onsemi 1N4734A

Overview

1N4734A from ON Semiconductor is a 5.6 V, 1 W silicon Zener diode in DO-41 glass package, rated for ±5% tolerance, 5 mA test current, and 45 Ω dynamic impedance at I_Z, used for precision voltage regulation and overvoltage protection in low-power DC supplies and reference circuits.

For engineers reviewing the 1N4734A datasheet, pinout, applications, or equivalent options, key selection criteria include zener voltage accuracy, power derating above 50°C, thermal resistance, leakage current at 10 V, and non-repetitive peak reverse surge capability.

Technical Context

The 1N4734A operates as a two-terminal voltage reference device with sharp reverse breakdown at nominal 5.6 V, optimized for stable regulation under fixed-current biasing. Its 45 Ω Zener impedance at 5 mA and 2 µA leakage at 10 V support tight output voltage control in feedback networks and analog references.

Designed for through-hole mounting in DO-41 package, it features a cathode band marking, -65°C to +200°C operating temperature range, and 6.67 mW/°C power derating above 50°C - enabling reliable operation in industrial ambient conditions without forced cooling.

Key Specifications

Pinout & Package

DO-41 glass axial package with cathode indicated by a single color band on the body. Two-terminal device: anode and cathode are unidirectional; polarity must be observed for proper reverse-bias operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N4734AT and BZX55C5V6, the 1N4734A offers full 1 W power handling and 810 mA surge capacity in a standard DO-41 footprint - making it optimal for industrial power rails where thermal margin and transient resilience are prioritized over miniaturization.

Availability

1N4734A is available at Aetrix Electronics and suitable for DC power supply regulation, overvoltage protection circuits, and temperature-stable reference designs requiring stable component supply and long-term lifecycle assurance.

Supply support for 1N4734A 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

ON Semiconductor is a global semiconductor manufacturer specializing in power management, analog, sensor, and discrete devices for automotive, industrial, and consumer applications.

The 1N47xxA series was developed as a standardized family of general-purpose Zener diodes targeting cost-effective, high-reliability voltage regulation in legacy and new-design power systems.

FAQ

What is the nominal Zener voltage and tolerance of the 1N4734A?

The 1N4734A has a nominal Zener voltage of 5.6 V with a tolerance of ±5%, meaning its actual breakdown voltage falls between 5.32 V and 5.88 V when tested at 5 mA. This specification is verified per ON Semiconductor's 1N4728A–1N4758A datasheet Rev. 8. The 1N4734A achieves this tolerance using process-controlled doping and wafer-level screening, ensuring consistent performance across production lots.

Can the 1N4734A be used in surface-mount designs?

No, the 1N4734A is packaged exclusively in the through-hole DO-41 axial glass case and is not compatible with surface-mount assembly processes. For SMT equivalents, consider the 1N4734AT (same electrical specs, tape-and-reel packaging) or SOD-123 variants like MMBZ5232B. The 1N4734A requires axial lead insertion and wave soldering; attempting reflow or hand-soldering without proper thermal management risks glass-body cracking.

What is the maximum allowable power dissipation for the 1N4734A at 75°C ambient?

At 75°C ambient, the 1N4734A must be derated from its 1.0 W rating at ≤50°C by 6.67 mW/°C for each degree above 50°C. That yields a reduction of 166.75 mW (25°C × 6.67 mW), resulting in a maximum allowable power dissipation of 833 mW. This derating ensures junction temperature remains within the -65°C to +200°C safe operating range. The 1N4734A's thermal design must account for this limit in enclosed or high-ambient environments.

How does the 1N4734A compare to other 5.6 V Zeners in terms of temperature coefficient?

The 1N4734A exhibits near-zero temperature coefficient around 5.6 V due to the physics of silicon Zener breakdown at this voltage - a well-documented characteristic confirmed in ON Semiconductor's application notes. Its typical TC is <10 ppm/°C over -25°C to +75°C, outperforming lower-voltage Zeners (e.g., 3.3 V) with higher negative TC or higher-voltage avalanche devices (e.g., 12 V) with positive TC. This makes the 1N4734A especially valuable in precision reference applications where thermal drift must be minimized.

Is the 1N4734A RoHS compliant and halogen-free?

Yes, the 1N4734A meets RoHS Directive 2011/65/EU requirements and is halogen-free per ON Semiconductor's material declarations. It contains no lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls (PBB), or polybrominated diphenyl ethers (PBDE). The DO-41 glass package and internal silicon die are fully compliant, and full compliance documentation is available in ON Semiconductor's "Environmental Documentation" portal. The 1N4734A is suitable for use in EU and global markets requiring environmental certification.