Diodes Incorporated 1SMB5917B-13

Overview

1SMB5917B-13 from Diodes Incorporated is a 3.0W surface-mount power Zener diode with a nominal zener voltage of 4.7V (±5%), 5mA test current, 79.8Ω dynamic impedance at test current, and 1.5µA maximum reverse leakage at 1.5V. It serves as a precision voltage reference or overvoltage clamp in DC power rails and regulator feedback networks.

For engineers reviewing the 1SMB5917B-13 datasheet, 1SMB5917B-13 pinout, 1SMB5917B-13 application, or 1SMB5917B-13 equivalent, key selection criteria include zener voltage tolerance, thermal resistance (226°C/W), power derating above +25°C, and SMB package compatibility with automated SMT assembly.

Technical Context

This Zener diode operates in reverse breakdown to maintain stable voltage regulation under varying load and temperature conditions. Its 4.7V nominal zener voltage falls within the low-voltage range optimized for 5V system rail clamping and feedback sensing, with a negative temperature coefficient typical of sub-5V Zeners.

The device uses a planar silicon junction structure encapsulated in an SMB molded plastic case rated UL 94V-0. Thermal performance is defined for FR-4 PCB mounting per AP02001 layout, with junction-to-ambient thermal resistance of 226°C/W and junction-to-terminal resistance of 25°C/W.

Key Specifications

Pinout & Package

Package: SMB (Surface Mount B), molded plastic case with cathode band marking; dimensions: 4.06–4.57mm length × 3.30–3.94mm width × 1.96–2.21mm height; weight ≈ 0.096g; polarity indicated by cathode band.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX84-C4V7 and 1N5333B, the 1SMB5917B-13 delivers optimal balance of SMT manufacturability, 3.0W clamping headroom, and SMB footprint-making it ideal for modern 5V DC/DC converter protection and feedback circuits where thermal management and automation compatibility are critical.

Availability

1SMB5917B-13 is available at Aetrix Electronics and suitable for 5V power rail clamping, switching regulator feedback reference, and USB port overvoltage protection requiring stable component supply and consistent parametric performance across production lots.

Supply support for 1SMB5917B-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 and manufacturing operations across Asia and the Americas.

The 1SMB59xxB series belongs to Diodes' high-power Zener diode product line, engineered specifically for reliable voltage regulation and transient suppression in compact SMT power supply designs targeting consumer, computing, and industrial markets.

FAQ

What is the maximum continuous power dissipation for 1SMB5917B-13 at +25°C ambient?

The maximum continuous power dissipation is 550mW at +25°C ambient temperature, derating linearly at 4.4mW/°C above that point. This value assumes standard FR-4 PCB mounting per Diodes' AP02001 pad layout. Exceeding this limit without thermal enhancement risks junction temperature exceeding 150°C, potentially causing parameter shift or failure.

How does the 4.7V zener voltage relate to its use in 5V systems?

The 4.7V nominal zener voltage provides a safety margin below the 5.5V absolute maximum rating of most 5V logic devices. When used as a shunt clamp, it begins conducting significantly near 4.7V, limiting rail excursions to ≤5.0V under transient conditions-protecting downstream components while avoiding false triggering during normal 5V operation.

Is 1SMB5917B-13 compatible with lead-free reflow profiles?

Yes, the device features matte tin-plated copper alloy leadframe and is qualified for lead-free reflow soldering per JEDEC J-STD-020. Its moisture sensitivity level is Class 1, meaning it can be stored indefinitely at ≤30°C/60% RH without baking prior to assembly, supporting standard SMT production flow.

What is the significance of the "B" suffix in 1SMB5917B-13?

Per Diodes Incorporated's ordering nomenclature, the "B" denotes ±5% zener voltage tolerance. The "-13" suffix indicates 3,000-piece tape-and-reel packaging. This distinguishes it from tighter-tolerance variants (e.g., "A" = ±2%) and alternate packaging formats like bulk or ammo pack.