Microchip Technology 1N4733P/TR12

Overview

1N4733P/TR12 from Microsemi is a 5.1 V, 1 W axial-lead silicon Zener diode in DO-41 plastic package with ±5% voltage tolerance, 49 mA test current, and 7 Ω dynamic impedance at I_ZT. It provides stable voltage regulation in power supply reference, overvoltage protection, and biasing circuits across industrial temperature range.

For engineers reviewing the 1N4733P/TR12 datasheet, 1N4733P/TR12 pinout, 1N4733P/TR12 application, or 1N4733P/TR12 equivalent, key selection criteria include Zener voltage accuracy, thermal resistance (45 °C/W junction-to-lead), surge current rating (890 mA), reverse leakage (<10 µA @ 3.8 V), and RoHS-compliant matte-tin plating.

Technical Context

The 1N4733P/TR12 operates as a reverse-biased voltage reference device with sharp breakdown knee and low dynamic impedance. Its regulation performance is specified at 49 mA test current and validated across -65 °C to +150 °C operating temperature range.

Thermal design relies on junction-to-lead thermal resistance of 45 °C/W at 10 mm lead length, enabling 1.0 W dissipation at lead temperature <105 °C. Forward voltage is ≤1.2 V at 200 mA, confirming standard silicon PN junction behavior.

Key Specifications

Pinout & Package

DO-41 (DO-204AL) plastic molded package with axial leads; cathode indicated by band; polarity critical for Zener operation (banded end positive in reverse bias).

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N4733A and BZX55-C5V1, the 1N4733P/TR12 delivers full 1 W regulation capability in JEDEC-standard DO-41 with tape-and-reel support, making it optimal for production-grade power reference and clamp circuits requiring reliability, thermal margin, and automated assembly compatibility.

Availability

1N4733P/TR12 is available at Aetrix Electronics and suitable for power supply reference, overvoltage protection, and analog bias network applications requiring stable component supply, long-term lifecycle continuity, and RoHS-compliant sourcing.

Supply support for 1N4733P/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 and mixed-signal components for aerospace, defense, and industrial markets.

The 1N47xxAP series was designed specifically for robust, cost-effective voltage regulation in harsh-environment power systems where JEDEC-standard form factor, moisture resilience, and MIL-qualified screening options are essential.

FAQ

What is the Zener voltage tolerance of the 1N4733P/TR12?

The 1N4733P/TR12 has a nominal Zener voltage of 5.1 V with a tolerance of ±5%, as indicated by the "A" suffix in its JEDEC designation. This tolerance is guaranteed at 49 mA test current and 25 °C lead temperature. The "P" suffix confirms plastic DO-41 packaging, and "TR12" denotes EIA-296 tape-and-reel packaging with 12 mm carrier tape width. The 1N4733P/TR12 meets this specification under steady-state conditions per Microsemi's REV C datasheet.

Does the 1N4733P/TR12 require dry packing before PCB assembly?

No, the 1N4733P/TR12 is rated Moisture Sensitivity Level 1 per IPC/JEDEC J-STD-020B, meaning it does not require dry packing or baking prior to surface-mount assembly. Its void-free thermosetting epoxy body and matte-tin plating ensure moisture resistance and solderability without preconditioning. This simplifies manufacturing flow and reduces risk of popcorning during reflow. The 1N4733P/TR12 is fully qualified for standard lead-free reflow profiles up to 260 °C for 10 seconds.

What is the maximum surge current rating for the 1N4733P/TR12?

The 1N4733P/TR12 has a maximum non-repetitive surge current (I_SM) rating of 890 mA, measured using a ½ sine-wave pulse of 1/120 second duration at 25 °C ambient. This rating applies to transient overvoltage events such as ESD or inductive kickback. The 1N4733P/TR12 maintains regulation integrity under these conditions due to its low dynamic impedance (7 Ω) and robust junction construction, as verified in Microsemi's test methodology per Note 3 of the datasheet.

Can the 1N4733P/TR12 be used as a replacement for the glass-body 1N4733G?

The 1N4733P/TR12 is functionally equivalent to the 1N4733G in Zener voltage, tolerance, and electrical characteristics, but differs in package thermal performance: the plastic "P" version offers 45 °C/W junction-to-lead thermal resistance versus ~60 °C/W for the glass "G" variant. This makes the 1N4733P/TR12 better suited for higher-power dissipation in lead-conducted thermal paths. However, direct substitution requires mechanical verification of DO-41 footprint compatibility and thermal layout review, as the 1N4733P/TR12 is not a guaranteed drop-in replacement without validation.

What is the forward voltage specification for the 1N4733P/TR12?

The forward voltage of the 1N4733P/TR12 is specified as a maximum of 1.2 V at 200 mA forward current, consistent with standard silicon PN junction diode behavior. This parameter is relevant when the device is operated in forward conduction mode (e.g., as a protection diode or in dual-role circuits). The 1N4733P/TR12's forward characteristic is documented in the "Maximum Ratings" section of Microsemi's datasheet and supports design of bidirectional clamps or polarity-sensitive protection schemes.