Taiwan Semiconductor Corporation SRAS840HMNG

Overview

SRAS840HMNG from Taiwan Semiconductor is a single-die Schottky barrier rectifier in TO-263AB (D2PAK) package, rated for 40 V repetitive peak reverse voltage (V_RRM), 8 A average forward current (I_F), and 150 A non-repetitive surge current (I_FSM). It delivers low forward voltage drop of 0.55 V at 8 A and 25°C, enabling high-efficiency operation in compact DC/DC converters and AC/DC adapters.

For engineers reviewing the SRAS840HMNG datasheet, SRAS840HMNG pinout, SRAS840HMNG application, or SRAS840HMNG equivalent, key selection criteria include its 40 V V_RRM, 0.55 V V_F at 8 A, 3 °C/W junction-to-case thermal resistance, 125°C max junction temperature, and TO-263AB mechanical compatibility with high-power surface-mount layouts.

Technical Context

This device operates as a unidirectional power rectifier optimized for high-frequency switching topologies. Its guard ring structure provides overvoltage protection, while the matte tin-plated leads meet J-STD-002 solderability and JESD 201 Class 2 whisker resistance requirements.

The SRAS840HMNG exhibits 100 µA maximum reverse leakage (I_R) at 25°C and rated V_R, and maintains stable conduction up to 125°C junction temperature - critical for thermally constrained SMPS designs where thermal resistance (R_θJC = 3 °C/W) directly impacts power density.

Key Specifications

Pinout & Package

Package: TO-263AB (D2PAK) - Surface-mount power package with exposed metal tab (cathode-connected) for thermal and electrical grounding; 3-terminal configuration; RoHS-compliant, halogen-free molding compound (UL 94V-0).

Key Features

Applications

Equivalent & Alternatives

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

Compared with VS-8EWH04FN-M3/45 and SB840-E3/45, the SRAS840HMNG offers the lowest forward voltage in its class and optimal thermal performance for 8 A continuous duty - making it ideal for thermally aggressive, high-efficiency adapter and VRM applications where junction temperature margin is limited.

Availability

SRAS840HMNG is available at Aetrix Electronics and suitable for switching mode power supply (SMPS), USB-C power delivery adapters, and industrial DC/DC converter applications requiring stable component supply, consistent parametric performance, and long-term manufacturing continuity.

Supply support for SRAS840HMNG 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 power discrete manufacturer headquartered in Hsinchu, Taiwan, specializing in high-reliability rectifiers, TVS devices, and MOSFETs for industrial and computing markets.

The SRAS8xx series was developed to deliver high-current Schottky rectification with enhanced surge robustness and thermal efficiency in TO-263AB packaging - targeting cost-sensitive yet thermally demanding power conversion systems.

FAQ

What is the maximum junction temperature rating for SRAS840HMNG?

The SRAS840HMNG has a maximum junction temperature (T_J) rating of 125°C, as specified in the Absolute Maximum Ratings table. This limit applies under continuous operation and must be respected in thermal design - especially when operating near full 8 A current or in elevated ambient conditions. Derating curves in the datasheet confirm usable current drops to ~5.5 A at 100°C case temperature. The SRAS840HMNG must not exceed this 125°C threshold to ensure reliability and lifetime compliance.

Does SRAS840HMNG have a built-in guard ring, and what does it protect against?

Yes, the SRAS840HMNG incorporates a guard ring structure explicitly noted in its features list. This design element enhances edge termination robustness and protects against premature avalanche breakdown caused by localized electric field concentration during voltage transients. It improves ruggedness against line surges and switching spikes in SMPS circuits - reducing or eliminating the need for external snubber networks in many 40 V-class applications. The SRAS840HMNG's guard ring contributes directly to its 10,000 V/µs dv/dt rating.

Is SRAS840HMNG compatible with lead-free reflow soldering processes?

Yes, the SRAS840HMNG is fully compatible with lead-free reflow soldering. Its matte tin-plated leads meet J-STD-002 solderability requirements, and the device is rated for moisture sensitivity level 1 (per J-STD-020), meaning it can be stored indefinitely in dry packs and placed directly into standard Pb-free reflow profiles (peak ~260°C) without baking. The SRAS840HMNG's UL 94V-0 molding compound also withstands multiple thermal excursions without delamination or cracking.

What is the reverse leakage current specification for SRAS840HMNG at elevated temperature?

At 100°C junction temperature, the SRAS840HMNG specifies a maximum reverse leakage current (I_R) of 5 mA when biased at its rated 40 V reverse voltage. This value is confirmed in the Electrical Specifications table under "Reverse current @ rated V_R" for TJ = 100°C. At 25°C, leakage is limited to 100 µA max. Designers should account for this exponential increase in leakage when sizing output capacitors or calculating standby power in high-ambient applications using the SRAS840HMNG.

Can SRAS840HMNG be used as a direct replacement for SRAS830HMNG in an existing design?

No - the SRAS840HMNG is not a direct replacement for SRAS830HMNG due to differing V_RRM ratings: SRAS830HMNG is rated for 30 V, while SRAS840HMNG is rated for 40 V. Although both share identical I_F, I_FSM, package, and thermal specs, substituting SRAS840HMNG in a 30 V-design may introduce unnecessary cost and margin without functional benefit, while substituting SRAS830HMNG in a 40 V circuit risks reverse breakdown. Always verify system-level voltage stress before interchanging SRAS8xx variants.