Microchip Technology 1PMT5946/TR13

Overview

1PMT5946B from Microsemi is a 75 V, 3.0 W surface-mount Zener diode in the Powermite® package, featuring a full metallic bottom and integral heat sink locking tab. It delivers tight voltage regulation (±5% tolerance), low reverse leakage (≤2000 µA at 1 V), and ESD robustness (>16 kV HBM) for overvoltage protection in DC power rails and voltage reference circuits.

For engineers reviewing the 1PMT5946B datasheet, 1PMT5946B pinout, 1PMT5946B application, or 1PMT5946B equivalent, key selection criteria include its 75 V zener voltage at 5.0 mA test current, 140 Ω dynamic impedance, 56 mA maximum zener current, thermal resistance of 30°C/W (junction-to-tab), and DO-216 mechanical outline compatibility with automated SMT assembly.

Technical Context

This Zener diode operates as a precision voltage clamp and reference element in regulated power supplies and transient suppression circuits. Its Powermite® package integrates a metallic tab (TAB 1) as both cathode terminal and primary thermal path, enabling 3.0 W dissipation at 60°C tab temperature with verified 30°C/W junction-to-tab thermal resistance.

The device exhibits stable regulation across -55°C to +150°C junction temperature range, with knee current (IZK) of 0.25 mA and knee impedance (ZZK) of 2000 Ω - confirming sharp turn-on behavior suitable for low-current biasing and sensing applications where low-leakage operation below breakdown is critical.

Key Specifications

Pinout & Package

Package: Powermite® (DO-216), molded surface-mount package with full metallic bottom and integral heat sink locking tab. Cathode is designated by TAB 1; anode is the opposite end. 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 1PMT5946B uniquely combines SMT manufacturability, 3.0 W continuous dissipation via tab thermal coupling, and true Zener regulation - making it optimal for space-constrained, thermally demanding DC reference and clamping roles.

Availability

1PMT5946B is available at Aetrix Electronics and suitable for DC power rail protection, voltage reference circuits, industrial sensor excitation, and automotive control module clamp applications requiring stable component supply and consistent parametric performance across production batches.

Supply support for 1PMT5946B 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 series was designed for high-power-density surface-mount voltage regulation and transient clamping in harsh-environment systems where thermal management and assembly reliability are critical.

FAQ

What is the zener voltage tolerance for 1PMT5946B?

The standard 1PMT5946B has a zener voltage tolerance of ±5% at 75 V nominal. Tighter tolerances of ±2% (suffix C) and ±1% (suffix D) are available upon request. All variants are tested at 5.0 mA (IZT) with tab temperature held at 30°C, per Microsemi Note 202 methodology. The 1PMT5946B datasheet specifies this tolerance in Note 1 of the Electrical Characteristics table.

How is thermal management handled in the 1PMT5946B package?

The 1PMT5946B uses its metallic TAB 1 as the primary thermal conduction path, achieving 30°C/W junction-to-tab resistance. For full 3.0 W dissipation, TAB 1 must be soldered to ≥1 cm² of 2-oz copper on the PCB. The full metallic bottom prevents flux entrapment and ensures uniform thermal transfer. This design eliminates need for external heatsinks in most applications - a key advantage over conventional SOD-123 or DO-214AC packages.

Can 1PMT5946B be used in place of a through-hole Zener like 1N5365B?

The 1PMT5946B offers identical 75 V zener voltage and comparable electrical specs but differs critically in package and thermal behavior. Unlike the through-hole 1N5365B (TO-204AA), the 1PMT5946B uses surface-mount Powermite® packaging with integrated heat sink tab. Substitution requires PCB layout change and thermal validation - it is not a drop-in replacement. However, the 1PMT5946B enables higher density and automated assembly where space and process efficiency matter.

What is the maximum reverse leakage current for 1PMT5946B?

The 1PMT5946B has a maximum reverse leakage current (IR) of 2000 µA at 1 V reverse voltage, measured at TL = 30°C. This value remains stable across its -55°C to +150°C operating junction temperature range. Low IR ensures minimal quiescent power loss in always-on reference circuits - a critical parameter for battery-powered or energy-sensitive systems using the 1PMT5946B as a precision bias source.

Is 1PMT5946B compatible with standard SMT reflow profiles?

Yes, the 1PMT5946B is qualified for standard lead-free (SnAgCu) reflow profiles per J-STD-020, with peak temperature ≤260°C. Its molded Powermite® package and full metallic bottom ensure mechanical stability and flux-free solder joint formation. The device is supplied in EIA-481-compliant tape-and-reel format (3,000 pcs/7″ reel), fully compatible with high-speed pick-and-place equipment - confirming its suitability for automated manufacturing of the 1PMT5946B.