Microchip Technology 1PMT5943/TR13

Overview

1PMT5943B from Microsemi is a 56 V, ±5% tolerance surface-mount Zener diode in the Powermite® package, rated for 3.0 W DC power dissipation at TAB 1 temperature of 60°C, with 86 Ω dynamic impedance at 6.7 mA test current, and designed for precision voltage regulation in space-constrained power supply rails.

For engineers reviewing the 1PMT5943B datasheet, 1PMT5943B pinout, 1PMT5943B application, or 1PMT5943B equivalent, key selection considerations include its 56 V nominal Zener voltage, 3.0 W thermal capability with metallic-tab heat sinking, low reverse leakage (≤1 µA at 42.6 V), and ESD rating >16 kV HBM - critical for robust overvoltage protection in industrial DC-DC converters and automotive body control modules.

Technical Context

This Zener diode operates as a two-terminal voltage reference and clamp device, with cathode designated by TAB 1 and full metallic bottom enabling direct thermal conduction to PCB copper. Its 30°C/W junction-to-TAB thermal resistance supports stable regulation under sustained 3.0 W dissipation when mounted on adequate copper area.

The device exhibits tight knee characteristics (IZK = 0.25 mA, ZZK = 1300 Ω), enabling reliable low-current regulation down to microampere-level biasing, and maintains ≤1 µA reverse leakage up to 42.6 V - making it suitable for low-power sensing and reference buffering where leakage-induced error must be minimized.

Key Specifications

Pinout & Package

Package: Powermite® surface-mount molded package with full metallic bottom and integral locking tab acting as thermal path and mechanical anchor. Cathode is designated by TAB 1; anode is the opposite terminal. Mounting orientation is unrestricted.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMCJ56A and BZX84-C56, the 1PMT5943B uniquely combines 3.0 W continuous Zener regulation, low-leakage clamping, and integrated thermal management - making it the only option among the three capable of stable 56 V reference generation under sustained load in compact industrial power supplies.

Availability

1PMT5943B is available at Aetrix Electronics and suitable for industrial power supply regulation, automotive body control module clamping, test equipment reference buffering, and telecom DC-DC converter feedback requiring stable component supply with consistent parametric performance across production lots.

Supply support for 1PMT5943B 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, mixed-signal, and radiation-hardened components for aerospace, defense, and industrial markets.

The Powermite® Zener diode product line was engineered to deliver high-power surface-mount voltage regulation in minimal footprint - addressing thermal and reliability constraints in mission-critical power systems where leaded packages were previously required.

FAQ

What is the maximum continuous power dissipation rating for the 1PMT5943B?

The 1PMT5943B is rated for 3.0 W DC power dissipation when TAB 1 temperature is maintained at 60°C. This rating assumes proper thermal management via soldering TAB 1 to sufficient PCB copper area, leveraging its 30°C/W junction-to-TAB thermal resistance. Derating is required above 60°C TAB temperature per the device's thermal curve.

How is cathode identification implemented on the 1PMT5943B package?

The cathode of the 1PMT5943B is unambiguously designated by TAB 1 - the larger metallic terminal on the package bottom. This is confirmed in the mechanical specifications section of the MSC0995.PDF datasheet and is consistent across all 1PMT59xxB series devices. The opposite terminal serves as the anode.

Does the 1PMT5943B meet any industry-standard ESD ratings?

Yes, the 1PMT5943B has an ESD rating exceeding 16 kV per the Human Body Model (HBM), as specified in the FEATURES section of the MSC0995.PDF datasheet. This level of robustness eliminates the need for additional ESD protection in many board-level implementations, particularly in industrial control and automotive subsystems.

What is the reverse leakage current specification for the 1PMT5943B at its rated clamping voltage?

At a reverse voltage of 42.6 V - which corresponds to 76% of its 56 V nominal Zener voltage - the 1PMT5943B exhibits a maximum reverse leakage current of 1 µA. This value is explicitly listed in the Electrical Characteristics table under "REVERSE CURRENT IR (MAX)" for part number 1PMT5943B.

Can the 1PMT5943B be used in automated SMT assembly lines?

Yes, the 1PMT5943B is fully compatible with automated insertion equipment. Its Powermite® package features a unique locking tab and full metallic bottom that prevent flux entrapment and ensure mechanical stability during reflow. It is supplied in EIA-481 standard tape-and-reel format (3,000 pieces per 7-inch reel), supporting high-throughput SMT placement.