Taiwan Semiconductor Corporation 1SMA5937

Overview

1SMA5937 from Taiwan Semiconductor is a surface-mount 33 V ±5% Zener diode in DO-214AC (SMA) package, rated for 1.5 W steady-state power dissipation, with 11.4 Ω dynamic impedance at 25.1 mA test current and typical leakage < 0.5 µA at 25.1 V reverse bias. It serves as a precision voltage reference or overvoltage clamp in DC/DC converters and SMPS feedback loops.

For engineers reviewing the 1SMA5937 datasheet, 1SMA5937 pinout, 1SMA5937 application, or 1SMA5937 equivalent, key selection criteria include its 33 V nominal Zener voltage, 1.5 W power rating, DO-214AC thermal performance on 5 mm × 5 mm Cu pad, low-inductance construction, and Class 3B HBM ESD rating - all critical for stable regulation in compact power designs.

Technical Context

The 1SMA5937 operates as a single-die, glass-passivated Zener diode optimized for stable voltage regulation under DC and pulsed conditions. Its junction temperature range spans −55°C to +150°C, and it maintains regulation within ±5% tolerance across thermal equilibrium conditions per JEDEC standards.

Designed for automated SMT placement, the device features matte tin-plated leads compliant with J-STD-002 solderability and meets JESD 201 Class 2 whisker resistance. Polarity is indicated by a cathode band, and moisture sensitivity is rated Level 1 per J-STD-020.

Key Specifications

Pinout & Package

DO-214AC (SMA) package: molded epoxy case with cathode band marking; matte tin-plated leads; weight ≈ 0.060 g; UL 94V-0 flammability rating.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MMBZ5252BS-7-F and BZX84-C33, the 1SMA5937 delivers 6× higher power handling and ~3× lower dynamic impedance - making it uniquely suitable for primary-side regulation and high-energy transient suppression where thermal robustness and regulation fidelity are mandatory.

Availability

1SMA5937 is available at Aetrix Electronics and suitable for switching mode power supplies, on-board DC/DC converters, and lighting applications requiring stable component supply, consistent parametric performance, and full traceability through J-STD-020-compliant packaging.

Supply support for 1SMA5937 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 1SMA59xx series was engineered specifically for high-reliability, surface-mount Zener regulation in compact power conversion systems - emphasizing thermal stability, low leakage, and automated assembly compatibility.

FAQ

What is the nominal Zener voltage of the 1SMA5937?

The 1SMA5937 has a nominal Zener voltage of 33 V with a guaranteed tolerance of ±5%, meaning its actual breakdown voltage falls between 31.35 V and 34.65 V when tested at 25.1 mA. This value is specified at thermal equilibrium per JEDEC standards and is validated across the full operating temperature range of −55°C to +150°C. The 1SMA5937 achieves this regulation using a glass-passivated silicon junction.

What is the maximum power dissipation rating for the 1SMA5937?

The 1SMA5937 is rated for 1.5 W DC power dissipation at lead temperature (T_L) = 75°C, with a linear derating of 20 mW/°C above that temperature. This rating assumes mounting on a 5 mm × 5 mm copper pad per the test condition defined in the datasheet. The 1SMA5937's DO-214AC package enables effective heat transfer to the PCB, supporting sustained operation in thermally demanding applications like SMPS feedback circuits.

Does the 1SMA5937 have an ESD rating, and if so, what is it?

Yes, the 1SMA5937 carries a JEDEC Class 3B Human Body Model (HBM) ESD rating, meaning it withstands ≥8 kV electrostatic discharge without functional degradation. This rating is achieved through process-level junction passivation and terminal design, and is verified per JESD22-A114. The 1SMA5937's ESD robustness supports reliable handling during automated SMT placement and post-assembly testing without additional protection circuitry.

What package type does the 1SMA5937 use, and what are its key mechanical attributes?

The 1SMA5937 uses the DO-214AC (SMA) surface-mount package: a molded epoxy case with UL 94V-0 flammability rating, matte tin-plated leads compliant with J-STD-002, and polarity indicated by a visible cathode band. Its weight is approximately 0.060 g, and it meets JESD 201 Class 2 whisker resistance. The 1SMA5937's footprint aligns with IPC-7351B standard land patterns for automated assembly.

How does the 1SMA5937 compare to lower-power Zener diodes like the BZX84-C33?

The 1SMA5937 differs from the BZX84-C33 primarily in power handling (1.5 W vs. 300 mW), dynamic impedance (11.4 Ω vs. 90 Ω), and thermal capability (same T_J max but superior derating due to DO-214AC thermal mass). While both regulate at 33 V, the 1SMA5937 sustains higher continuous current and rejects transients more effectively - making it appropriate for power-stage regulation where the BZX84-C33 would thermally saturate or exhibit excessive voltage drift.