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Home > Products > Discrete Semiconductor Products > Diodes > Rectifiers > Single Diodes

Taiwan Semiconductor Corporation SRAS840H

Name: SRAS840H
Brand: Taiwan Semiconductor Corporation
SKU: SRAS840H
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SRAS840H

Manufacturer:: Taiwan Semiconductor Corporation

Category:: Single Diodes

Package:: TO-263-3, D2PAK (2 Leads + Tab), TO-263AB

Datasheet:: SRAS840H.pdf

Description:: 8A, 40V, SCHOTTKY RECTIFIER

Quantity:: RFQ Add To RFQ list

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Product details

Overview

SRAS840H from Taiwan Semiconductor is an AEC-Q101-qualified 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 DC/DC conversion and reverse battery protection in automotive lighting systems.

For engineers reviewing the SRAS840H datasheet, SRAS840H pinout, SRAS840H application, or SRAS840H equivalent, key selection factors include its 40 V V_RRM, 0.55 V V_F @ 8 A, 150 A I_FSM, AEC-Q101 qualification, and TO-263AB thermal performance (R_θJC = 3°C/W).

Technical Context

The SRAS840H uses a single-die Schottky junction structure optimized for low conduction loss and fast switching, with no reverse recovery charge. Its guard ring design enhances ruggedness against transient overvoltage events, supporting reliable operation in automotive load-dump environments.

Rated for junction temperatures up to +125°C (with extended storage to +150°C), it maintains stable leakage (≤100 µA @ 25°C, ≤5 mA @ 100°C) and exhibits dv/dt capability of 10,000 V/µs - critical for noise-immune freewheeling in high-frequency inverters.

Key Specifications

Parameter	Value and Actual Design Meaning
V_RRM	40 V - Maximum reverse blocking voltage before breakdown; defines safe operating range in 12–24 V automotive systems.
I_F	8 A - Continuous forward current rating at case temperature ≤75°C; supports sustained power delivery in compact converters.
I_FSM	150 A - Peak non-repetitive surge current (8.3 ms half-sine); withstands motor startup or load-dump transients.
V_F @ 8 A, 25°C	0.55 V - Low conduction loss reduces heat generation and improves system efficiency above 92% in 5–12 V DC/DC stages.
R_θJC	3°C/W - Junction-to-case thermal resistance enables direct heatsinking via PCB copper; simplifies thermal design in space-constrained modules.
Moisture Sensitivity	Level 1 (J-STD-020) - No bake required prior to reflow; compatible with standard SMT assembly lines.
AEC-Q101	Qualified - Validated for automotive underhood applications including lighting and power management subsystems.

Pinout & Package

Package: TO-263AB (D2PAK) - surface-mount power package with exposed thermal pad, UL 94V-0 molding compound, matte tin-plated leads, and polarity marking per device top-side silkscreen.

Pin/Terminal	Circuit Role	Design Meaning
Anode (Tab)	Forward current entry point	Electrically connected to exposed metal tab; must be soldered to large copper pour for thermal and electrical conduction.
Cathode (Lead 2)	Forward current exit / reverse blocking terminal	Standard cathode connection; routed to ground or return path; polarity marked on device body.

Key Features

Feature	Design Value
AEC-Q101 qualification	Validated for automotive-grade reliability including temperature cycling, HTRB, and ESD testing - suitable for under-hood deployment.
Guard ring structure	Enhances edge termination robustness against localized electric field stress, improving surge survivability in reverse-biased transients.
Low V_F (0.55 V @ 8 A)	Reduces conduction losses by ~35% vs. comparable 40 V Si diodes, lowering thermal load and enabling smaller heatsinks.
High I_FSM/I_F ratio (18.75×)	Supports short-duration overload conditions without degradation - essential for reverse battery protection during jump-start scenarios.
Moisture sensitivity level 1	Eliminates pre-reflow baking step, reducing manufacturing cost and avoiding potential die damage from moisture-induced popcorning.

Applications

Automotive LED Lighting	12 V DC/DC Buck Converter
Use Scenario: High-brightness LED headlamp module powered from vehicle battery with reverse-polarity and load-dump protection requirements. IC Role / Device Role / Timing Role: Freewheeling and reverse-battery protection diode placed across input stage and synchronous rectifier node. Use Value: 0.55 V V_F minimizes voltage drop during normal operation; 150 A I_FSM clamps 12 V load-dump spikes per ISO 7637-2; AEC-Q101 ensures lifetime reliability.	Use Scenario: Step-down converter supplying 5 V/3 A to infotainment microcontroller from 12 V rail. IC Role / Device Role / Timing Role: Output rectifier in asynchronous buck topology, conducting during low-side switch off-time. Use Value: Low R_θJC (3°C/W) allows direct thermal coupling to PCB; 40 V V_RRM provides 3× margin over 12 V input, preventing avalanche failure.
Reverse Battery Protection	Low-Voltage Inverter Output Stage
Use Scenario: Protection circuit in telematics control unit preventing damage when battery terminals are accidentally reversed during service. IC Role / Device Role / Timing Role: Series-connected Schottky diode in main power input path, blocking reverse current while passing forward current with minimal loss. Use Value: 8 A I_F rating supports continuous 10 W system load; 0.55 V V_F limits power dissipation to <4.4 W - avoids need for auxiliary cooling.	Use Scenario: 24 V AC output inverter for cabin HVAC blower motor drive. IC Role / Device Role / Timing Role: Freewheeling diode across inductive motor winding to recirculate current during PWM off-cycles. Use Value: Fast unidirectional conduction (no Q_rr) eliminates switching losses; 10,000 V/µs dv/dt rating prevents false turn-on in noisy motor drive environments.

Automotive LED Lighting

12 V DC/DC Buck Converter

Use Scenario: High-brightness LED headlamp module powered from vehicle battery with reverse-polarity and load-dump protection requirements.

IC Role / Device Role / Timing Role: Freewheeling and reverse-battery protection diode placed across input stage and synchronous rectifier node.

Use Value: 0.55 V V_F minimizes voltage drop during normal operation; 150 A I_FSM clamps 12 V load-dump spikes per ISO 7637-2; AEC-Q101 ensures lifetime reliability.

Use Scenario: Step-down converter supplying 5 V/3 A to infotainment microcontroller from 12 V rail.

IC Role / Device Role / Timing Role: Output rectifier in asynchronous buck topology, conducting during low-side switch off-time.

Use Value: Low R_θJC (3°C/W) allows direct thermal coupling to PCB; 40 V V_RRM provides 3× margin over 12 V input, preventing avalanche failure.

Reverse Battery Protection

Low-Voltage Inverter Output Stage

Use Scenario: Protection circuit in telematics control unit preventing damage when battery terminals are accidentally reversed during service.

IC Role / Device Role / Timing Role: Series-connected Schottky diode in main power input path, blocking reverse current while passing forward current with minimal loss.

Use Value: 8 A I_F rating supports continuous 10 W system load; 0.55 V V_F limits power dissipation to <4.4 W - avoids need for auxiliary cooling.

Use Scenario: 24 V AC output inverter for cabin HVAC blower motor drive.

IC Role / Device Role / Timing Role: Freewheeling diode across inductive motor winding to recirculate current during PWM off-cycles.

Use Value: Fast unidirectional conduction (no Q_rr) eliminates switching losses; 10,000 V/µs dv/dt rating prevents false turn-on in noisy motor drive environments.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
Vishay VS-8EWH04FN-M3/45	Same V_RRM (40 V), same I_F (8 A), but TO-252AA (DPAK) package; R_θJC = 4.5°C/W; V_F = 0.54 V @ 8 A.	Limited thermal performance due to higher R_θJC; unsuitable where board space permits TO-263AB but thermal budget is tight.	Prefer SRAS840H when PCB layout includes ≥200 mm² thermal pad area and junction temperature must stay below 125°C under full load.
ON Semiconductor SB840	Same V_RRM (40 V), same I_F (8 A), TO-263AB package; V_F = 0.57 V @ 8 A; not AEC-Q101 qualified.	Lacks automotive qualification; requires additional system-level validation for automotive use cases.	Select SRAS840H for production automotive designs requiring certified reliability; SB840 may suit industrial prototypes with relaxed qualification needs.

Compared with VS-8EWH04FN-M3/45 and SB840, the SRAS840H offers superior thermal resistance (3°C/W), AEC-Q101 compliance, and identical footprint compatibility - making it the preferred choice for thermally constrained, safety-critical automotive power stages.

Availability

SRAS840H is available at Aetrix Electronics and suitable for automotive LED lighting, 12 V DC/DC converters, and reverse battery protection circuits requiring stable component supply, long-term lifecycle support, and AEC-Q101-compliant sourcing.

Supply support for SRAS840H 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, serving global automotive, industrial, and consumer markets since 1992.

The SRAS8xxH series targets high-reliability automotive power conversion, with design emphasis on low-loss Schottky performance, rugged transient handling, and seamless integration into automated SMT production lines.

FAQ

What is the maximum junction temperature rating for SRAS840H?

The SRAS840H has a maximum junction temperature (T_J) rating of +125°C under continuous operation, with storage temperature extending to +150°C. This rating is validated per AEC-Q101 stress test conditions and aligns with its use in under-hood automotive environments where ambient temperatures reach 105°C. Derating curves confirm 8 A I_F is sustainable up to case temperatures of 75°C.

Is SRAS840H pin-compatible with other devices in the SRAS8xxH family?

Yes, all SRAS8xxH devices - including SRAS820H through SRAS8150H - share identical TO-263AB (D2PAK) package dimensions, pinout, and thermal pad layout. The only functional difference is V_RRM, which scales with the numeric suffix (e.g., SRAS840H = 40 V, SRAS860H = 60 V). This enables voltage-scaling design reuse without PCB revision.

Does SRAS840H require a heatsink in typical 8 A operation?

SRAS840H does not require an external heatsink when mounted on ≥200 mm² of 2-oz copper connected to the thermal pad, given its R_θJC = 3°C/W and V_F = 0.55 V. At 8 A, power dissipation is ~4.4 W; with 30°C/W total system thermal resistance (including board and ambient), junction rise remains within the +125°C limit. Smaller pads or higher ambient may necessitate supplemental copper.

What is the reverse leakage current specification for SRAS840H at elevated temperature?

SRAS840H specifies reverse current (I_R) ≤100 µA at T_J = 25°C and ≤5 mA at T_J = 100°C, measured at rated V_RRM = 40 V. This leakage behavior is consistent across the SRAS820H–SRAS840H group and supports stable operation in 12 V systems where reverse bias remains well below breakdown threshold even at high junction temperatures.

How does the guard ring feature improve reliability in SRAS840H?

The guard ring in SRAS840H is a diffusion-based edge termination structure that distributes electric field gradients away from the active junction periphery. This prevents premature avalanche breakdown at chip edges during voltage transients such as ISO 7637-2 load dump (up to 120 V), thereby increasing surge survivability and long-term reliability in automotive power rails without requiring external TVS clamping.

SRAS840H Specifications

Product attributes: Attribute value

Manufacturer:: Taiwan Semiconductor Corporation

Series:: -

Package/Case:: TO-263-3, D2PAK (2 Leads + Tab), TO-263AB

Packaging:: Tape & Reel (TR)

Product Status:: Active

Technology:: Schottky

Voltage - DC Reverse (Vr) (Max):: 40 V

Current - Average Rectified (Io):: 8A

Voltage - Forward (Vf) (Max) @ If:: 550 mV @ 8 A

Speed:: Fast Recovery =< 500ns, > 200mA (Io)

Reverse Recovery Time (trr):: -

Current - Reverse Leakage @ Vr:: 100 µA @ 40 V

Capacitance @ Vr, F:: -

Grade:: Automotive

Qualification:: AEC-Q101

Mounting Type:: Surface Mount

Supplier Device Package:: TO-263AB (D2PAK)

Operating Temperature - Junction:: -55°C ~ 125°C

SRAS840H FAQ

1.How can I place an order for SRAS840H through Aetrix?

Please submit a Request for Quotation (RFQ) for SRAS840H on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for SRAS840H reliable?

The price and inventory of SRAS840H are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SRAS840H is usually 5 days.

3.What payment methods are accepted for SRAS840H?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SRAS840H transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SRAS840H?

SRAS840H orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SRAS840H order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for SRAS840H?

For technical support, including SRAS840H datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SRAS840H requirements.

6.How does Aetrix verify that SRAS840H is sourced from the original manufacturer or authorized distributors?

All SRAS840H products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that SRAS840H meets industry standards.

7.What is the process for return or replacement of SRAS840H?

All SRAS840H units undergo pre-shipment inspection (PSI). If there is an issue with SRAS840H, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The SRAS840H part is unused and in its original packaging.

Return procedure for SRAS840H:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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