Microchip Technology 1N4740E3/TR13

Overview

1N4740E3/TR13 from Microsemi is a 10 V, ±5% tolerance, 1 W silicon Zener diode in DO-41 plastic package, rated for 25 mA test current, 7 Ω dynamic impedance at I_ZT, and 91 mA maximum regulator current at T_A = 50°C. It provides stable voltage regulation in power supply reference and overvoltage protection circuits across industrial temperature range.

For engineers reviewing the 1N4740E3/TR13 datasheet, 1N4740E3/TR13 pinout, 1N4740E3/TR13 application, or 1N4740E3/TR13 equivalent, key selection criteria include Zener voltage accuracy, thermal resistance (45°C/W junction-to-lead), surge current rating (454 mA), RoHS-compliant matte-tin plating, and tape-and-reel packaging (TR13).

Technical Context

This device operates in reverse breakdown to maintain a stable 10 V reference across a wide current range (0.25–91 mA). Its Zener knee is characterized at 0.25 mA with 7 Ω impedance, ensuring low-noise regulation near threshold. The DO-41 package enables axial-leaded through-hole mounting with 0.7 g mass and UL94V-0 epoxy body.

Thermal performance is defined by two derating paths: 1.0 W at lead temperature < 105°C (3/8″ from body) or at ambient < 45°C on FR4 board with specified copper pads. Forward voltage is ≤1.2 V at 200 mA, confirming standard silicon PN junction behavior.

Key Specifications

Pinout & Package

DO-41 (DO-204AL) plastic axial-leaded package with cathode indicated by color band; terminals are anode and cathode only.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Zener regulation applications.

Compared with 1N4740A and BZX55C10, the 1N4740E3/TR13 offers full RoHS compliance, 1 W power capability, and superior thermal performance (45°C/W vs. ~120°C/W for DO-35), making it optimal for high-reliability industrial power rails where long-term stability and lead-free manufacturing are mandatory.

Availability

1N4740E3/TR13 is available at Aetrix Electronics and suitable for industrial power supplies, automotive body electronics, and test equipment requiring stable component supply, consistent Zener voltage tolerance, and RoHS-compliant packaging.

Supply support for 1N4740E3/TR13 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

Microsemi (now part of Microchip Technology) is a U.S.-based semiconductor company specializing in high-reliability analog and mixed-signal components for aerospace, defense, and industrial markets.

The 1N47xxA series was designed specifically for general-purpose voltage regulation in cost-sensitive, high-volume applications while maintaining JEDEC registration, military screening options, and robust thermal performance in plastic packages.

FAQ

What is the Zener voltage tolerance of the 1N4740E3/TR13?

The 1N4740E3/TR13 has a nominal Zener voltage of 10 V with a tolerance of ±5%, as confirmed by its "A" suffix per JEDEC standard. This tolerance applies at 25 mA test current and 25°C lead temperature. The "e3" suffix denotes RoHS-compliant matte-tin plating but does not affect voltage specification. Tighter tolerances (e.g., ±2% or ±1%) require "C" or "D" suffixes, which are not present in this part number.

Is the 1N4740E3/TR13 suitable for surface-mount assembly?

No, the 1N4740E3/TR13 uses a DO-41 axial-leaded package and is intended for through-hole mounting. While supplied on tape-and-reel (TR13), it is not a surface-mount device. Microsemi offers surface-mount equivalents such as SMAJ4740A and MLL4740A for SMT applications, but the 1N4740E3/TR13 itself requires hole-mounting with 3/8″ lead length considered in thermal design.

What is the maximum allowable surge current for the 1N4740E3/TR13?

The 1N4740E3/TR13 supports a maximum non-repetitive reverse surge current (I_SM) of 454 mA, measured using a ½-sine wave pulse of 1/120 second duration at 25°C ambient. This rating enables transient clamping in power line protection circuits. Exceeding this value risks irreversible junction damage, and repeated surges must allow full thermal recovery between events per derating curves in the Microsemi datasheet.

Does the 1N4740E3/TR13 require moisture preconditioning before reflow?

No, the 1N4740E3/TR13 is rated Moisture Sensitivity Level 1 per IPC/JEDEC J-STD-020B, meaning it may be stored indefinitely at ≤30°C/60% RH without dry packing or baking. This eliminates moisture-related popcorning risk during wave or hand soldering. The "e3" RoHS-compliant construction and void-free epoxy body further ensure robustness under standard solder profiles up to 260°C for 10 seconds.

How does thermal resistance differ between junction-to-lead and junction-to-ambient for the 1N4740E3/TR13?

The 1N4740E3/TR13 specifies 45°C/W junction-to-lead (at 3/8″ lead length) and 105°C/W junction-to-ambient on FR4 board (1 oz Cu, 4 mm² pad, 1 mm track). This 2.3× difference highlights that effective heat removal depends critically on lead termination: PCB traces alone provide poor conduction, so thermal design must prioritize short, wide leads and/or heatsinking at the lead exit point to sustain 1 W operation.