Diodes Incorporated 1N4745A-T

Overview

1N4745A-T from Diodes Incorporated is a 1.0W, 16V ±5% tolerance Zener diode in DO-41 glass package, rated for 15.5mA test current, 16Ω maximum Zener impedance at IZT, and -65°C to +175°C operating temperature range. It provides precise voltage regulation in low-power reference and protection circuits, such as power supply feedback loops and overvoltage clamp stages.

For engineers reviewing the 1N4745A-T datasheet, 1N4745A-T pinout, 1N4745A-T application, or 1N4745A-T equivalent, key selection criteria include nominal Zener voltage (16V), power dissipation (1.0W), thermal resistance (175°C/W), Zener impedance (16Ω max), and DO-41 mechanical compatibility with through-hole PCB layouts.

Technical Context

This Zener diode operates in reverse breakdown mode to maintain stable voltage across its terminals under varying load or line conditions. Its 16V nominal Zener voltage is specified at 15.5mA test current (IZT), with a sharp knee characterized by 16Ω dynamic impedance (ZZT) and 700Ω maximum knee impedance (ZZK) at 0.25mA.

Designed for DC voltage reference and transient suppression, it exhibits a positive temperature coefficient (+0.055 to +0.09%/°C), enabling predictable drift behavior in temperature-sensitive analog circuits. The DO-41 glass package ensures hermetic sealing, UL 94V-0 flammability rating, and compatibility with standard wave-soldering processes.

Key Specifications

Pinout & Package

DO-41 glass axial package with cathode band marking; leads are Sn96.5Ag3.5 solderable per MIL-STD-202, Method 208. Polarity is unambiguous: banded end is cathode.

Key Features

Applications

Availability

1N4745A-T is available at Aetrix Electronics and suitable for power supply feedback reference, overvoltage clamp protection, and low-power sensor biasing requiring stable component supply and long-term obsolescence mitigation planning.

Supply support for 1N4745A-T 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, specializing in high-reliability, cost-optimized components for industrial, computing, and consumer applications.

The 1N47xxA series belongs to Diodes' legacy Zener diode product line, engineered for general-purpose voltage regulation and protection in cost-sensitive, high-volume applications with proven field reliability.

FAQ

What is the difference between 1N4745A-T and 1N4745A-A?

The suffix "-T" denotes tape-and-reel packaging (5,000 units per reel), optimized for automated SMT placement despite being a through-hole device; "-A" indicates ammo pack (5,000 units per tube), intended for manual or wave-solder assembly. Both share identical electrical and thermal specifications, DO-41 package dimensions, and marking.

Is 1N4745A-T still in active production?

No - Diodes Incorporated has marked the entire 1N4728A–1N4761A series as obsolete with no alternate part offered. Aetrix Electronics maintains limited legacy stock and supports design-in continuity through controlled distribution and cross-reference guidance for functional replacements.

Can 1N4745A-T be used in surface-mount designs?

It is a DO-41 axial-leaded device and not designed for direct SMT placement. However, it can be mounted on SMT boards using through-hole pads or adapter carriers. For true SMT Zener solutions, consider Diodes' BZX84-C16 or MMBZ5245B, which offer comparable 16V regulation in SOT-23 packages.

What is the maximum allowable junction temperature for continuous operation?

The absolute maximum junction temperature is +175°C. With a thermal resistance of 175°C/W and 1.0W power dissipation, the junction-to-ambient rise is 175°C - meaning operation at full power is only possible at TA = 25°C with ideal heat sinking. Derating begins above 50°C ambient at 6.67 mW/°C.