Diodes Incorporated 1N4747A-T

Overview

1N4747A-T from Diodes Incorporated is a 1.0 W, 20 V nominal Zener diode in DO-41 glass package with ±5% voltage tolerance, 22 Ω maximum Zener impedance at 12.5 mA test current, and -65°C to +175°C operating temperature range, used for precision voltage regulation in power supply feedback loops and overvoltage protection circuits.

For engineers reviewing the 1N4747A-T datasheet, 1N4747A-T pinout, 1N4747A-T application, or 1N4747A-T equivalent, key selection criteria include Zener voltage stability under varying load/temperature, thermal resistance (175 °C/W), surge current rating (225 mA for 8.3 ms), and RoHS-compliant Sn96.5Ag3.5 termination.

Technical Context

This discrete Zener diode operates in reverse breakdown mode to maintain stable reference voltage across its cathode–anode terminals. It delivers regulated output at 20 V with 12.5 mA test current and exhibits a positive temperature coefficient (+0.06 to +0.09 %/°C) ensuring predictable drift behavior in temperature-varying environments.

Its DO-41 glass package provides hermetic sealing and UL 94V-0 flammability rating, while the 0.35 g mass and defined lead geometry support manual and automated through-hole assembly. Thermal derating begins above 50°C at 6.67 mW/°C when leads are held at 50°C with 9.5 mm length from case.

Key Specifications

Pinout & Package

DO-41 glass axial package with cathode band marking; body diameter 2.60 mm max, overall length 26.0 mm min, weight ≈ 0.35 g.

Key Features

Applications

Equivalent & Alternatives

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

Compared with DFLZ20-7 and 1N4747A-A, the 1N4747A-T offers identical Zener performance in tape-and-reel format but lacks long-term reliability validation and SMT compatibility-making it suitable only for legacy through-hole production or repair.

Availability

1N4747A-T is available at Aetrix Electronics and suitable for switch-mode power supplies, industrial sensor references, overvoltage clamp protection, and microcontroller reset circuits requiring stable component supply and full traceability.

Supply support for 1N4747A-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, headquartered in Plano, Texas, with design, manufacturing, and sales operations across Asia, Europe, and North America.

The 1N47xxA series belongs to Diodes' standard Zener diode product line, engineered for general-purpose voltage regulation and protection in cost-sensitive, high-volume industrial and consumer power systems.

FAQ

What is the maximum steady-state power dissipation for 1N4747A-T at 70°C ambient?

At 70°C ambient, the 1N4747A-T must be derated from its 1.0 W rating at 25°C. With a derating factor of 6.67 mW/°C above 50°C, power drops to 1.0 W − (20°C × 6.67 mW/°C) = 866.6 mW. This assumes leads are held at 50°C with 9.5 mm length from case per datasheet Note 1.

Is 1N4747A-T suitable for automotive under-hood applications?

Yes-the device is rated for −65°C to +175°C operating temperature and uses UL 94V-0 glass encapsulation, meeting under-hood thermal and flammability requirements. However, Diodes Incorporated explicitly states it is "NOT RECOMMENDED FOR NEW DESIGN," so AEC-Q200-qualified alternatives like DFLZ20-7 should be evaluated for new automotive projects.

How does the +0.06 to +0.09 %/°C temperature coefficient affect circuit accuracy?

Over a 100°C range (e.g., −40°C to +60°C), the Zener voltage shifts by 0.6–0.9%, or ±120–180 mV from 20 V. In precision references, this requires compensation via resistor networks or selection of tighter-tolerance units; it is acceptable for non-critical clamping where ±1 V margin exists.

What is the meaning of the "-T" suffix in 1N4747A-T?

The "-T" suffix denotes tape-and-reel packaging: DO-41 devices supplied in 5,000-unit reels compatible with automated SMT placement equipment. It shares identical electrical and thermal specifications with the "-A" (ammo pack) variant-only packaging and handling differ.