Microchip Technology 1N4734AP/TR12

Overview

1N4734AP/TR12 from Microsemi is a 5.6 V, ±5% tolerance, 1 W axial-lead silicon Zener diode in DO-41 plastic package, rated for 45 mA test current (IZT), 5 Ω dynamic impedance (ZZT), and 162 mA maximum regulator current (IZM) at 50°C. It provides stable voltage regulation in power supply reference and overvoltage protection circuits.

For engineers reviewing the 1N4734AP/TR12 datasheet, 1N4734AP/TR12 pinout, 1N4734AP/TR12 application, or 1N4734AP/TR12 equivalent, key selection criteria include Zener voltage tolerance, thermal resistance (45 °C/W junction-to-lead), surge current rating (810 mA), reverse leakage (10 μA @ 4.2 V), and RoHS-compliant "e3" plating compatibility with automated assembly.

Technical Context

The 1N4734AP/TR12 operates as a two-terminal voltage reference device, conducting in reverse breakdown to maintain a stable 5.6 V across its terminals within ±5% tolerance over temperature and current variations. Its Zener knee is characterized by 0.5 mA test current (IZK) and 400 Ω maximum knee impedance (ZZK), ensuring predictable turn-on behavior in low-current biasing applications.

Designed for through-hole mounting on FR4 PCBs with 1 oz copper, it delivers 1.0 W steady-state power 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 defined pad layout (4 mm² copper, 1 mm track width).

Key Specifications

Pinout & Package

DO-41 (DO-204AL) plastic axial-lead package with cathode indicated by colored band; leads are tin-lead or RoHS-compliant matte-tin plated per MIL-STD-750 Method 2026.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N4734A and MMBZ5232BS, the 1N4734AP/TR12 uniquely combines 1 W power handling, DO-41 mechanical robustness, and EIA-296 tape-and-reel delivery-making it optimal for industrial power supply designs requiring field-replaceable through-hole components with automated assembly support.

Availability

1N4734AP/TR12 is available at Aetrix Electronics and suitable for power supply reference, overvoltage protection, and current source biasing applications requiring stable component supply, long-term obsolescence management, and RoHS-compliant manufacturing.

Supply support for 1N4734AP/TR12 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 developed to deliver JEDEC-standardized, high-stability Zener regulation in ruggedized plastic packages for mission-critical power conditioning and protection functions.

FAQ

What is the Zener voltage tolerance of the 1N4734AP/TR12?

The 1N4734AP/TR12 has a Zener voltage tolerance of ±5%, as indicated by the "A" suffix in its part number per JEDEC registration. This means its nominal 5.6 V breakdown voltage is guaranteed between 5.32 V and 5.88 V when tested at 45 mA (IZT) and 25°C lead temperature. The tolerance remains valid across its full operating temperature range of –65°C to +150°C, supporting reliable performance in harsh environments where the 1N4734AP/TR12 is deployed.

Does the 1N4734AP/TR12 support lead-free soldering processes?

Yes, the 1N4734AP/TR12 is offered in RoHS-compliant form with "e3" suffix plating (annealed matte-tin), qualified for lead-free reflow soldering at 260°C for up to 10 seconds. Its DO-41 package body meets UL94V-0 flammability rating, and the terminal plating complies with MIL-STD-750 Method 2026 for solderability. This makes the 1N4734AP/TR12 suitable for modern electronics assembly lines requiring full RoHS compliance without derating or process modification.

What is the maximum continuous current the 1N4734AP/TR12 can regulate at room temperature?

The 1N4734AP/TR12 supports a maximum continuous regulator current (IZM) of 162 mA at 50°C ambient, derived from its 1.0 W power rating and thermal characteristics. At 25°C ambient with proper lead heatsinking (3/8" from body), it safely handles up to approximately 178 mA before exceeding junction temperature limits. Engineers must apply derating curves from the datasheet when operating above 45°C ambient or on non-ideal PCB layouts, as the 1N4734AP/TR12's thermal resistance rises significantly in still air.

How does the 1N4734AP/TR12 differ from the glass-body 1N4734A version?

The 1N4734AP/TR12 uses a void-free thermosetting epoxy plastic body (DO-41), whereas the 1N4734A uses a glass envelope (DO-204AH). The plastic version offers lower thermal resistance (45 °C/W vs. ~60 °C/W), improved moisture resistance (MSL Level 1, no dry pack required), and enhanced mechanical ruggedness. Both share identical electrical specs, but the 1N4734AP/TR12 is preferred for high-volume industrial applications where reliability under thermal cycling and humidity exposure is critical.

Can the 1N4734AP/TR12 be used in place of a 5.1 V Zener like the 1N4733A?

No-the 1N4734AP/TR12 is specifically rated for 5.6 V Zener voltage and is not interchangeable with the 5.1 V 1N4733A without circuit redesign. Their test currents differ (45 mA vs. 49 mA), dynamic impedances differ (5 Ω vs. 7 Ω), and regulation points shift by 0.5 V, which may cause overvoltage stress or insufficient bias in feedback loops calibrated for 5.1 V. Always verify reference voltage requirements before substituting any Zener, including the 1N4734AP/TR12.