onsemi S3AB

Overview

S3AB from Diodes Incorporated is a 3.0A, 50V peak repetitive reverse voltage glass passivated surface-mount rectifier in SMB package, featuring 1.15V forward voltage at 3.0A, 100A non-repetitive surge capability, and RoHS-compliant matte tin plating. It serves as a primary AC/DC input stage rectifier in compact power supplies for industrial control modules.

For engineers reviewing the S3AB datasheet, S3AB pinout, S3AB application, or S3AB equivalent, key selection criteria include its 10°C/W junction-to-terminal thermal resistance, 40pF typical capacitance at 1MHz, 10µA peak reverse current at 25°C, derated forward current curve up to +75°C, and SMB mechanical compatibility with automated pick-and-place assembly.

Technical Context

This device operates as a single-phase, half-wave silicon rectifier optimized for resistive or inductive loads at 60Hz. Its glass passivated die construction ensures stable reverse leakage performance across -65°C to +150°C operating range and enables reliable operation under transient surge conditions up to 100A (8.3ms half-sine).

The SMB package provides 0.093g mass and UL 94V-0 flammability rating, with cathode band polarity identification and solderable matte tin terminals meeting MIL-STD-202 Method 208. Thermal performance is defined with a 5.0mm² copper pad heat sink per JEDEC standards.

Key Specifications

Pinout & Package

Package: SMB (Surface-Mount Small Outline), molded plastic case with UL 94V-0 flammability rating, cathode identified by band marking, 0.093g mass.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MURS320T3G and VS-3A4FL-E3/5BT, S3AB offers optimal balance of low forward drop, compact SMB footprint, and cost-effective 50V-class rectification for general-purpose industrial AC-DC stages where speed and ultra-high VRRM are unnecessary.

Availability

S3AB is available at Aetrix Electronics and suitable for industrial AC-DC power supplies, LED driver input rectification, and embedded system auxiliary power requiring stable component supply and long-term manufacturing continuity.

Supply support for S3AB 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, marketing, and sales operations worldwide.

The S3x/B series belongs to Diodes' standard rectifier product line, engineered for cost-sensitive, high-volume AC/DC front-end applications demanding reliability, RoHS compliance, and automated assembly compatibility.

FAQ

What is the maximum allowable junction temperature for S3AB?

The S3AB has an operating junction temperature range of -65°C to +150°C per datasheet DS16005 Rev. 18-2. Its absolute maximum TJ is +150°C, but sustained operation above +125°C requires derating of forward current per Figure 1's derating curve and verification of thermal interface to the PCB copper pad.

Can S3AB be used in full-wave bridge configurations?

Yes, S3AB can be used as one leg in a discrete full-wave bridge rectifier. However, it is a single diode-not a pre-assembled bridge-so four units are required per bridge. Its 50V VRRM limits use to low-voltage AC inputs (e.g., ≤35V RMS), and matching VFM across all four devices is recommended for balanced current sharing.

Is S3AB suitable for high-frequency switching applications like SMPS output rectification?

No. S3AB is a standard recovery rectifier with typical reverse recovery time in the microsecond range (~2µs). It is not optimized for high-frequency switching; using it in >100kHz SMPS outputs would cause excessive switching losses and overheating. Fast or ultrafast recovery diodes (e.g., MUR, UF, or肖特基) are required instead.

How does the SMB package of S3AB compare thermally to the SMC version (S3A-13-F)?

S3AB in SMB has RθJT = 10°C/W, while the SMC-packaged S3A-13-F has RθJT = 7°C/W due to larger copper pad area and mass (0.21g vs. 0.093g). In identical PCB layouts, SMC delivers ~30% lower junction temperature rise at 3A, making it preferable for thermally demanding applications despite larger footprint.