onsemi 1N5948B

Overview

1N5948B from ON Semiconductor is a 3 W axial-lead Zener diode with nominal zener voltage of 91 V, maximum zener impedance of 4.1 Ω at 200 mA test current, and reverse leakage current ≤0.25 μA at 69.2 V. It operates across −65°C to +200°C and is used for precision voltage regulation in power supply feedback loops, overvoltage protection circuits, and reference voltage generation.

For engineers reviewing the 1N5948B datasheet, pinout, applications, or equivalent options, key selection criteria include its ±5% tolerance (B-suffix), 98 W surge rating at 1 ms, Pb-free DO-41 package, and guaranteed zener voltage stability under TL = 30°C lead temperature conditions.

Technical Context

The 1N5948B employs a silicon-oxide passivated junction for stable breakdown characteristics and low leakage. Its zener voltage is specified at IZT = 200 mA with thermal measurement controlled at 30°C lead temperature, 3/8″ from the case.

Zener impedance is derived from AC superposition (10% of IZT) and reflects dynamic regulation performance. The device exhibits a positive temperature coefficient above ~50 V, typical for high-voltage Zeners, and supports steady-state dissipation up to 3 W at TL = 75°C with derating above that temperature.

Key Specifications

Pinout & Package

Package: DO-41 (Case 59-10), axial-lead, void-free thermosetting plastic. Cathode indicated by band; anode is unmarked lead. Lead diameter not controlled within F dimension per JEDEC outline.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N5948A and BZX85C91, the 1N5948B delivers tighter voltage tolerance and higher surge resilience-critical for industrial power supplies and automotive clamping where regulation accuracy and transient robustness directly impact system safety and longevity.

Availability

1N5948B is available at Aetrix Electronics and suitable for switch-mode power supplies, industrial overvoltage protection circuits, and programmable voltage reference designs requiring stable component supply and long-term manufacturability.

Supply support for 1N5948B 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

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

The 1N59xxB series was designed for high-reliability voltage regulation in harsh-environment applications, emphasizing stable zener characteristics, high surge endurance, and extended temperature operation.

FAQ

What is the nominal zener voltage and tolerance of the 1N5948B?

The 1N5948B has a nominal zener voltage of 91 V with a tolerance of ±5%, as indicated by the "B" suffix. This means the actual measured zener voltage at IZT = 200 mA and TL = 30°C falls between 86.45 V and 95.55 V. This tight tolerance ensures predictable regulation behavior in feedback and protection circuits where voltage accuracy is critical. The 1N5948B's specification is guaranteed per ON Semiconductor's electrical characterization methodology.

How does the 1N5948B handle transient overvoltage events?

The 1N5948B supports a non-repetitive surge power rating of 98 W for 1 ms, enabling it to absorb transient energy without permanent degradation. This capability is validated under rectangular waveform conditions with TJ = 25°C prior to pulse. For sustained overvoltage, the device relies on its 3 W steady-state dissipation rating at TL = 75°C. Engineers must ensure thermal design accommodates both continuous and pulsed power to avoid exceeding junction temperature limits. The 1N5948B's surge rating is significantly higher than alternatives like BZX85C91.

What is the package type and lead configuration of the 1N5948B?

The 1N5948B uses the DO-41 package (JEDEC Case 59-10), an axial-lead, transfer-molded plastic housing with cathode polarity indicated by a band. Leads are corrosion-resistant and readily solderable, rated for 260°C for 10 seconds at 1/16″ from the case. The package dimensions are standardized: body length 4.10–5.20 mm, diameter 2.00–2.70 mm, lead diameter 0.71–0.86 mm. This compact form factor matches conventional 1 W packages while supporting 3 W operation. The 1N5948B's mechanical construction ensures compatibility with automated insertion and wave soldering.

What is the maximum reverse leakage current for the 1N5948B and at what voltage is it specified?

The 1N5948B specifies a maximum reverse leakage current of 0.25 μA at VR = 69.2 V, which is 76% of its nominal zener voltage. This ultra-low leakage minimizes quiescent current in high-impedance reference networks and improves accuracy in precision voltage monitoring applications. The value is measured under standard test conditions (TL = 30°C) and reflects the device's oxide-passivated junction quality. At lower voltages (e.g., 50 V), leakage drops further-typically below 0.1 μA-making the 1N5948B suitable for battery-powered or low-power sensing circuits.

Is the 1N5948B RoHS-compliant and what does the "G" suffix indicate?

Yes, the 1N5948B is RoHS-compliant. The "G" suffix in the ordering code (e.g., 1N5948B, G) explicitly denotes a Pb-free package, meeting EU Directive 2011/65/EU requirements. ON Semiconductor confirms this through material declarations and process validation. The device uses lead-free terminations and halogen-free molding compound. No exemptions apply-the 1N5948B contains no lead, mercury, cadmium, hexavalent chromium, PBB, or PBDE above threshold limits. This compliance applies to both tape-and-reel (1N5948BRL, G) and bulk box (1N5948B, G) variants.