Microchip Technology 1PMT5955/TR13

Overview

1PMT5955B from Microsemi is a 180 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 900 Ω dynamic impedance at 2.1 mA test current and 7000 µA max reverse leakage at 136.8 V. It serves as a precision voltage reference or overvoltage clamp in high-reliability power supply feedback loops.

For engineers reviewing the 1PMT5955B datasheet, 1PMT5955B pinout, 1PMT5955B application, or 1PMT5955B equivalent, key selection criteria include its 180 V nominal Zener voltage, 3.0 W thermal capability via metallic tab, DO-216 mechanical outline, ESD rating >16 kV HBM, and compatibility with automated SMT assembly.

Technical Context

This Zener diode operates in reverse breakdown mode to maintain stable voltage regulation under varying load and temperature conditions. Its Powermite® package features a full metallic bottom (TAB 1) acting as both cathode terminal and primary heat path, with thermal resistance of 30°C/W junction-to-tab.

The device exhibits low knee impedance (ZZK = 0.25 Ω) and tight voltage tolerance options (±1%, ±2% with suffixes D/C), supporting precision clamping in industrial power converters and telecom surge protection circuits where stable reference voltage and robust ESD immunity (>16 kV HBM) are required.

Key Specifications

Pinout & Package

Package: Powermite® (DO-216AA), molded surface-mount case with full metallic bottom (TAB 1) serving as cathode and thermal interface. Dimensions conform to Microsemi mechanical drawing MSC0995, all tolerances ±0.005 inch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMCJ180A and 1N5388B, the 1PMT5955B uniquely combines surface-mount compatibility, integrated thermal tab (30°C/W), and precision Zener regulation in a single DO-216 package-making it optimal for space-constrained, thermally demanding, and accuracy-critical applications.

Availability

1PMT5955B is available at Aetrix Electronics and suitable for industrial power supplies, telecom surge protection circuits, test equipment references, and avionics monitoring systems requiring stable component supply and long-term lifecycle continuity.

Supply support for 1PMT5955B 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 RF solutions for aerospace, defense, and industrial markets.

The Powermite® Zener diode product line was engineered for high-power-density, surface-mount voltage regulation and clamping in mission-critical power systems where thermal performance and assembly reliability are paramount.

FAQ

What is the Zener voltage tolerance for 1PMT5955B?

The standard 1PMT5955B has a Zener voltage tolerance of ±5% at 180 V nominal. Tighter tolerances are available: ±2% with suffix C (1PMT5955BC) and ±1% with suffix D (1PMT5955BD). All variants retain identical thermal and electrical characteristics except for voltage specification. The 1PMT5955B datasheet specifies measurement at I_ZT = 2.1 mA and T_C = 30°C.

How is thermal management handled in the 1PMT5955B package?

The 1PMT5955B uses the Powermite® package with a full metallic bottom (TAB 1) that serves as both cathode and primary thermal interface. Its specified thermal resistance is 30°C/W junction-to-TAB1, meaning a 3.0 W dissipation causes ~90°C rise above tab temperature. Effective PCB copper pour under TAB 1 is essential. The 1PMT5955B does not require external heatsinks when properly mounted.

Is 1PMT5955B compatible with lead-free reflow processes?

Yes, the 1PMT5955B is qualified for lead-free reflow soldering per J-STD-020. Its Powermite® package withstands peak temperatures up to 260°C for 10 seconds. The full metallic bottom ensures uniform thermal expansion and minimizes warpage risk. The 1PMT5955B's tape-and-reel packaging (EIA-481) supports automated placement prior to reflow.

What is the maximum reverse leakage current for 1PMT5955B?

The 1PMT5955B has a maximum reverse leakage current (I_R) of 7000 µA at V_R = 136.8 V, measured at T_L = 30°C. This value defines the upper bound of off-state conduction before reaching the Zener knee. At lower reverse voltages (e.g., 100 V), leakage drops significantly. The 1PMT5955B's low leakage supports stable operation in high-impedance reference circuits.

Does 1PMT5955B have a defined polarity marking?

Yes, the 1PMT5955B cathode is designated by TAB 1, which is the full metallic bottom surface. The anode is the smaller lead (Lead 2). No additional marking is present on the molded body; orientation must be verified by physical tab location per DO-216 mechanical drawing MSC0995. Correct polarity is critical-reverse mounting prevents proper Zener operation and may cause thermal runaway in the 1PMT5955B.