Microchip Technology 1PMT5947/TR7

Overview

1PMT5947B from Microsemi is a 3.0 W surface-mount Zener diode in the Powermite® package, providing 82 V nominal Zener voltage at 4.6 mA test current, 160 Ω dynamic impedance, and 2500 µA maximum reverse leakage at 62.2 V. It serves as a precision voltage reference or overvoltage clamp in power supply regulation and transient protection circuits.

For engineers reviewing the 1PMT5947B datasheet, 1PMT5947B pinout, 1PMT5947B application, or 1PMT5947B equivalent, key selection factors include its 82 V Zener voltage tolerance (±5%), 30°C/W junction-to-tab thermal resistance, ESD rating >16 kV HBM, and compatibility with automated SMT assembly using EIA-481 tape-and-reel packaging.

Technical Context

This Zener diode operates in reverse breakdown mode to maintain stable voltage across load variations and temperature shifts. Its Powermite® package features a full metallic bottom for flux-free soldering and an integral locking tab acting as both mechanical anchor and heat sink-enabling efficient thermal transfer to PCB copper.

The device exhibits low knee impedance (0.25 Ω) and tight voltage regulation under 4.6 mA test current, with reverse leakage capped at 2500 µA at 62.2 V. Junction temperature range spans –55°C to +150°C, supporting industrial and automotive under-hood applications requiring robust thermal performance.

Key Specifications

Pinout & Package

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

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N5365B and BZX84-C82, the 1PMT5947B uniquely combines SMT compatibility, 3.0 W power handling, and integrated thermal management via its metallic tab-making it the only option capable of replacing through-hole Zeners in automated, thermally demanding industrial power designs.

Availability

1PMT5947B is available at Aetrix Electronics and suitable for switch-mode power supplies, automotive load-dump protection, industrial sensor conditioning, and programmable logic controller input protection requiring stable component supply and long-lifecycle availability.

Supply support for 1PMT5947B 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 family-including 1PMT5947B-is engineered for high-power surface-mount voltage regulation and transient suppression in harsh-environment power systems where thermal performance and assembly reliability are critical.

FAQ

What is the Zener voltage tolerance for 1PMT5947B?

The 1PMT5947B has a standard Zener voltage tolerance of ±5% at 82 V nominal. Tighter tolerances of ±2% (suffix C) and ±1% (suffix D) are available upon request. Voltage is measured at 4.6 mA test current with TAB1 held at 30°C, and readings must be taken within 20 seconds of applying DC current to avoid self-heating effects. This tolerance directly impacts regulation accuracy in feedback and reference applications.

How is thermal management implemented for 1PMT5947B?

Thermal management for 1PMT5947B relies on its metallic TAB 1, which serves as both cathode and primary heat conduction path. With a junction-to-tab thermal resistance of 30°C/W, effective cooling requires soldering TAB 1 to ≥1 in² of 2-oz copper on the PCB. The full metallic bottom prevents flux entrapment, ensuring consistent thermal interface quality after reflow. No external heatsink is needed if PCB copper area meets minimum size requirements.

Is 1PMT5947B compatible with lead-free reflow processes?

Yes, 1PMT5947B is qualified for lead-free reflow soldering per JEDEC J-STD-020. Its Powermite® package withstands peak temperatures up to 260°C for 10 seconds. The full metallic bottom and molded construction ensure mechanical integrity and void-free solder joints. Process validation data confirms no degradation in Zener voltage or leakage performance after exposure to standard Pb-free thermal profiles.

What is the maximum reverse voltage that can be applied to 1PMT5947B without breakdown?

The maximum non-breakdown reverse voltage for 1PMT5947B is 62.2 V, specified as the reverse voltage (V_R) at which reverse leakage current reaches 2500 µA. Operation below this voltage ensures the device remains in high-impedance blocking mode. Exceeding 62.2 V initiates controlled Zener conduction-intended behavior only when power dissipation remains within the 3.0 W limit and thermal design accommodates junction temperature rise.

Does 1PMT5947B require derating at elevated ambient temperatures?

Yes, 1PMT5947B requires linear power derating above 60°C tab temperature. At TAB1 = 100°C, maximum allowable power drops to 2.0 W; at 150°C, it falls to zero. Derating follows the formula P_D(T) = 3.0 W × (1 − (T_TAB − 60)/90). This reflects its 30°C/W thermal resistance and ensures junction temperature stays within the –55°C to +150°C rating. PCB layout must provide adequate copper area to maintain TAB1 temperature.