Diodes Incorporated 1N4730A-T

Overview

1N4730A-T from Diodes Incorporated is a 1.0 W, 3.9 V ±5% Zener diode in DO-41 glass package, designed for voltage regulation and reference applications with 64 mA test current, 9.0 Ω dynamic impedance at I_ZT, and -0.07 to -0.02 %/°C temperature coefficient. It operates across -65°C to +175°C and supports low-power analog biasing in power supply feedback loops.

For engineers reviewing the 1N4730A-T datasheet, 1N4730A-T pinout, 1N4730A-T application, or 1N4730A-T equivalent, this part serves as a precision 3.9 V shunt regulator where stable reverse breakdown voltage, low Zener impedance, and predictable thermal drift are critical for feedback stability in DC-DC converters and voltage references.

Technical Context

This Zener diode functions as a two-terminal shunt voltage regulator, maintaining a nominal 3.9 V reverse breakdown voltage at 64 mA test current (I_ZT). Its negative temperature coefficient (-0.07 to -0.02 %/°C) indicates decreasing V_Z with rising temperature - a key factor when compensating for thermal drift in reference circuits.

It exhibits 9.0 Ω dynamic impedance (Z_ZT) at I_ZT and 400 Ω knee impedance (Z_ZK) at 1.0 mA, confirming sharp breakdown characteristics suitable for low-noise regulation. The device is rated for 1.0 W power dissipation at 25°C, derating linearly above 50°C at 6.67 mW/°C with leads held at 50°C at 9.5 mm from case.

Key Specifications

Pinout & Package

DO-41 glass axial package with cathode band marking; no active pinout - two-terminal device with anode and cathode leads. Polarity identified by single black band indicating cathode terminal.

Key Features

Applications

Availability

1N4730A-T is available at Aetrix Electronics and suitable for power supply feedback regulation, overvoltage clamp protection, and low-power voltage reference applications requiring stable component supply and long-term sourcing continuity.

Supply support for 1N4730A-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, industry-standard components for power management and signal integrity.

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

FAQ

What is the maximum continuous Zener current for 1N4730A-T at 25°C?

The maximum continuous Zener current is derived from P_D/V_Z = 1.0 W / 3.9 V ≈ 256 mA. However, the device is characterized at 64 mA test current (I_ZT) and rated for reliable operation up to its 1.0 W power limit with proper thermal management - sustained currents above ~100 mA require attention to ambient temperature and lead thermal relief.

How does the temperature coefficient affect circuit performance?

The -0.07 to -0.02 %/°C coefficient means V_Z decreases by approximately 0.78 to 0.22 mV per °C rise. In precision references, this drift contributes directly to output error; for example, a 50°C rise causes 1.1–3.9 mV drop in regulated voltage - acceptable in non-critical applications but requiring compensation in high-accuracy systems.

Is 1N4730A-T compatible with lead-free reflow soldering processes?

Yes - the device features Sn96.5Ag3.5 terminations and is rated for solderability per MIL-STD-202, Method 208. It supports standard lead-free reflow profiles (peak ≤260°C), and its glass DO-41 package withstands thermal cycling without cracking when mounted with appropriate pad geometry and strain relief.

Why is the 1N4730A-T marked with a cathode band instead of part number?

The DO-41 package uses a single black cathode band for polarity identification; full part-number marking is omitted due to physical size constraints. This aligns with industry-standard Zener diode marking practice - the band always denotes the cathode, ensuring correct orientation during board assembly and preventing reverse-bias failure.