onsemi 1N5344B

Overview

1N5344B from onsemi is a 5 W axial-lead Zener diode with nominal zener voltage of 8.2 V, ±5% tolerance, maximum zener impedance of 150 Ω at 1.5 mA test current, and surge rating of 580 A at 8.3 ms. It operates as a precision voltage reference or shunt regulator in DC power supply feedback paths, overvoltage protection circuits, and voltage-clamping applications.

For engineers reviewing the 1N5344B datasheet, pinout, applications, or equivalent options, this device requires attention to thermal derating above 25°C, cathode-band polarity identification, junction-to-lead thermal resistance (25°C/W), and compliance with JEDEC 5% tolerance standards for stable regulation under varying load conditions.

Technical Context

The 1N5344B uses silicon-oxide passivated junction technology to achieve tight voltage regulation and low leakage. Its zener voltage is specified at IZT = 1.5 mA with VZ ranging from 7.79 V (min) to 8.61 V (max), and it maintains regulation across ambient temperatures from −65°C to +200°C.

It features ESD robustness (>16 kV HBM), 180 W non-repetitive surge capability at 8.3 ms, and a cathode-indicated axial package (Case 017AA). The device's temperature coefficient is positive in the 8.2 V range, requiring thermal design consideration for high-stability references.

Key Specifications

Pinout & Package

Package: Axial-lead, transfer-molded plastic (Case 017AA), cathode indicated by band. Dimensions: 8.38–8.89 mm length × 3.30–3.68 mm diameter; lead diameter uncontrolled within 1.27 mm max.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N5344 and BZX85C8V2, the 1N5344B delivers higher power margin (5 W), superior surge resilience (580 A), and guaranteed ±5% tolerance in a rugged axial package-making it optimal for industrial power regulation where reliability under stress is non-negotiable.

Availability

1N5344B is available at Aetrix Electronics and suitable for industrial power supplies, automotive body control modules, and test equipment requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for 1N5344B 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

onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power, analog, sensing, and connectivity solutions for automotive, industrial, and cloud infrastructure markets.

The 1N53 Series belongs to onsemi's Surmetic™ 40 Zener regulator family, engineered for high-reliability voltage reference and clamping in harsh-environment applications demanding robust surge immunity and wide temperature operation.

FAQ

What is the zener voltage tolerance of the 1N5344B?

The 1N5344B has a guaranteed ±5% zener voltage tolerance, meaning its nominal 8.2 V rating falls between 7.79 V (minimum) and 8.61 V (maximum) at I_ZT = 1.5 mA. This tight tolerance is confirmed in the onsemi datasheet Rev. 19 and distinguishes it from the standard 1N5344 (±10%). The 1N5344B achieves this via tighter process controls on silicon-oxide passivated junctions.

Can the 1N5344B replace the 1N5344 in existing designs?

Yes, the 1N5344B is a direct drop-in replacement for the 1N5344 in most cases, sharing identical package (Case 017AA), pinout, and electrical characteristics except for tighter tolerance (±5% vs. ±10%) and Pb-free compliance. However, verify thermal layout margins since both parts share the same 25°C/W junction-to-lead resistance and 5 W rating. The 1N5344B should be preferred where RoHS compliance or tighter regulation is required.

What is the maximum surge current the 1N5344B can handle?

The 1N5344B supports a peak non-repetitive surge current of 580 A at an 8.3 ms pulse width, as specified in the onsemi datasheet. This value is derived from its 180 W surge rating and correlates to the 8.2 V zener voltage. Surge capability decreases for longer pulses per Figure 5; for example, at 100 ms, the limit drops to ~40 A. Always confirm system-level transient profiles against this rating.

How does thermal derating affect the 1N5344B's power handling?

The 1N5344B is rated for 5 W at 25°C lead temperature (T_L), with linear derating of 40 mW/°C above that point. At 75°C T_L, its usable power drops to 3 W. Effective derating requires maintaining ≥3/8″ lead length to heatsink and accounting for junction-to-lead thermal resistance (25°C/W). Exceeding derated limits risks parametric shift or permanent damage.

Is the 1N5344B suitable for low-leakage applications?

Yes-the 1N5344B specifies maximum reverse leakage current of 0.2 mA at 6.2 V (V_R), making it suitable for low-quiescent circuits such as battery-powered sensors or standby power monitors. This leakage is measured at 25°C; it increases with temperature but remains below 1 mA up to 125°C. For sub-μA leakage, consider higher-voltage Zeners or specialized low-I_R variants.