Microchip Technology 1PMT5951/TR13

Overview

1PMT5951B from Microsemi is a 120 V, ±5% tolerance surface-mount Zener diode in the Powermite® package, rated for 3.0 W DC power dissipation at TAB 1 = 60°C, with 380 Ω dynamic impedance at 3.1 mA test current and 4500 µA max reverse leakage at 91.2 V, used for precision voltage regulation and overvoltage protection in power supply feedback loops.

For engineers reviewing the 1PMT5951B datasheet, 1PMT5951B pinout, 1PMT5951B application, or 1PMT5951B equivalent, key selection criteria include zener voltage accuracy, thermal resistance (30°C/W junction-to-TAB), ESD rating (>16 kV HBM), low knee impedance, and compatibility with automated SMT assembly.

Technical Context

This Zener diode operates in reverse breakdown mode to maintain stable reference voltage under varying load and temperature conditions. Its Powermite® package features a full metallic bottom and integral locking tab that serves as both mechanical anchor and heat sink, enabling efficient thermal conduction from junction to PCB via TAB 1.

The device exhibits tight regulation at its 120 V nominal zener voltage with 3.1 mA test current, 380 Ω dynamic impedance, and 4500 µA reverse leakage at 91.2 V. It supports operation across –55°C to +150°C junction temperature range and meets EIA-481 tape-and-reel packaging standards.

Key Specifications

Pinout & Package

Package: Powermite® surface-mount molded package with full metallic bottom and integral locking tab; cathode designated by TAB 1; weight ≈ 0.016 g; DO-216 outline.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMCJ120A and BZX84-C120, the 1PMT5951B uniquely combines 3.0 W continuous power handling, 30°C/W thermal resistance, and DO-216-compatible footprint-enabling high-stability regulation in thermally demanding power stages where TVS devices lack precision and SOT-23 Zeners lack power capability.

Availability

1PMT5951B is available at Aetrix Electronics and suitable for switch-mode power supplies, industrial overvoltage protection circuits, and high-voltage sensor excitation systems requiring stable component supply and consistent parametric performance across production lots.

Supply support for 1PMT5951B 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 semiconductor manufacturer specializing in high-reliability analog, mixed-signal, and radiation-hardened components for aerospace, defense, and industrial markets.

The Powermite® Zener series was designed for high-power-density voltage regulation in space-constrained, thermally aggressive environments such as telecom power modules and motor drive control boards.

FAQ

What is the zener voltage tolerance for the 1PMT5951B?

The standard 1PMT5951B has a zener voltage tolerance of ±5% at 120 V nominal. Tighter tolerances are available: ±2% with suffix C (1PMT5951C) and ±1% with suffix D (1PMT5951D). All variants maintain identical thermal and packaging specifications. The 1PMT5951B datasheet specifies measurement at 3.1 mA test current with TAB 1 held at 30°C.

How is thermal management handled for the 1PMT5951B in high-power applications?

The 1PMT5951B uses TAB 1 as its primary thermal path, with a specified junction-to-TAB thermal resistance of 30°C/W. Effective thermal management requires soldering TAB 1 to a minimum 100 mm² copper pour on the PCB. The 1PMT5951B achieves 3.0 W dissipation only when TAB 1 temperature is maintained at ≤60°C; derating is required above this temperature.

Can the 1PMT5951B replace through-hole zener diodes in existing designs?

The 1PMT5951B is not a direct drop-in replacement for through-hole zeners due to its DO-216 surface-mount footprint and thermal reliance on TAB 1 conduction. However, it can replace axial-lead 1N5388B (120 V, 5 W) in space-constrained layouts if PCB layout accommodates the Powermite® pad dimensions and thermal pad design. The 1PMT5951B offers superior ESD immunity (>16 kV HBM) versus legacy through-hole parts.

What is the maximum reverse leakage current specification for the 1PMT5951B?

The 1PMT5951B has a maximum reverse leakage current of 4500 µA at a reverse voltage of 91.2 V, measured at TL = 30°C. This value reflects worst-case leakage under specified test conditions and is critical for high-impedance bias networks. Leakage increases with temperature and voltage; the 1PMT5951B datasheet provides derating curves for elevated operating conditions.

Is the 1PMT5951B compatible with lead-free reflow profiles?

Yes, the 1PMT5951B is qualified for lead-free reflow processing per JEDEC J-STD-020. Its Powermite® package withstands peak temperatures up to 260°C for 30 seconds. The full metallic bottom ensures uniform thermal distribution during reflow, reducing warpage risk. The 1PMT5951B's moisture sensitivity level is MSL 1, eliminating bake requirements prior to assembly.