Microchip Technology 1PMT5946E3/TR7

Overview

1PMT5946E3/TR7 from Microsemi is a 75 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 dynamic impedance of 140 Ω at 5.0 mA test current, and reverse leakage ≤2000 µA at 60 V, used for precision voltage regulation in space-constrained industrial power supplies.

For engineers reviewing the 1PMT5946E3/TR7 datasheet, 1PMT5946E3/TR7 pinout, 1PMT5946E3/TR7 application, or 1PMT5946E3/TR7 equivalent, key selection criteria include Zener voltage tolerance, thermal resistance (30°C/W junction-to-TAB), ESD rating (>16 kV HBM), low knee impedance, and compatibility with automated SMT assembly per EIA-481 tape-and-reel packaging.

Technical Context

This Zener diode operates as a two-terminal voltage reference device with cathode designated by TAB 1, featuring a full metallic bottom to prevent solder flux entrapment and integral locking tabs acting as heat sinks. Its DO-216 mechanical outline supports high-reliability mounting in any orientation.

Designed for stable regulation under varying load and temperature, it delivers 75 V nominal Zener voltage at 5.0 mA test current (IZT), with 140 Ω dynamic impedance (ZZT) and 2500 Ω knee impedance (ZZK) at 0.25 mA (IZK), enabling sharp breakdown characteristics suitable for feedback and protection circuits.

Key Specifications

Pinout & Package

The 1PMT5946E3/TR7 uses the DO-216 surface-mount package (Powermite®), with a molded body, full metallic bottom, and cathode identified by TAB 1. Mounting orientation is unrestricted.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMCJ75A and 1N5365B, the 1PMT5946E3/TR7 uniquely combines surface-mount manufacturability, integrated thermal management via TAB 1, and true Zener regulation capability - making it optimal for high-density, high-reliability SMT power conditioning where both precision and assembly robustness matter.

Availability

1PMT5946E3/TR7 is available at Aetrix Electronics and suitable for industrial power supply regulation, overvoltage protection circuits, and programmable logic controller input conditioning requiring stable component supply across extended temperature ranges and high-volume production cycles.

Supply support for 1PMT5946E3/TR7 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 Powermite® Zener diode product line was engineered for ruggedized surface-mount voltage regulation in space-constrained, thermally demanding environments - emphasizing manufacturability, thermal performance, and ESD resilience.

FAQ

What is the Zener voltage tolerance for 1PMT5946E3/TR7?

The 1PMT5946E3/TR7 has a standard Zener voltage tolerance of ±5% at 75 V nominal, measured at 5.0 mA test current with TAB 1 held at 30°C. Tighter tolerances (±2%, ±1%) are available with suffixes C and D, but the E3/TR7 variant specifies ±5%. This tolerance directly impacts regulation accuracy in feedback loops and reference networks using the 1PMT5946E3/TR7.

Does 1PMT5946E3/TR7 support automated SMT assembly?

Yes, the 1PMT5946E3/TR7 is supplied in EIA-481 compliant tape-and-reel format (3,000 units per 7-inch reel), designed explicitly for compatibility with high-speed pick-and-place equipment. Its Powermite® package features integral locking tabs and a full metallic bottom that prevent flux entrapment - critical for consistent reflow yield. The 1PMT5946E3/TR7 meets industry standards for automated SMT line integration without process modification.

What is the thermal resistance of 1PMT5946E3/TR7, and how does it affect PCB layout?

The 1PMT5946E3/TR7 has a junction-to-TAB1 thermal resistance of 30°C/W. Since TAB 1 is the cathode and primary thermal path, PCB layout must maximize copper area connected to TAB 1 to dissipate 3.0 W reliably. Without adequate copper pour or thermal vias, junction temperature rise exceeds ratings. This thermal specification directly governs minimum pad size and thermal via count in designs using the 1PMT5946E3/TR7.

Can 1PMT5946E3/TR7 be used for overvoltage clamping in 48 V systems?

Yes, the 1PMT5946E3/TR7 is routinely applied for clamping transients on 48 V rails, where its 75 V Zener voltage provides sufficient margin above normal operating voltage while limiting fault voltage to a safe level. With 3.0 W continuous dissipation and >16 kV HBM ESD rating, the 1PMT5946E3/TR7 sustains repetitive surges without degradation - provided TAB 1 is thermally coupled to PCB ground plane per its 30°C/W spec.

How does the Powermite® package differ from standard SOD-123 or DO-214AC packages?

The Powermite® package of the 1PMT5946E3/TR7 features a full metallic bottom and integral locking tabs - unlike SOD-123 or DO-214AC - enabling superior heat transfer to the PCB and eliminating solder flux entrapment. Its DO-216 outline also provides higher power density (3.0 W vs. typical 1.0–1.5 W) in comparable footprint. These structural differences make the 1PMT5946E3/TR7 uniquely suited for high-reliability, high-power SMT Zener applications where thermal and assembly integrity are critical.