Microchip Technology 1N4748P/TR12

Overview

1N4748P/TR12 from Microsemi is a 22 V, 1 W axial-lead Zener diode in DO-41 plastic package with ±5% voltage tolerance, 11.5 mA test current, and 23 Ω dynamic impedance at I_ZT, used for precision voltage regulation in power supply reference and overvoltage protection circuits.

For engineers reviewing the 1N4748P/TR12 datasheet, 1N4748P/TR12 pinout, 1N4748P/TR12 application, or 1N4748P/TR12 equivalent, key selection criteria include Zener voltage accuracy, thermal resistance (45 °C/W junction-to-lead), surge current rating (205 mA), reverse leakage (<5 µA at 16.7 V), and RoHS-compliant "e3" plating option availability.

Technical Context

The 1N4748P/TR12 operates as a two-terminal voltage reference device, conducting in reverse breakdown to maintain stable 22 V across its terminals within specified current limits (IZK = 0.25 mA, IZM = 205 mA at TA = 50 °C). Its DO-41 plastic package delivers lower thermal resistance than glass-body variants, enabling higher power reliability at elevated ambient temperatures.

It exhibits a positive temperature coefficient near 22 V (≈+5.5 mV/°C per Figure 3), requires cathode-band orientation for correct biasing, and complies with IPC/JEDEC J-STD-020B Level 1 moisture sensitivity-no dry pack required. Forward voltage is ≤1.2 V at 200 mA.

Key Specifications

Pinout & Package

DO-41 (DO-204AL) plastic axial-leaded package: void-free thermosetting epoxy body (UL94V-0), tin-lead or RoHS-compliant matte-tin plating, cathode indicated by color band. Weight: 0.7 g.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N4748A and MMSZ4702T1G, the 1N4748P/TR12 offers superior thermal performance in through-hole applications, full legacy compatibility with JEDEC 1N47xxA footprints, and dual plating options-making it optimal for industrial power supplies requiring long-term reliability and serviceability.

Availability

1N4748P/TR12 is available at Aetrix Electronics and suitable for industrial power supplies, analog instrumentation, overvoltage protection circuits, and embedded control systems requiring stable component supply and long-lifecycle support.

Supply support for 1N4748P/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, RF, and timing solutions for aerospace, defense, and industrial markets.

The 1N47xxA Zener series was designed for robust, cost-effective voltage regulation in mission-critical power and signal conditioning applications where thermal stability and JEDEC interoperability are essential.

FAQ

What is the Zener voltage tolerance of the 1N4748P/TR12?

The 1N4748P/TR12 has a nominal Zener voltage of 22 V with a tolerance of ±5%, as indicated by the "A" suffix in its JEDEC designation. This tolerance is guaranteed at 11.5 mA test current and 25 °C lead temperature. The "P" denotes plastic DO-41 packaging, and "TR12" specifies tape-and-reel packaging per EIA-296 standard. The 1N4748P/TR12 maintains this specification across its qualified operating temperature range.

Does the 1N4748P/TR12 require moisture preconditioning before reflow soldering?

No, the 1N4748P/TR12 is rated IPC/JEDEC J-STD-020B Level 1 for moisture sensitivity, meaning it may be stored and assembled without dry packing or baking. Its void-free thermosetting epoxy body and Level 1 classification eliminate moisture-related popcorning risk during standard reflow profiles. This simplifies manufacturing flow and reduces process overhead compared to higher-level moisture-sensitive devices. The 1N4748P/TR12 is fully compatible with standard Sn/Pb and lead-free soldering processes up to 260 °C for 10 seconds.

What is the maximum surge current rating for the 1N4748P/TR12?

The 1N4748P/TR12 has a maximum non-repetitive surge current (I_SM) of 205 mA, measured using a ½-sine wave pulse of 1/120 second duration at 25 °C ambient. This rating applies under specified test conditions and reflects the device's ability to absorb transient energy without parametric shift or failure. Engineers must ensure external current-limiting resistors and layout minimize peak power dissipation during surges. The 1N4748P/TR12 leverages its 1 W steady-state rating and low thermal resistance to sustain repeated surges within datasheet limits.

How does the thermal resistance of the 1N4748P/TR12 compare to glass-body versions?

The 1N4748P/TR12 has a junction-to-lead thermal resistance of 45 °C/W at 3/8″ (10 mm) lead length, which is significantly lower than the 105 °C/W junction-to-ambient rating typical of glass-body 1N4748A (DO-35) devices on FR4 board. This 57% improvement in thermal path efficiency allows the 1N4748P/TR12 to operate at higher ambient temperatures or deliver more reliable regulation under sustained load. The plastic P-suffix construction directly enables this advantage, making the 1N4748P/TR12 preferable for thermally demanding applications.

Is the 1N4748P/TR12 RoHS compliant?

Yes, the 1N4748P/TR12 is available in RoHS-compliant configuration with "e3" suffix (e.g., 1N4748P-e3/TR12), featuring annealed matte-tin plating per MIL-STD-750 Method 2026. Standard production uses RoHS-compliant terminations unless otherwise specified. The device meets EU Directive 2011/65/EU requirements with no lead, mercury, cadmium, hexavalent chromium, PBB, or PBDE. The 1N4748P/TR12 retains full electrical and mechanical equivalence to non-RoHS versions, ensuring seamless transition in existing designs.