onsemi 1N5224B

Overview

1N5224B from Fairchild Semiconductor is a 2.8 V ±5% Zener diode in DO-35 glass package, rated for 500 mW power dissipation at 25°C, with 30 Ω dynamic impedance at 20 mA test current and -0.080 %/°C temperature coefficient - used for precision voltage reference and low-power regulation in sensor biasing and analog front-end circuits.

For engineers reviewing the 1N5224B datasheet, pinout, applications, or equivalent options, this page delivers verified electrical characteristics, thermal derating behavior, cathode identification, and direct alternatives for low-voltage Zener reference design.

Technical Context

The 1N5224B operates as a two-terminal silicon Zener diode optimized for stable reverse-breakdown regulation at nominal 2.8 V. It achieves specified V_Z tolerance (±5%) under thermal equilibrium conditions at 30°C lead temperature with 3/8″ lead length, per JEDEC DO-204AH standard.

Its Zener voltage exhibits a negative temperature coefficient of -0.080 %/°C, indicating decreasing breakdown voltage with rising junction temperature - critical for ambient-compensated reference designs where thermal drift must be modeled or offset.

Key Specifications

Pinout & Package

DO-35 glass package: axial-leaded, hermetically sealed, cathode identified by color band. Total length 4.56 mm, body diameter 1.91 mm, lead diameter 0.46 mm, weight 0.137 g.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N5224B, the 1N4728A offers higher voltage headroom but shifts reference by +0.5 V, while BZX55C2V7 trades 0.1 V lower V_Z for marginally better temperature stability at the cost of increased dynamic impedance - both require validation against load regulation and thermal drift requirements.

Availability

1N5224B is available at Aetrix Electronics and suitable for temperature sensor biasing, microcontroller reset generation, ADC reference scaling, and LED current regulation requiring stable component supply and traceable sourcing.

Supply support for 1N5224B 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

Fairchild Semiconductor was a U.S.-based semiconductor company specializing in power management, signal conditioning, and discrete components before its acquisition by ON Semiconductor in 2016.

The 1N52xxB series was designed as a general-purpose, low-power Zener reference family targeting cost-sensitive industrial and consumer analog circuits requiring stable voltage regulation below 5 V.

FAQ

What is the nominal Zener voltage of the 1N5224B and how is it tested?

The 1N5224B has a nominal Zener voltage of 2.8 V, with a guaranteed range of 2.66 V to 2.94 V at 20 mA test current. It is measured under thermal equilibrium conditions at 30°C ±1°C lead temperature with 3/8″ lead length, per the Fairchild datasheet Rev. 4.10. This ensures repeatable V_Z characterization independent of transient self-heating effects. The 1N5224B specification strictly follows JEDEC DO-204AH standards for low-voltage Zener diodes.

Does the 1N5224B have a defined forward voltage, and what is its value?

Yes, the 1N5224B specifies a maximum forward voltage (V_F) of 1.2 V at 200 mA forward current. This parameter is relevant for verifying device polarity during board-level testing and for modeling conduction paths in bidirectional ESD protection schemes. The 1N5224B's low V_F supports reliable anode-cathode identification and aids in functional safety checks during manufacturing test.

How does the temperature coefficient affect the 1N5224B's performance in varying ambient conditions?

The 1N5224B has a temperature coefficient of -0.080 %/°C, meaning its Zener voltage decreases by approximately 2.24 mV/°C around 2.8 V. Over a -40°C to +85°C ambient range, this results in ~280 mV total drift. Designers must account for this in precision references; the 1N5224B is best suited for applications where such drift is acceptable or compensated. The 1N5224B's TC is confirmed in the Electrical Characteristics table on page 2 of the official datasheet.

What is the maximum power dissipation of the 1N5224B and how does it change with temperature?

The 1N5224B has a maximum power dissipation of 500 mW at 25°C ambient, derating linearly at 4.0 mW/°C above 50°C. At 75°C ambient, its usable power drops to 400 mW; at 125°C, it falls to 200 mW. This derating curve is defined in the Absolute Maximum Ratings table and directly impacts thermal design - PCB copper area, airflow, and adjacent heat sources must be evaluated to maintain junction temperature within -65°C to +200°C limits. The 1N5224B's thermal behavior is fully documented in the January 2016 revision of its datasheet.

Is the 1N5224B suitable for automotive applications?

No, the 1N5224B is not qualified for automotive use. Per Fairchild's Authorized Use policy, this device is a commercial-grade part intended for non-safety-critical applications. It lacks AEC-Q101 qualification, extended temperature screening, and automotive-specific reliability testing. For automotive systems, designers must select AEC-Q101-qualified Zener diodes with appropriate PPAP documentation. The 1N5224B datasheet explicitly restricts use in transportation, aerospace, and life-critical medical equipment unless written approval is obtained.