Taiwan Semiconductor Corporation 1N4749A

Overview

1N4749A from Taiwan Semiconductor is a 1 W, 24 V ±5% Zener diode in DO-41 package, designed for voltage regulation and overvoltage protection in DC power supplies and reference circuits. It delivers nominal zener voltage of 24 V at 25 mA test current, with dynamic impedance of 10.5 Ω and maximum leakage current of 5 μA at 18.2 V.

For engineers reviewing the 1N4749A datasheet, 1N4749A pinout, 1N4749A application, or 1N4749A equivalent, this device serves as a precision, low-inductance, glass-passivated Zener for stable shunt regulation in industrial power rails, automotive subsystems, and analog reference designs where thermal stability (−55°C to +150°C junction range) and AEC-Q101 qualification options are critical.

Technical Context

The 1N4749A operates as a single-die, silicon planar Zener diode with glass-passivated junction, enabling stable reverse-breakdown behavior under controlled test conditions (IZT = 25 mA, TL = 30°C ±1°C). Its 10.5 Ω zener impedance at IZT and 750 Ω at IZK (1 mA) supports tight regulation across load transients.

Thermal performance is defined by a 150°C max junction temperature, 6.67 mW/°C derating above 50°C on 5 mm × 5 mm Cu pad, and junction-to-lead thermal resistance dependent on lead length - confirming its suitability for through-hole mounted, thermally constrained PCB layouts.

Key Specifications

Pinout & Package

Package: DO-204AL (DO-41), axial-leaded, glass-passivated, RoHS-compliant, halogen-free molding compound (UL 94V-0), pure tin-plated leads.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ON Semiconductor's 1N4749A and Vishay's BZX55-C24, the Taiwan Semiconductor 1N4749A offers superior power handling (1 W vs. 500 mW) and lower dynamic impedance (10.5 Ω vs. 12–15 Ω), making it optimal for high-stability, medium-power shunt regulation where thermal margin and ripple rejection are design priorities.

Availability

1N4749A is available at Aetrix Electronics and suitable for industrial power supplies, automotive ECUs, test equipment calibration, and telecom surge protection requiring stable component supply with consistent DO-41 form factor and AEC-Q101-qualified variants.

Supply support for 1N4749A 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

Taiwan Semiconductor Corporation (TSC) is a vertically integrated semiconductor manufacturer specializing in discrete power devices, analog ICs, and protection components, with global distribution and AEC-Q101 qualification capabilities.

The 1N4740A–1M200Z Zener series was developed to deliver cost-effective, high-reliability voltage regulation across 10–200 V ranges for industrial, automotive, and consumer power systems - emphasizing thermal robustness, low leakage, and JEDEC-standard surge resilience.

FAQ

What is the nominal zener voltage and tolerance of the 1N4749A?

The 1N4749A has a nominal zener voltage of 24 V with a standard tolerance of ±5%, meaning its guaranteed breakdown voltage range is 22.8 V to 25.2 V when tested at 25 mA and 30°C lead temperature. This tolerance is defined per JEDEC registration and applies to all units in the 1N47xxA family unless otherwise specified. The 1N4749A achieves this specification using a glass-passivated silicon junction for process consistency.

Does the 1N4749A have AEC-Q101 qualification?

Yes - an AEC-Q101 qualified version of the 1N4749A is available, designated with an "H" suffix (e.g., 1N4749AH). This variant undergoes stress testing per AEC-Q101 standards including temperature cycling, highly accelerated life testing, and mechanical shock, making it suitable for automotive under-hood applications. The base 1N4749A is not automatically qualified; only explicitly marked "H" parts carry AEC-Q101 certification.

What is the maximum surge current rating for the 1N4749A?

The 1N4749A supports a non-repetitive peak reverse surge current of 190 A for a pulse duration of 1/120 second (≈8.3 ms), per JEDEC registration. This rating assumes a half-sine or equivalent waveform and is validated under standardized test conditions. Actual surge capability may vary with PCB layout, heatsinking, and pulse repetition rate - always consult Figure 11 in the official Taiwan Semiconductor datasheet for derating guidance.

How does the 1N4749A's zener impedance affect regulation performance?

The 1N4749A exhibits a zener impedance (Z_ZT) of 10.5 Ω at 25 mA, which directly determines how much the output voltage varies with changes in current. For example, a ±10 mA load step causes ≈±105 mV deviation - critical for precision references. Lower Z_ZT improves regulation fidelity, especially in feedback loops of switching regulators where the 1N4749A is often used as a secondary clamp or reference.

Can the 1N4749A be used in surface-mount designs?

No - the 1N4749A is exclusively offered in the axial DO-204AL (DO-41) through-hole package, with no SMD variant in the official Taiwan Semiconductor product stack. Designers requiring surface-mount Zener functionality must select alternatives such as the SMAJ24A (TVS) or BZX84-C24 (SOT-23), but these differ electrically and mechanically from the 1N4749A. The 1N4749A requires plated-through-hole mounting and lead-forming per datasheet mechanical drawings.