1.2V vs. 1.1V), reducing switching loss and EMI. However, its 600V VRRM matches 1N4007's rating, so voltage capability is equivalent. Use is justified where efficiency or noise matters more than cost.

Is the DO-41 package suitable for automated pick-and-place assembly?

No - the axial DO-41 package is not compatible with standard SMT pick-and-place equipment. It requires through-hole insertion and wave or selective soldering. For automated assembly, consider surface-mount alternatives like the SMBF160 (600V, 1A) or SMA package equivalents.

Does 1N4937-T require a heatsink in typical applications?

Not typically: at 1.0A and 1.2V VFM, power dissipation is ~1.2W. With RθJA = 100°C/W and +25°C ambient, junction temperature rises to ~145°C - within the +150°C limit. Heatsinking becomes necessary only if ambient exceeds +50°C or if sustained operation near full rating is required in enclosed spaces.