Microchip Technology 1N5370/TR12

Overview

1N5370/TR12 from Microsemi is a 5 W axial-leaded silicon Zener diode with nominal regulation voltage of 56 V, ±5% tolerance (B suffix), 20 mA test current, 35 Ω dynamic impedance at IZT, and maximum reverse leakage of 0.5 μA at 42.6 V. It regulates voltage in power supply reference and overvoltage protection circuits across industrial temperature range.

For engineers reviewing the 1N5370/TR12 datasheet, 1N5370/TR12 pinout, 1N5370/TR12 application, or 1N5370/TR12 equivalent, key selection criteria include Zener voltage accuracy, thermal resistance (25 °C/W junction-to-lead), surge current rating (280 A), voltage regulation (ΔVZ = 1.00 V), and RoHS-compliant e3 marking compatibility.

Technical Context

This device operates as a two-terminal voltage reference, conducting in reverse breakdown to maintain stable output voltage under varying load and line conditions. Its low dynamic impedance (35 Ω) ensures minimal voltage deviation across 10–50% of IZM, and its 25 °C/W thermal resistance enables reliable 5 W dissipation with 3/8″ lead length heat sinking.

The 1N5370/TR12 exhibits tight voltage regulation (ΔVZ = 1.00 V), withstands 8.3 ms non-repetitive surge currents up to 280 A, and maintains ≤0.5 μA reverse leakage at VR = 42.6 V - critical for precision biasing and low-power standby regulation.

Key Specifications

Pinout & Package

Package: T-18 axial-leaded plastic encapsulated case per JEDEC DO-204AL; void-free UL94V-0 epoxy body; cathode indicated by band; leads plated with annealed matte tin (RoHS compliant); weight 0.7 g.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N5370B and MMBZ5255B, the 1N5370/TR12 uniquely combines JEDEC-standard axial packaging, 5 W continuous power, 25 °C/W thermal resistance, and tape-and-reel delivery - making it optimal for high-reliability industrial power supplies requiring manual or wave-solder assembly with assured long-term availability.

Availability

1N5370/TR12 is available at Aetrix Electronics and suitable for industrial power supplies, telecom surge protection circuits, and sensor excitation modules requiring stable component supply with RoHS compliance and JEDEC-standard mechanical form factor.

Supply support for 1N5370/TR12 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 1N53xxB series was designed for robust voltage regulation in harsh-environment power systems, emphasizing thermal stability, surge resilience, and long-term parametric consistency under extended temperature cycling.

FAQ

What is the Zener voltage tolerance of the 1N5370/TR12?

The 1N5370/TR12 has a ±5% Zener voltage tolerance, confirmed by the "B" suffix in its full designation per Microsemi's datasheet. This means its regulated voltage falls within 53.2 V to 58.8 V at 20 mA test current and 25 °C lead temperature. The tolerance is guaranteed across the full operating temperature range (-65 °C to +150 °C) and applies to every unit shipped, not just typical values.

Does the 1N5370/TR12 require dry packing for moisture sensitivity?

No, the 1N5370/TR12 does not require dry packing because it carries IPC/JEDEC J-STD-020B moisture sensitivity Level 1 classification. This is explicitly stated in the Microsemi datasheet and verified by its void-free thermosetting epoxy encapsulation. As a result, the 1N5370/TR12 can be stored indefinitely at ambient conditions without baking prior to soldering.

What is the maximum steady-state power dissipation for the 1N5370/TR12 on a standard FR4 PCB?

The 1N5370/TR12 delivers 1.47 W steady-state power on an FR4 PCB (1 oz Cu) with 4 mm² copper pads and 1 mm track width, per its 85 °C/W junction-to-ambient thermal resistance. This value is specified in the "Maximum Ratings" table and assumes TA = 25 °C ambient. Derating is required above 25 °C, following the curve in Figure 1 of the official datasheet.

Can the 1N5370/TR12 be used as a direct replacement for the 1N5370B in existing designs?

Yes, the 1N5370/TR12 is electrically and mechanically identical to the 1N5370B except for packaging: both share identical Zener voltage (56 V ±5%), dynamic impedance (35 Ω), thermal resistance (25 °C/W), and all other electrical parameters. The "TR12" suffix only denotes EIA-296 tape-and-reel packaging - no PCB layout or schematic changes are needed when substituting 1N5370/TR12 for 1N5370B.

What is the reverse leakage current specification for the 1N5370/TR12?

The 1N5370/TR12 has a maximum reverse leakage current (IR) of 0.5 μA, measured at a reverse test voltage (VR) of 42.6 V - which is 75% of its nominal Zener voltage. This value is guaranteed across the full temperature range and is critical for low-power biasing applications where leakage-induced error must remain below 1 μA.