Taiwan Semiconductor Corporation S4B

Overview

S4B from Taiwan Semiconductor is a 4A, 100V surface-mount silicon rectifier diode in DO-214AB (SMC) package, featuring glass-passivated junction, low forward voltage drop (≤1.15 V at 4 A), and high surge capability (100 A IFSM). It serves as a primary AC/DC conversion element in compact power adapters and offline SMPS.

For engineers reviewing the S4B datasheet, S4B pinout, S4B application, or S4B equivalent, key selection criteria include its 100 V repetitive peak reverse voltage, 1500 ns reverse recovery time, junction-to-lead thermal resistance of 13 °C/W, and RoHS/halogen-free compliance for industrial and consumer power designs.

Technical Context

The S4B is a single-die, standard-recovery silicon rectifier optimized for cost-sensitive, medium-voltage switching power supplies. Its 1500 ns trr and 60 pF junction capacitance reflect trade-offs favoring ruggedness and surge tolerance over ultra-fast switching.

Thermal performance is defined by R_θJL = 13 °C/W and R_θJA = 47 °C/W under standard mounting conditions. The device operates across –55 °C to +150 °C junction temperature range with moisture sensitivity level 1 per J-STD-020.

Key Specifications

Pinout & Package

Package: DO-214AB (SMC), surface-mount, cathode-indicated by band, matte tin-plated leads, UL 94V-0 molding compound, 0.210 g typical weight.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MUR4100 and VS-4EWH01-M3/54, the S4B delivers balanced performance-moderate t_rr and competitive V_F-making it optimal for 50–120 kHz industrial and adapter designs where cost, ruggedness, and thermal stability are prioritized over ultrafast switching.

Availability

S4B is available at Aetrix Electronics and suitable for AC/DC adapters, LED lighting drivers, and industrial SMPS requiring stable component supply, consistent parametric performance, and full RoHS/halogen-free compliance.

Supply support for S4B 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, including rectifiers, TVS diodes, MOSFETs, and IGBTs, with global distribution and AEC-Q200 qualified lines.

The S4A–S4M series was designed specifically for cost-effective, high-reliability AC/DC front-end rectification in consumer, industrial, and lighting power supplies-emphasizing surge robustness, manufacturability, and environmental compliance.

FAQ

What is the maximum repetitive peak reverse voltage (V_RRM) for the S4B?

The S4B has a V_RRM of 100 V, as confirmed in the Absolute Maximum Ratings table of the Taiwan Semiconductor K2102 datasheet. This value defines the highest reverse voltage the S4B can block repeatedly without breakdown and is critical for selecting appropriate safety margins in 24 V or 48 V input systems. The S4B is part of the S4A–S4M family, where marking code "S4B" explicitly corresponds to the 100 V variant.

Does the S4B support lead-free reflow soldering?

Yes, the S4B features matte tin-plated leads compliant with J-STD-002 for solderability and is rated moisture sensitivity level 1 per J-STD-020, meaning it can be processed using standard lead-free reflow profiles (e.g., JEDEC J-STD-020D) without pre-baking. The DO-214AB package and halogen-free molding compound further ensure compatibility with modern eco-conscious manufacturing. This applies specifically to the S4B, not inferred from other family members.

What is the reverse recovery time (t_rr) of the S4B, and how does it affect circuit performance?

The S4B has a reverse recovery time of 1500 ns under IF = 0.5 A, IR = 1.0 A, and Irr = 0.25 A test conditions. This standard-recovery characteristic introduces measurable switching loss and potential ringing in high-frequency SMPS (>150 kHz), but provides superior surge robustness and lower forward voltage versus ultrafast alternatives. Designers should verify EMI filter sizing and snubber requirements when using the S4B in 50–120 kHz applications.

Is the S4B suitable for automotive applications?

No-the S4B is not AEC-Q101 qualified, and Taiwan Semiconductor explicitly states that the S4A–S4M series is not designed for medical, life-saving, or life-sustaining applications. While its –55 °C to +150 °C junction range meets some automotive ambient requirements, lack of qualification, stress testing, and traceability documentation excludes the S4B from automotive power systems. For such use cases, qualified alternatives like the ON Semi MUR4100G or Vishay VSKY4100 must be selected instead of the S4B.

How does the thermal resistance of the S4B impact PCB layout?

The S4B's junction-to-lead thermal resistance (R_θJL) is 13 °C/W, meaning effective heat transfer relies on direct copper connection from the cathode/anode pads to internal or external copper planes. To maintain T_J ≤ 125 °C at 4 A, designers should allocate ≥ 100 mm² of 2 oz copper per terminal, avoid narrow traces, and ensure no thermal isolation under the DO-214AB body. This thermal behavior is measured and specified for the S4B itself-not estimated from adjacent variants.