Diodes Incorporated 1SMB5947B-13

Overview

1SMB5947B-13 from Diodes Incorporated is a 3.0W surface-mount power Zener diode with nominal zener voltage of 82 V (±5%), zener impedance of 2500 Ω at 4.6 mA test current, and maximum reverse leakage of 0.25 µA at 62.2 V. It operates across –65°C to +150°C and is used for precision voltage regulation in DC power supply rails and overvoltage protection circuits.

For engineers reviewing the 1SMB5947B-13 datasheet, 1SMB5947B-13 pinout, 1SMB5947B-13 application, or 1SMB5947B-13 equivalent, key selection criteria include zener voltage tolerance, thermal resistance (226 °C/W), power derating above +25°C, and ESD robustness (Class 3, >16 kV HBM).

Technical Context

This Zener diode functions as a shunt voltage reference and transient clamp, maintaining stable regulation under varying load and temperature conditions. Its 2500 Ω dynamic impedance at 4.6 mA and low 0.25 µA reverse leakage at VR = 62.2 V ensure tight voltage control in feedback loops and sensing paths.

The SMB package enables high-power dissipation (3.0 W at TL = +75°C) with low thermal resistance (25 °C/W junction-to-terminal), while its ±5% VZ tolerance and –65°C to +150°C operating range support industrial and automotive power rail stabilization.

Key Specifications

Pinout & Package

Package: SMB (Surface Mount Body), molded plastic case per UL 94V-0, polarity indicated by cathode band. Dimensions: 3.30–3.94 mm (A) × 4.06–4.57 mm (B) × 1.96–2.21 mm (C), weight ≈ 0.096 g.

Key Features

Applications

Availability

1SMB5947B-13 is available at Aetrix Electronics and suitable for industrial power supply regulation, automotive onboard charger clamping, and test equipment reference voltage applications requiring stable component supply and long-term lifecycle assurance.

Supply support for 1SMB5947B-13 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.

This device belongs to the SMB-series 3.0W Zener diode family, engineered for high-reliability voltage regulation and transient suppression in space-constrained, high-temperature industrial and automotive power systems.

FAQ

What is the maximum continuous power dissipation for 1SMB5947B-13 at +25°C ambient?

The device is rated for 550 mW at TA = +25°C, with linear derating of 4.4 mW/°C above that temperature. This limit assumes standard FR-4 PCB mounting per Diodes Inc. AP02001 pad layout. Exceeding this value without thermal relief risks junction overheating and parametric shift.

How does the 2500 Ω zener impedance affect regulation accuracy in a feedback loop?

At 4.6 mA test current, 2500 Ω impedance means a 1 mA change in zener current causes ~2.5 V deviation in output voltage. For high-accuracy references, this requires stable bias current and low-noise layout; it is appropriate for non-critical clamping but not sub-1% precision references.

Can 1SMB5947B-13 replace a 1N5375B in an existing design?

No - the 1N5375B is a 100 V, 5 W axial-leaded Zener. While both regulate, 1SMB5947B-13 has lower voltage (82 V), lower power (3.0 W), and SMB surface-mount packaging. Direct replacement would require PCB redesign, thermal validation, and verification of regulation stability at reduced power.

Is the cathode band orientation consistent across all SMB-packaged Zeners from Diodes Incorporated?

Yes - the cathode band is always located on the same end of the SMB body, aligned with the marking code (B947). Top-view schematic diagrams in DS32125 confirm cathode band position matches industry-standard SMB polarity convention used by ON Semiconductor, Vishay, and STMicroelectronics.