Taiwan Semiconductor Corporation 1SMB5934

Overview

1SMB5934 from Taiwan Semiconductor is a surface-mount 24 V Zener diode rated for 3 W continuous power dissipation, with 5% voltage tolerance (22.8–25.2 V), 15.6 Ω dynamic impedance at 19 mA test current, and DO-214AA (SMB) package. It regulates voltage in DC/DC converters and provides overvoltage protection in lighting drivers and SMPS secondary-side feedback loops.

For engineers reviewing the 1SMB5934 datasheet, 1SMB5934 pinout, 1SMB5934 application, or 1SMB5934 equivalent, key selection criteria include its 24 V nominal Zener voltage, 19 mA test current, 15.6 Ω Zener impedance, 150 °C max junction temperature, and SMB package thermal performance (R_θJA = 226 °C/W).

Technical Context

The 1SMB5934 operates as a single-die, glass-passivated Zener diode optimized for stable voltage reference and transient clamping in medium-power DC circuits. Its 24 V nominal breakdown voltage is specified at 19 mA (I_ZT) with ±5% tolerance and exhibits low dynamic impedance (15.6 Ω) under regulated conduction.

Thermal design relies on its DO-214AA package with R_θJL = 25 °C/W to lead and R_θJA = 226 °C/W to ambient (on standard PCB). Maximum DC Zener current is 63 mA, and leakage current remains ≤1 μA at 18.2 V reverse bias.

Key Specifications

Pinout & Package

DO-214AA (SMB) surface-mount package with cathode indicated by a band; matte tin-plated leads, moisture sensitivity level 1 per J-STD-020.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N5934B and 1N5934A, the 1SMB5934 delivers superior thermal performance in SMT form factor, enabling higher reliability in compact, high-density power supplies without sacrificing voltage accuracy or surge robustness.

Availability

1SMB5934 is available at Aetrix Electronics and suitable for switching mode power supplies, on-board DC/DC converters, and LED lighting drivers requiring stable component supply, consistent Zener voltage matching, and RoHS-compliant surface-mount packaging.

Supply support for 1SMB5934 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

Taiwan Semiconductor Corporation (TSC) is a vertically integrated semiconductor manufacturer specializing in discrete power devices, analog ICs, and protection components for industrial and consumer markets.

The 1SMB59xx series was developed to deliver high-reliability, surface-mount Zener diodes with tight voltage tolerance, low impedance, and robust thermal performance for next-generation compact power conversion systems.

FAQ

What is the nominal Zener voltage and tolerance of the 1SMB5934?

The 1SMB5934 has a nominal Zener voltage of 24 V with a tolerance of ±5%, meaning its actual breakdown voltage falls between 22.8 V and 25.2 V when measured at the specified 19 mA test current (I_ZT). This tolerance is confirmed in the Electrical Specifications table of the official Taiwan Semiconductor datasheet (Version M2102), and applies strictly under thermal equilibrium at 25 °C ambient.

What is the maximum continuous power dissipation for the 1SMB5934?

The 1SMB5934 is rated for 3 W continuous power dissipation at a lead temperature (T_L) of 75 °C, with a linear derating of 40 mW/°C above that temperature. At 25 °C ambient on a standard PCB, its DC power dissipation limit is 550 mW, reflecting its thermal resistance to ambient (R_θJA = 226 °C/W). These values are defined in the Absolute Maximum Ratings section of the Taiwan Semiconductor datasheet.

Does the 1SMB5934 have RoHS and halogen-free compliance?

Yes, the 1SMB5934 is RoHS compliant and halogen-free per IEC 61249-2-21, as explicitly stated in the FEATURES section of the Taiwan Semiconductor datasheet (Version M2102). The device uses matte tin-plated leads and UL 94V-0 compliant molding compound, meeting both environmental and safety standards for global electronics manufacturing.

What package type does the 1SMB5934 use, and what are its mechanical identifiers?

The 1SMB5934 uses the DO-214AA (SMB) surface-mount package, identified by its rectangular body, gull-wing leads, and cathode band marking. Mechanical data confirm it weighs approximately 0.100 g, meets JESD 201 Class 2 whisker resistance, and has moisture sensitivity level 1 per J-STD-020-making it compatible with standard reflow profiles without baking.

How does the 1SMB5934 perform thermally in a typical PCB layout?

In a standard FR-4 PCB layout with zero lead length, the 1SMB5934 exhibits a junction-to-ambient thermal resistance (R_θJA) of 226 °C/W and a junction-to-lead resistance (R_θJL) of 25 °C/W. This means at 3 W dissipation, junction temperature rise above ambient reaches ~677 °C-so practical operation requires copper pad heatsinking (e.g., 5 mm × 5 mm Cu pad per datasheet Note 1) to stay within the 150 °C T_JMAX limit.