Microchip Technology 1PMT5955/TR7

Overview

1PMT5955B from Microsemi is a 180 V, ±5% tolerance Zener diode in Powermite® surface-mount 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 thermal resistance of 30°C/W junction-to-TAB1. It serves as precision voltage reference or overvoltage clamp in high-reliability power supply regulation circuits.

For engineers reviewing the 1PMT5955B datasheet, 1PMT5955B pinout, 1PMT5955B application, or 1PMT5955B equivalent, key selection criteria include zener voltage stability under thermal stress, low reverse leakage (<1 µA at 136.8 V), ESD robustness (>16 kV HBM), and compatibility with automated SMT assembly using EIA-481 tape-and-reel packaging.

Technical Context

This device operates as a two-terminal voltage-regulating diode with cathode designated by TAB 1. Its Powermite® package integrates a full metallic bottom to prevent solder flux entrapment and a locking tab that functions as an integral heat sink, enabling direct thermal conduction from junction to PCB copper.

Zener voltage is specified at 180 V ±5% (standard tolerance) with test current I_ZT = 2.1 mA and measurement performed 20 seconds after DC current application. Dynamic impedance (Z_ZT) is measured using 60 Hz RMS AC current equal to 10% of I_ZT, yielding 900 Ω - indicating moderate regulation sensitivity near knee region.

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; mounting position unrestricted; weight ≈ 0.016 g.

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 SMT compatibility, 3.0 W DC regulation capability, and 30°C/W thermal resistance in a compact Powermite® package - making it optimal for space-constrained, thermally demanding Zener reference or clamping applications where precision and manufacturability are co-priorities.

Availability

1PMT5955B is available at Aetrix Electronics and suitable for industrial power supply regulation, automotive battery monitoring, test equipment reference circuits, and high-voltage LED driver protection requiring stable component supply and traceable sourcing.

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 and mixed-signal components for aerospace, defense, and industrial markets.

The Powermite® Zener diode product line was engineered for high-power density surface-mount voltage regulation in thermally constrained environments, emphasizing manufacturability, ESD resilience, and stable DC performance across extended temperature ranges.

FAQ

What is the Zener voltage tolerance for 1PMT5955B?

The standard 1PMT5955B has a Zener voltage tolerance of ±5% at 180 V, measured at I_ZT = 2.1 mA with TAB 1 held at 30°C. Tighter tolerances (±2% and ±1%) are available with suffixes C and D respectively, but those are distinct orderable variants - the base 1PMT5955B is ±5%.

How is thermal management handled in the 1PMT5955B package?

The 1PMT5955B uses Microsemi's Powermite® package with an integral heat-sink locking tab and full metallic bottom. Thermal resistance is specified as 30°C/W junction-to-TAB1, meaning effective cooling requires soldering TAB 1 directly to a copper pour on the PCB to dissipate its 3.0 W maximum power rating reliably.

Can 1PMT5955B be used in place of a through-hole Zener like 1N5388B?

The 1PMT5955B provides equivalent 180 V Zener functionality but in a surface-mount Powermite® package. While electrically comparable, it is not a drop-in replacement due to different footprint and thermal interface requirements. PCB layout and reflow profile must be adapted to accommodate its TAB 1 cathode and metallic bottom thermal path.

What is the maximum reverse leakage current for 1PMT5955B?

Per the datasheet, the maximum reverse leakage current (I_R) for 1PMT5955B is 1 µA at V_R = 136.8 V and T_L = 30°C. This low leakage supports use in high-impedance bias networks and precision reference circuits where standby current must be minimized.

Is 1PMT5955B compatible with automated SMT assembly processes?

Yes, the 1PMT5955B is supplied in EIA-481 compliant tape-and-reel format (3,000 pieces per 7-inch reel) and designed for compatibility with automatic insertion equipment. Its Powermite® package features a locking tab and flux-free metallic bottom, reducing defects and eliminating post-assembly cleaning requirements.