Microchip Technology 1N4743P/TR8

Overview

1N4743P/TR8 from Microsemi is a 13 V, 1 W plastic-encapsulated Zener diode with ±5% voltage tolerance, 19 mA test current, and 10 Ω dynamic impedance at I_ZT, used for precision voltage regulation in power supply reference and overvoltage protection circuits.

For engineers reviewing the 1N4743P/TR8 datasheet, 1N4743P/TR8 pinout, 1N4743P/TR8 application, or 1N4743P/TR8 equivalent, key selection factors include its DO-41 package thermal resistance (45 °C/W junction-to-lead), 0.25 A maximum regulator current at 50 °C, and RoHS-compliant "e3" plating option.

Technical Context

This discrete Zener diode operates in reverse breakdown to maintain stable output voltage across varying load and line conditions. It delivers regulation with 10 Ω dynamic impedance at 19 mA test current and exhibits a temperature coefficient of +3.5 mV/°C near 13 V, supporting predictable drift compensation in analog references.

Designed for axial-lead mounting on FR4 PCBs, it sustains 1.0 W dissipation at lead temperature <105 °C (3/8″ from body) or ambient <45 °C, with thermal resistance of 105 °C/W junction-to-ambient under standard 4 mm² copper pad conditions.

Key Specifications

Pinout & Package

Package: DO-41 (DO-204AL) plastic molded case, axial-leaded, cathode indicated by band; RoHS-compliant matte-tin plating; weight 0.7 g.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N4743A and MMBZ5242BS, the 1N4743P/TR8 offers full 1 W dissipation in a tape-and-reel–ready axial package, enabling high-reliability through-hole production without requalification of thermal or mechanical interfaces.

Availability

1N4743P/TR8 is available at Aetrix Electronics and suitable for power supply reference, overvoltage protection, and analog sensor biasing applications requiring stable component supply and JEDEC-standard compliance.

Supply support for 1N4743P/TR8 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, RF, and timing solutions for aerospace, defense, and industrial markets.

The 1N47xxAP series was engineered for robust voltage regulation in harsh-environment power systems, emphasizing long-term stability, MIL-grade screening options, and moisture-insensitive packaging.

FAQ

What is the Zener voltage tolerance of the 1N4743P/TR8?

The 1N4743P/TR8 has a nominal Zener voltage of 13 V with a tolerance of ±5%, as indicated by the "A" suffix in its JEDEC designation. This tolerance is guaranteed at 19 mA test current and 25 °C lead temperature, and applies across the full operating temperature range of –65 °C to +150 °C per Microsemi's published specifications.

Does the 1N4743P/TR8 support automated assembly?

Yes, the 1N4743P/TR8 is supplied in EIA-296 standard tape-and-reel format (TR8 designation), enabling direct integration into pick-and-place equipment. Its DO-41 axial package is compatible with industry-standard feeders and vision alignment systems, and its RoHS-compliant matte-tin plating ensures reliable solder wetting without post-assembly cleaning.

What is the maximum continuous current for the 1N4743P/TR8 at 70 °C ambient?

At 70 °C ambient temperature on an FR4 PCB with 1 oz copper, the 1N4743P/TR8 must be derated per its power curve. With a thermal resistance of 105 °C/W junction-to-ambient, its usable power drops to ~0.76 W, limiting maximum continuous Zener current to approximately 260 mA - well below its 344 mA I_ZM rating at 50 °C.

How does the 1N4743P/TR8 differ from the glass-body 1N4743G variant?

The 1N4743P/TR8 uses a void-free thermosetting epoxy DO-41 package, delivering 45 °C/W junction-to-lead thermal resistance versus ~60 °C/W for the glass-bodied 1N4743G. This lower thermal resistance allows higher sustained power in leaded applications and eliminates moisture sensitivity concerns inherent in glass encapsulation.

Is the 1N4743P/TR8 suitable for automotive applications?

The 1N4743P/TR8 meets AEC-Q200 stress test requirements when screened to JAN or JANTX levels (e.g., MQ1N4743P/TR8). In standard commercial form, it operates reliably from –65 °C to +150 °C and withstands solder reflow up to 260 °C for 10 s, making it viable for under-hood modules where full qualification is not mandated.