Taiwan Semiconductor Corporation S2DFS

Overview

S2DFS from Taiwan Semiconductor is a 2 A, 200 V standard surface-mount silicon rectifier diode in SOD-128 package, featuring glass-passivated junction, 50 A surge rating (8.3 ms), 0.98 V max forward voltage at 2 A/25°C, and 1 µA max reverse leakage at 25°C. It serves as primary AC/DC input rectifier in compact DC-DC converters.

For engineers reviewing the S2DFS datasheet, S2DFS pinout, S2DFS application, or S2DFS equivalent, key selection criteria include repetitive peak reverse voltage (200 V), thermal resistance (R_θJL = 14 °C/W), moisture sensitivity level (MSL 1), RoHS/halogen-free compliance, and SOD-128 footprint compatibility with automated placement.

Technical Context

The S2DFS operates as a single-die, unidirectional standard recovery rectifier optimized for switching-mode power supplies. Its glass-passivated junction ensures stable reverse characteristics across -55°C to +150°C junction temperature range, with 14 °C/W junction-to-lead thermal resistance enabling efficient heat transfer to PCB copper pads.

Electrical behavior is defined by forward voltage ≤0.98 V at 2 A/25°C and ≤0.98 V at 2 A/125°C, reverse current ≤1 µA at 25°C and ≤33 µA at 125°C, and junction capacitance of 12 pF at 1 MHz/4 V - supporting high-frequency rectification without excessive switching loss.

Key Specifications

Pinout & Package

Package: SOD-128 - surface-mount, molded plastic case with matte tin-plated leads, UL 94V-0 rated, polarity indicated by cathode band, weight 0.027 g.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MUR220 and VS-2EY20, the S2DFS delivers optimal balance of low forward voltage, zero moisture sensitivity handling, and cost efficiency for standard-recovery applications below 60 kHz - especially where thermal management relies on PCB copper rather than external heatsinking.

Availability

S2DFS is available at Aetrix Electronics and suitable for DC-DC converters, switching mode inverters, and general-purpose power rectification requiring stable component supply, consistent MSL Level 1 handling, and SOD-128 footprint reliability.

Supply support for S2DFS 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 analog and discrete semiconductor manufacturer headquartered in Hsinchu, Taiwan, specializing in power devices, rectifiers, TVS diodes, and MOSFETs for industrial and consumer markets.

The S2DFS belongs to TSC's S2xFS standard rectifier family, designed specifically for cost-effective, high-yield surface-mount rectification in space-constrained AC/DC and DC/DC power stages where reliability under thermal stress and humidity is essential.

FAQ

What is the maximum junction temperature rating for the S2DFS?

The S2DFS has a maximum junction temperature (T_J) of +150°C, with operational capability down to -55°C. This rating is validated under specified thermal conditions using a 5 mm × 5 mm copper pad test board, and enables use in industrial environments without active cooling. The S2DFS maintains electrical integrity within this full range, including stable reverse leakage and forward voltage performance.

Does the S2DFS have a specified reverse recovery time (t_rr)?

No, the S2DFS datasheet does not specify reverse recovery time (t_rr) because it is a standard recovery rectifier, not an ultrafast or fast recovery type. Its internal construction prioritizes low forward voltage and robust surge capability over speed; typical t_rr is in the microsecond range. For applications requiring sub-100 ns recovery, consider alternatives like the MUR220 - but the S2DFS remains appropriate for ≤60 kHz switching frequencies where recovery loss is negligible.

What does the marking code 'S2DFS' indicate on the device body?

The marking code 'S2DFS' printed on the S2DFS device body directly identifies the 200 V variant within the S2xFS family. Per TSC documentation, the 'D' in S2DFS corresponds to 200 V V_RRM; other variants include S2GFS (400 V), S2JFS (600 V), etc. This marking is used for visual inspection and automated optical recognition during assembly, and matches the ordering code exactly - no decoding or translation is required.

Can the S2DFS be used in place of a Schottky diode in a 24 V input DC-DC converter?

The S2DFS is not a drop-in replacement for Schottky diodes due to its higher forward voltage (0.98 V vs. typical 0.4–0.6 V for Schottky) and standard recovery behavior. In a 24 V input DC-DC converter, using S2DFS would increase conduction loss and potentially cause EMI from slow turn-off. However, the S2DFS is viable where cost, surge robustness (50 A IFSM), or elevated temperature operation (>125°C) outweigh efficiency concerns - but system-level validation of thermal and efficiency impact is required before substituting S2DFS for Schottky.

What is the recommended PCB pad layout for the S2DFS in SOD-128 package?

TSC specifies a suggested pad layout for the S2DFS in the SOD-128 package that uses 5 mm × 5 mm copper pads per terminal to achieve the published R_θJA = 74 °C/W and R_θJL = 14 °C/W values. The layout must maintain the cathode band orientation, provide ≥0.2 mm solder mask dam between pads, and follow IPC-7351B SOD-128 land pattern dimensions. Deviation from this layout will degrade thermal performance and may exceed junction temperature limits at full 2 A load.