Microchip Technology 1PMT5940A/TR7

Overview

1PMT5940A/TR7 from Microsemi is a 43 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 53 Ω dynamic impedance at 8.7 mA test current and thermal resistance of 30°C/W junction-to-TAB1. It serves as a precision voltage reference or overvoltage clamp in power supply regulation and ESD-protected signal lines.

For engineers reviewing the 1PMT5940A/TR7 datasheet, 1PMT5940A/TR7 pinout, 1PMT5940A/TR7 application, or 1PMT5940A/TR7 equivalent, key selection criteria include Zener voltage accuracy, power derating capability above 60°C, low reverse leakage (<1 µA at 32.7 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 sharp Zener breakdown at 43 V nominal, specified under controlled thermal conditions (T_L = 30°C) and measured 20 seconds after DC current application to minimize self-heating effects. Its Powermite® package integrates a full metallic bottom and locking tab to ensure mechanical stability and efficient heat conduction away from the junction.

The 1PMT5940A/TR7 exhibits tight knee characteristics (I_ZK = 0.25 mA, Z_ZK = 950 Ω), enabling stable regulation even at low bias currents, and maintains <1 µA reverse leakage up to 32.7 V - supporting low-power standby and battery-backed circuits where leakage-induced drain must be minimized.

Key Specifications

Pinout & Package

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

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N5940B and BZX84-C43, the 1PMT5940A/TR7 delivers superior thermal management (30°C/W), automated assembly readiness, and intrinsic ESD hardness (>16 kV), making it uniquely suited for high-reliability, high-power SMT voltage regulation where junction temperature control and manufacturing scalability matter.

Availability

1PMT5940A/TR7 is available at Aetrix Electronics and suitable for industrial power supplies, automotive ECU protection circuits, and IoT sensor node voltage references requiring stable component supply and consistent tape-and-reel delivery.

Supply support for 1PMT5940A/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, mixed-signal, and radiation-hardened components for aerospace, defense, and industrial markets.

The Powermite® Zener series, including the 1PMT5940A/TR7, was engineered to deliver through-hole-level power handling in surface-mount form factors for mission-critical power regulation and transient suppression in harsh environments.

FAQ

What is the Zener voltage tolerance for the 1PMT5940A/TR7?

The 1PMT5940A/TR7 has a standard Zener voltage tolerance of ±5% at 43 V, measured at I_ZT = 8.7 mA with TAB 1 held at 30°C. Tighter tolerances (±2%, ±1%) are available with suffixes C and D respectively, but the /TR7 variant uses the standard ±5% grade. Voltage measurement must occur 20 seconds after DC current application to avoid self-heating errors.

How does the Powermite® package improve thermal performance of the 1PMT5940A/TR7?

The 1PMT5940A/TR7 achieves a junction-to-TAB1 thermal resistance of 30°C/W due to its full metallic bottom and integral locking tab - both acting as direct thermal conduction paths to the PCB. This is significantly lower than standard SMT Zeners (e.g., SOT-23: ~200°C/W), allowing the 1PMT5940A/TR7 to sustain 3.0 W dissipation at TAB 1 = 60°C without exceeding maximum junction temperature.

Is the 1PMT5940A/TR7 compatible with automated SMT assembly processes?

Yes, the 1PMT5940A/TR7 is specifically designed for automated insertion equipment. Its Powermite® package features a locking tab that enhances mechanical stability during pick-and-place, and it ships in EIA-481-compliant tape-and-reel format (3,000 pieces per 7-inch reel). The full metallic bottom also eliminates solder flux entrapment during reflow, reducing post-assembly defects.

What is the maximum reverse leakage current for the 1PMT5940A/TR7?

The 1PMT5940A/TR7 specifies a maximum reverse leakage current of 1 µA at V_R = 32.7 V (90% of nominal Zener voltage). This low leakage supports energy-sensitive applications such as battery-backed sensors and always-on monitoring circuits where standby current must remain below microampere thresholds.

Does the 1PMT5940A/TR7 meet any ESD immunity standards?

Yes, the 1PMT5940A/TR7 is rated for >16 kV per the Human Body Model (HBM) ESD test. This intrinsic immunity eliminates the need for additional discrete ESD protection components in many I/O and sensor interface applications, simplifying design and reducing bill-of-materials cost while maintaining robustness in electrostatic-prone environments.