Microchip Technology 1N4737E3/TR13

Overview

1N4737E3/TR13 from Microsemi is a 1.0 W, 7.5 V ±5% silicon Zener diode in DO-41 plastic package, rated for 34 mA test current, 4.0 Ω dynamic impedance at I_ZT, and 5 μA reverse leakage at 6.0 V, used for precision voltage regulation in power supply reference and overvoltage protection circuits.

For engineers reviewing the 1N4737E3/TR13 datasheet, 1N4737E3/TR13 pinout, 1N4737E3/TR13 application, or 1N4737E3/TR13 equivalent, key selection criteria include Zener voltage tolerance, thermal resistance (45 °C/W junction-to-lead), surge current rating (605 mA), RoHS-compliant matte-tin plating, and tape-and-reel packaging per EIA-296.

Technical Context

This device operates in reverse breakdown to maintain stable output voltage across varying load and line conditions. It exhibits a sharp knee at 0.5 mA test current (Z_ZK = 4.0 Ω), with temperature coefficient near zero at 7.5 V, enabling low-drift reference design.

Designed for axial-lead mounting on FR4 PCBs with 1 oz copper, it delivers 1.0 W steady-state dissipation at T_L < 105 °C (3/8″ lead length) or T_A < 45 °C, and withstands 260 °C soldering for 10 s per MIL-STD-750.

Key Specifications

Pinout & Package

DO-41 (DO-204AL) plastic axial-leaded package with cathode indicated by band; terminals are anode and cathode only - no internal circuitry or multi-pin configuration.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N4737A and MMSZ4707T1G, the 1N4737E3/TR13 offers full 1.0 W power capability in RoHS-compliant through-hole format with superior thermal resistance and surge robustness-ideal for industrial power rails requiring reliability and process compatibility.

Availability

1N4737E3/TR13 is available at Aetrix Electronics and suitable for power supply reference, overvoltage protection, voltage monitor threshold, and current source bias applications requiring stable component supply and long-term obsolescence management.

Supply support for 1N4737E3/TR13 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) designs high-reliability analog and mixed-signal semiconductors for aerospace, defense, and industrial markets.

The 1N47xx series was developed for general-purpose, high-stability voltage regulation in ruggedized power systems where thermal resilience and long-term parametric consistency are critical.

FAQ

What is the Zener voltage tolerance of the 1N4737E3/TR13?

The 1N4737E3/TR13 has a nominal Zener voltage of 7.5 V with a ±5% tolerance, as confirmed by its "A" suffix in the base part number and documented in Microsemi's REV C datasheet. This tolerance applies at 34 mA test current and 25 °C lead temperature. The 1N4737E3/TR13 meets JEDEC registration requirements for the 1N4737A family and maintains this specification across its full operating temperature range of –65 °C to +150 °C.

Does the 1N4737E3/TR13 support lead-free assembly processes?

Yes, the 1N4737E3/TR13 features RoHS-compliant annealed matte-tin plating per MIL-STD-750 Method 2026 and is rated for 260 °C soldering at 10 s maximum-fully compatible with standard lead-free reflow profiles. The "e3" suffix explicitly denotes this RoHS compliance, distinguishing it from Sn/Pb versions like the 1N4737A. Its Level 1 moisture sensitivity eliminates dry-pack requirements, simplifying handling in automated SMT lines.

What is the maximum surge current rating for the 1N4737E3/TR13?

According to the official Microsemi datasheet, the 1N4737E3/TR13 has a maximum non-repetitive surge current (I_SM) of 605 mA, measured using a ½ sine-wave pulse of 1/120 second duration at 25 °C ambient. This rating enables reliable transient suppression in power rail protection circuits. The 1N4737E3/TR13 sustains this surge capability without parameter shift due to its 1.0 W power rating and low thermal resistance (45 °C/W junction-to-lead).

How does the thermal performance of the 1N4737E3/TR13 compare between lead and ambient mounting?

The 1N4737E3/TR13 exhibits 45 °C/W junction-to-lead thermal resistance at 3/8″ (10 mm) lead length, but de-rates to 105 °C/W junction-to-ambient when mounted on FR4 with 1 oz copper and specified pad geometry. This means effective heat removal relies heavily on lead conduction-not PCB convection-so PCB layout must prioritize short, wide traces to heatsinks or chassis. The 1N4737E3/TR13 achieves full 1.0 W dissipation only when lead temperature stays below 105 °C.

Is the 1N4737E3/TR13 suitable for precision voltage reference applications?

The 1N4737E3/TR13 provides adequate stability for moderate-precision uses-its 7.5 V Zener point has near-zero temperature coefficient and 4.0 Ω dynamic impedance-but lacks the 1% tolerance (D suffix) or low-noise construction of dedicated reference ICs. For applications demanding <0.1% accuracy or ppm/°C drift, a bandgap or buried-Zener IC is preferred. The 1N4737E3/TR13 remains optimal for cost-sensitive, robust regulation where ±5% absolute accuracy suffices.