Microchip Technology 1PMT5945/TR7

Overview

1PMT5945B from Microsemi is a 68 V, 3.0 W surface-mount Zener diode in the Powermite® package, featuring 5.5 mA test current, 120 Ω dynamic impedance at IZT, 1700 µA max reverse leakage at 51.2 V, and thermal resistance of 30°C/W junction-to-tab. It serves as a precision voltage reference or overvoltage clamp in DC power rails and regulator feedback paths.

For engineers reviewing the 1PMT5945B datasheet, 1PMT5945B pinout, 1PMT5945B application, or 1PMT5945B equivalent, key selection criteria include Zener voltage tolerance (±5%), ESD rating (>16 kV HBM), full metallic bottom for flux-free soldering, and compatibility with automated SMT insertion equipment.

Technical Context

This device operates as a single-terminal Zener diode with cathode designated by TAB 1. Its Powermite® package integrates a locking tab acting as an integral heat sink and provides direct thermal path from junction to tab with 30°C/W thermal resistance.

Rated for -55°C to +150°C junction/storage temperature, it delivers stable 68 V regulation at 5.5 mA test current with 120 Ω dynamic impedance and maintains ≤1700 µA reverse leakage at 51.2 V (75% of VZ), meeting industrial-grade reliability requirements.

Key Specifications

Pinout & Package

Package: Powermite® surface-mount molded package with full metallic bottom and integral heat-sink locking tab; cathode identified by TAB 1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMCJ68A and 1N5365B, the 1PMT5945B uniquely combines 3.0 W SMT power handling, integrated thermal tab, and ±5% Zener tolerance-enabling compact, self-contained regulation and clamping without layout compromises.

Availability

1PMT5945B is available at Aetrix Electronics and suitable for industrial power supplies, automotive body control modules, telecom line cards, and PLC analog input protection requiring stable component supply and long-lifecycle availability.

Supply support for 1PMT5945B 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.

The Powermite® Zener series was designed for high-power-density surface-mount voltage regulation and clamping in space-constrained, thermally demanding industrial and automotive systems.

FAQ

What is the Zener voltage tolerance for 1PMT5945B?

The 1PMT5945B has a standard Zener voltage tolerance of ±5% at 68 V, measured at 5.5 mA test current and TAB 1 temperature of 30°C. Tighter tolerances of ±2% (suffix C) and ±1% (suffix D) are available upon request. This tolerance directly impacts regulation accuracy in feedback loops and clamping thresholds in protection circuits.

How is thermal management handled in the 1PMT5945B package?

The 1PMT5945B uses the Powermite® package with an integral heat-sink locking tab (TAB 1) and full metallic bottom, achieving 30°C/W junction-to-tab thermal resistance. Effective thermal management requires direct connection of TAB 1 to a large PCB copper pour or internal ground plane. No additional heatsink is needed for continuous 3.0 W operation at TAB 1 ≤60°C.

Is the 1PMT5945B suitable for automated SMT assembly?

Yes, the 1PMT5945B is fully compatible with automated insertion equipment per EIA-481 tape-and-reel packaging (7″ reel: 3,000 pcs; 13″ reel: 12,000 pcs). Its Powermite® package geometry, flat bottom, and locking tab ensure stable pick-and-place accuracy and reliable reflow soldering without tombstoning or flux entrapment.

What is the maximum reverse leakage current for 1PMT5945B?

The 1PMT5945B specifies a maximum reverse leakage current (IR) of 1700 µA at 51.2 V (75% of nominal VZ), measured at TL = 30°C. This value ensures minimal standby power loss in high-impedance bias networks and preserves signal integrity in precision analog front-ends where leakage could introduce offset errors.

Does the 1PMT5945B have ESD protection built-in?

Yes, the 1PMT5945B features an ESD rating exceeding 16 kV per the Human Body Model (HBM), verified per ANSI/ESDA/JEDEC JS-001. This intrinsic robustness eliminates the need for discrete ESD protection components during board handling, testing, and field operation-reducing BOM count and improving system-level reliability.