Microchip Technology 1N4758CP/TR8

Overview

1N4758CP/TR8 from Microsemi is a 1.0 W axial-lead silicon Zener diode with nominal zener voltage 56 V, ±5% tolerance (A suffix), plastic DO-41 package, and tape-and-reel packaging (TR8). It regulates voltage across wide current and temperature ranges (-65°C to +150°C), with 4.5 mA test current, 110 Ω dynamic impedance at I_ZT, and 2000 mA maximum surge current. It is used in power supply overvoltage clamping and reference voltage generation.

For engineers reviewing the 1N4758CP/TR8 datasheet, 1N4758CP/TR8 pinout, 1N4758CP/TR8 application, or 1N4758CP/TR8 equivalent, key selection criteria include zener voltage accuracy, thermal resistance (45°C/W junction-to-lead), steady-state power rating (1.0 W at T_L < 105°C), reverse leakage (<5 µA at 42.6 V), and RoHS-compliant matte-tin plating.

Technical Context

This device operates in reverse breakdown to maintain stable voltage under varying load and line conditions. Its 56 V zener voltage is specified at 4.5 mA test current with 110 Ω dynamic impedance, ensuring predictable regulation slope near the knee. Temperature coefficient is positive and ~35 mV/°C per Figure 3, requiring derating above 25°C ambient per the published power curve.

It features a void-free thermosetting epoxy case rated UL94V-0, tin-lead or RoHS-compliant matte-tin terminals, cathode band polarity marking, and moisture sensitivity level 1 (no dry pack required). Thermal resistance is 45°C/W junction-to-lead at 10 mm lead length, or 105°C/W junction-to-ambient on FR4 with defined copper pad geometry.

Key Specifications

Pinout & Package

DO-41 (JEDEC DO-204AL) plastic axial-lead package with cathode indicated by color band; leads are tin-lead or RoHS-compliant matte-tin plated, solderable 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 1N4758A and BZX85C56, the 1N4758CP/TR8 offers JEDEC-standardized performance, optimized thermal resistance for lead-conducted cooling, and verified tape-and-reel compatibility for high-throughput assembly-making it the preferred choice for production-grade 56 V Zener regulation.

Availability

1N4758CP/TR8 is available at Aetrix Electronics and suitable for power supply clamping, voltage reference generation, automotive load-dump suppression, and industrial I/O protection requiring stable component supply across extended temperature and surge conditions.

Supply support for 1N4758CP/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, RF, and discrete components for aerospace, defense, and industrial markets.

The 1N47xxAP series was designed specifically for robust, standardized Zener regulation in mission-critical power systems where JEDEC compliance, thermal stability, and long-term parametric consistency are mandatory.

FAQ

What is the zener voltage tolerance of the 1N4758CP/TR8?

The 1N4758CP/TR8 has a nominal zener voltage of 56 V with ±5% tolerance, indicated by the "A" suffix in the part number per Microsemi's documentation. This tolerance applies at 4.5 mA test current and 25°C lead temperature. The "P" denotes plastic DO-41 packaging, and "TR8" specifies 8 mm tape-and-reel format. No tighter tolerance (e.g., ±2% or ±1%) is specified for this variant.

Does the 1N4758CP/TR8 meet RoHS requirements?

Yes, the 1N4758CP/TR8 is RoHS compliant, as confirmed by the "e3" designation in Microsemi's official documentation. It uses annealed matte-tin plating on terminals instead of tin-lead, satisfying EU Directive 2011/65/EU. The device carries no lead content exemptions and is rated for moisture sensitivity level 1, eliminating dry-pack requirements prior to assembly.

What is the maximum surge current rating for the 1N4758CP/TR8?

The 1N4758CP/TR8 is rated for a maximum surge current (I_SM) of 2000 mA, measured using a ½-sine wave pulse of 1/120 second duration at 25°C ambient. This rating enables reliable transient suppression in applications such as automotive load-dump events or power supply turn-on surges, provided the average power remains within the 1.0 W steady-state limit.

How does thermal resistance differ between junction-to-lead and junction-to-ambient for the 1N4758CP/TR8?

The 1N4758CP/TR8 has a junction-to-lead thermal resistance of 45°C/W at 10 mm lead length, optimized for heat conduction through leads. In contrast, its junction-to-ambient resistance is 105°C/W when mounted on FR4 with specified copper pads (4 mm²) and trace geometry. This difference confirms that effective thermal design must prioritize lead termination rather than PCB copper area alone.

Can the 1N4758CP/TR8 be used as a direct replacement for the 1N4758A in existing designs?

Yes, the 1N4758CP/TR8 is electrically and mechanically identical to the 1N4758A except for packaging: both share the same DO-41 outline, 56 V ±5% zener voltage, 1.0 W rating, and thermal specifications. The "CP/TR8" suffix adds RoHS-compliant plating and tape-and-reel delivery-making it a drop-in replacement for automated assembly, while retaining full compatibility with legacy 1N4758A footprints and schematics.