Microchip Technology 1N4757AP/TR12

Overview

1N4757AP/TR12 from Microsemi is a 1.0 W axial-lead silicon Zener diode with nominal zener voltage of 51 V, ±5% tolerance (A suffix), 5.0 mA test current (IZT), 95 Ω dynamic impedance at IZT, and maximum reverse current of 5 μA at 38.8 V. It operates from –65 °C to +150 °C and is used for precision voltage regulation in power supply reference circuits, overvoltage protection clamps, and analog signal conditioning stages.

For engineers reviewing the 1N4757AP/TR12 datasheet, 1N4757AP/TR12 pinout, 1N4757AP/TR12 application, or 1N4757AP/TR12 equivalent, key selection criteria include its DO-41 package thermal resistance (45 °C/W junction-to-lead), 1.2 V forward voltage at 200 mA, RoHS-compliant "e3" plating option, and compatibility with tape-and-reel automated assembly (TR12 designation).

Technical Context

This device functions as a two-terminal voltage reference by operating in reverse breakdown mode, where it maintains stable 51 V regulation across a wide current range (0.25 mA to 90 mA). Its sharp knee characteristic-verified via dual-point Zener impedance measurement per Note 2-is enabled by controlled doping and plastic encapsulation that ensures low thermal resistance and moisture immunity (IPC/JEDEC J-STD-020B Level 1).

The 1N4757AP/TR12 exhibits a negative temperature coefficient typical of mid-voltage Zeners (~–2 mV/°C near 51 V), and its 1.0 W power rating is derated linearly above 105 °C lead temperature or 45 °C ambient on FR4 PCBs-critical for thermal design in compact power supplies and industrial control modules.

Key Specifications

Pinout & Package

Package: DO-41 (DO-204AL) axial-lead plastic case, 0.7 g weight, UL94V-0 epoxy body, cathode indicated by band. Tin-lead or RoHS-compliant matte-tin plating.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N4757A and MMSZ5254B-TP, the 1N4757AP/TR12 uniquely combines 1.0 W dissipation, DO-41 mechanical robustness, tape-and-reel readiness, and full RoHS compliance-making it optimal for industrial power supply and protection designs requiring proven reliability and assembly scalability.

Availability

1N4757AP/TR12 is available at Aetrix Electronics and suitable for industrial power supplies, overvoltage protection circuits, and analog sensor biasing applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant manufacturing.

Supply support for 1N4757AP/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 1N4757AP/TR12 belongs to Microsemi's legacy 1N47xxAP Zener diode family, engineered for stable voltage regulation in harsh-environment power systems where thermal resilience, ESD immunity, and JEDEC-standard consistency are critical.

FAQ

What is the Zener voltage tolerance of the 1N4757AP/TR12?

The 1N4757AP/TR12 has a nominal Zener voltage of 51 V with ±5% tolerance, as indicated by the "A" suffix in its part number per JEDEC standard. This means the actual measured V_Z at 5.0 mA test current falls between 48.45 V and 53.55 V at 25 °C lead temperature. The tolerance remains valid across the full operating temperature range of –65 °C to +150 °C, though voltage drift due to temperature coefficient must be accounted for in precision designs.

Does the 1N4757AP/TR12 meet RoHS requirements?

Yes, the 1N4757AP/TR12 is RoHS compliant, as confirmed by the "e3" suffix in its full ordering designation (1N4757AP/TR12-e3 per Microsemi documentation). It uses annealed matte-tin plating instead of tin-lead, satisfying EU Directive 2011/65/EU and related global environmental regulations. The plastic DO-41 package also complies with UL94V-0 flammability standards.

What is the maximum surge current rating for the 1N4757AP/TR12?

The 1N4757AP/TR12 has a maximum non-repetitive reverse surge current (I_SM) of 90 mA, measured using a ½ sine-wave pulse of 1/120 second duration at 25 °C ambient. This rating applies only to short-duration transients and must be derated for repeated surges or elevated temperatures. Continuous regulation current (I_ZM) at 50 °C is 90 mA, aligning with the surge limit under defined test conditions.

Can the 1N4757AP/TR12 be used in surface-mount designs?

No-the 1N4757AP/TR12 is an axial-lead DO-41 package and is not compatible with surface-mount assembly. For SMT equivalents, Microsemi offers the SMAJ4757A and MLL4757A families, while third-party alternatives like the MMSZ5254B-TP provide 51 V regulation in SOD-123 packages. Substituting requires PCB redesign, thermal validation, and verification of surge current capability.

What does the "TR12" suffix indicate in 1N4757AP/TR12?

The "TR12" suffix denotes tape-and-reel packaging per EIA-296 standard, with 12 mm tape width and component spacing optimized for high-speed pick-and-place machines. This configuration enables automated assembly without manual handling, reduces contamination risk, and supports traceability via reel labeling. The base part 1N4757AP remains electrically and thermally identical-only the packaging format differs.