Microchip Technology 1N5344E3/TR8

Overview

1N5344E3/TR8 from Microsemi is a 5 W axial-leaded silicon Zener diode with nominal regulation voltage of 8.2 V, ±5% tolerance (B-suffix equivalent), 150 mA maximum Zener current (IZM), 150 Ω dynamic impedance (ZZ) at 150 mA test current, and operates from –65°C to +150°C. It serves as a precision voltage reference in power supply feedback loops, overvoltage clamping circuits, and analog signal conditioning stages.

For engineers reviewing the 1N5344E3/TR8 datasheet, 1N5344E3/TR8 pinout, 1N5344E3/TR8 application, or 1N5344E3/TR8 equivalent, key selection criteria include Zener voltage accuracy, thermal resistance (25 °C/W junction-to-lead), surge current rating (10 A), voltage regulation (ΔVZ = 0.20 V), and RoHS-compliant matte-tin plating per MIL-STD-750.

Technical Context

This device functions as a two-terminal voltage regulator operating in reverse breakdown mode. Its Zener voltage is specified at 25 °C lead temperature with 150 mA test current (IZT), and exhibits low dynamic impedance (150 Ω) ensuring stable regulation across load variations.

Thermal design relies on junction-to-lead thermal resistance of 25 °C/W at 10 mm lead length, enabling 5 W steady-state dissipation when adequately heat-sunk. The cathode band identifies polarity, and operation requires the banded end to be positive relative to the anode.

Key Specifications

Pinout & Package

Package: Axial-leaded T-18 plastic case (void-free UL94V-0 epoxy), 0.7 g weight, cathode indicated by colored band. Leads are annealed matte-tin plated for RoHS compliance and solderability per MIL-STD-750 Method 2026.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N5344B and MMSZ5231B-TP, the 1N5344E3/TR8 uniquely delivers 5 W axial-leaded regulation with RoHS compliance, making it optimal for industrial power supplies requiring high surge immunity and through-hole mounting stability.

Availability

1N5344E3/TR8 is available at Aetrix Electronics and suitable for switch-mode power supplies, overvoltage protection circuits, and analog reference designs requiring stable component supply with full traceability and long-lifecycle support.

Supply support for 1N5344E3/TR8 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 1N53xx series was engineered for ruggedized voltage regulation in harsh-environment power systems, emphasizing thermal robustness, surge resilience, and JEDEC-standardized performance across wide temperature ranges.

FAQ

What is the Zener voltage tolerance of the 1N5344E3/TR8?

The 1N5344E3/TR8 has a Zener voltage tolerance of ±5%, confirmed by its B-suffix equivalent specification in Microsemi's official datasheet. This corresponds to a regulated voltage range of 7.79 V to 8.61 V at 25 °C lead temperature with 150 mA test current. The e3 suffix indicates RoHS compliance but does not alter voltage tolerance. The 1N5344E3/TR8 maintains this tolerance across its full operating temperature range of –65 °C to +150 °C.

Can the 1N5344E3/TR8 replace the 1N5344B in existing designs?

Yes, the 1N5344E3/TR8 is a direct functional and mechanical replacement for the 1N5344B, sharing identical Zener voltage (8.2 V), tolerance (±5%), power rating (5 W), and T-18 axial package. The only difference is the RoHS-compliant matte-tin plating (e3) versus SnPb plating in the 1N5344B. The 1N5344E3/TR8 supports lead-free reflow profiles and meets IPC/JEDEC J-STD-020B Level 1 moisture sensitivity-no PCB layout or thermal design changes are needed.

What is the maximum surge current rating for the 1N5344E3/TR8?

The 1N5344E3/TR8 has a maximum non-repetitive surge current (I_ZSM) of 10 A, defined as the peak value of an 8.3 ms half-sine waveform. This rating is verified per Microsemi's datasheet and enables reliable transient suppression in power rails subject to load dump or inductive switching events. Derating is not required for single-event surges within this limit, and the 1N5344E3/TR8 retains regulation integrity after such events when operated within its thermal limits.

How does the thermal resistance of the 1N5344E3/TR8 affect PCB layout?

With a junction-to-lead thermal resistance of 25 °C/W at 10 mm lead length, the 1N5344E3/TR8 requires adequate copper mass on the PCB to dissipate 5 W continuously. For FR4 boards with 1 oz Cu, Microsemi specifies 4 mm² copper pads and 1 mm track width over 25 mm length to achieve 85 °C/W junction-to-ambient. To maintain full 5 W rating, leads should extend ≥10 mm from the body and be soldered to large thermal pads-direct placement near heat-generating components without thermal relief is discouraged for sustained operation.

Is the 1N5344E3/TR8 suitable for automotive under-hood applications?

Yes, the 1N5344E3/TR8 is rated for –65 °C to +150 °C operating and storage temperatures and features moisture sensitivity Level 1 (no dry pack required), nonsensitivity to ESD per MIL-STD-750 Method 1020, and robust surge capability-key requirements for automotive under-hood use. Its UL94V-0 epoxy body and matte-tin plating ensure reliability in high-vibration, high-humidity environments. The 1N5344E3/TR8 is commonly deployed in engine control unit (ECU) power conditioning and battery monitoring circuits where thermal and transient resilience are critical.