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Taiwan Semiconductor Corporation TLD8S40AH
- Part No.:
- TLD8S40AH
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-218AB
- Datasheet:
-
TLD8S40AH.pdf
- Description:
- TVS DIODE 40VWM 64.5VC DO218AB
- Quantity:
- Payment:
- Shipping:
Inventory:9,583
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Product details
Overview
TLD8S40AH from Taiwan Semiconductor is a unidirectional transient voltage suppressor (TVS) diode in DO-218AB package, rated for 40 V working stand-off voltage (VWM), 44.4–49.1 V breakdown voltage (VBR), 64.5 V clamping voltage (VC) at 102 A peak impulse current, and 6600 W peak pulse power (10/1000 µs). It delivers automotive-grade surge protection for load dump events in 12 V/24 V vehicle electrical systems.
For engineers reviewing the TLD8S40AH datasheet, TLD8S40AH pinout, TLD8S40AH application, or TLD8S40AH equivalent, key selection criteria include its AEC-Q101 qualification, 175 °C junction capability, ISO 7637-2/16750-2 compliance, DO-218AB thermal performance (RθJC = 0.8 °C/W), and unidirectional polarity marking for correct PCB orientation.
Technical Context
The TLD8S40AH operates as a unidirectional avalanche diode with junction passivation optimized for high-reliability automotive environments. Its 175 °C maximum junction temperature and moisture sensitivity level 1 rating support under-hood deployment without derating concerns.
It meets ISO 7637-2 Pulse 5a/b (load dump) and ISO 16750-2 supply voltage variation tests, delivering 6600 W surge handling (10/1000 µs) and 5200 W (10/10000 µs), with clamping voltage tightly controlled at 64.5 V to protect downstream 40 V-rated electronics.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 40 V - Maximum continuous reverse operating voltage before conduction begins; sets system-level overvoltage trip threshold. |
| VBR (min/max) | 44.4 V / 49.1 V - Breakdown occurs within this range at 5 mA test current; defines precise avalanche onset for predictable clamping. |
| VC @ IPPM | 64.5 V at 102 A - Clamped voltage during 10/1000 µs surge; ensures protected ICs see ≤64.5 V under worst-case load dump. |
| PPPM (10/1000 µs) | 6600 W - Peak surge power handling capacity; supports robust protection against automotive load dump transients. |
| RθJC | 0.8 °C/W - Junction-to-case thermal resistance with ideal heatsink; enables high-power dissipation without exceeding 175 °C TJ. |
| TJ max | 175 °C - Maximum allowable junction temperature; certified for under-hood operation per AEC-Q101 stress testing. |
| IR @ VWM | 10 µA at 25 °C - Low leakage ensures minimal standby current draw in always-on vehicle modules. |
Pinout & Package
DO-218AB surface-mount package with cathode band marking; two-terminal device (anode and cathode) in axial leadframe configuration. Molding compound meets UL 94V-0; matte tin-plated leads compliant with J-STD-002 solderability.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current entry point during forward conduction | Connected to ground or low-side return path; enables unidirectional clamping from supply rail to GND. |
| Cathode | Current exit point during reverse avalanche | Marked with band; connected to protected supply rail (e.g., battery+); conducts surge current to ground when VIN exceeds VWM. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Passed stress tests including HTGB, HTRB, TCT, and UHAST - validated for automotive powertrain and chassis applications. |
| Junction passivation optimized design | Reduces surface leakage and enhances long-term reliability under high humidity and thermal cycling. |
| ISO 7637-2 & ISO 16750-2 compliant | Guarantees functional survival during standardized automotive load dump and supply interruption transients. |
| 175 °C junction capability | Enables direct mounting near heat sources (e.g., engine control units) without external thermal derating. |
| DO-218AB package with RθJC = 0.8 °C/W | Supports high-power transient dissipation with minimal thermal interface requirements - no dedicated heatsink needed for typical 10 ms load dump pulses. |
Applications
| Engine Control Unit (ECU) Power Input Protection | Body Control Module (BCM) Battery Rail Protection |
|---|---|
Use Scenario: Protects microcontroller, CAN transceivers, and analog sensors in ECUs exposed to alternator load dump surges up to ±120 V. IC Role / Device Role / Timing Role: Unidirectional TVS placed between battery+ and GND, clamping transients before they reach LDOs and MCU power pins. Use Value: Limits voltage seen by downstream 40 V-rated regulators to ≤64.5 V, preventing latch-up or oxide breakdown during 6600 W surge events. | Use Scenario: Secures BCM power input against jump-start spikes, load dump, and inductive switching noise in 12 V/24 V dual-battery architectures. IC Role / Device Role / Timing Role: Primary surge suppression element on main 12 V supply rail, coordinated with upstream fuses and downstream LC filters. Use Value: Maintains system uptime by absorbing 10/1000 µs transients without degradation, verified across -40 °C to +125 °C ambient. |
| Advanced Driver Assistance Systems (ADAS) Camera Power Supply | Electric Power Steering (EPS) Motor Driver Protection |
Use Scenario: Shields image sensor and serializer ICs in rear-view and surround-view cameras from battery line disturbances during ignition and accessory mode transitions. IC Role / Device Role / Timing Role: Fast-response unidirectional clamp on 12 V camera module input, placed immediately after connector to minimize inductance. Use Value: Achieves <1 ns response time and 64.5 V clamping to preserve signal integrity of MIPI CSI-2 links and prevent pixel corruption. | Use Scenario: Safeguards gate drivers and current-sense amplifiers in EPS motor control units subjected to high-current inductive kickback during steering actuation. IC Role / Device Role / Timing Role: High-energy TVS on H-bridge DC bus rail, parallel to bulk capacitance and upstream of MOSFET half-bridges. Use Value: Handles repetitive 10/10000 µs surges up to 5200 W while maintaining stable VC, preventing false overvoltage shutdowns during dynamic torque delivery. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ40A | Lower PPPM (400 W vs. 6600 W); SMA package (RθJC ≈ 45 °C/W); VC = 64.5 V same, but lower IPPM (64.3 A). | Not suitable for load dump; limited to ESD and low-energy transients in non-automotive consumer systems. | Select TLD8S40AH for automotive load dump; SMAJ40A only for board-level ESD where power is <500 W. |
| SMCJ40A | Same DO-214AB package; PPPM = 1500 W (10/1000 µs); VC = 64.5 V; RθJC ≈ 2.5 °C/W - significantly higher thermal resistance than TLD8S40AH's 0.8 °C/W. | Acceptable for mild load dump in 12 V systems with heatsinking, but fails repeated 6600 W pulses without thermal runaway. | TLD8S40AH provides 4.4× higher surge power and 3× better thermal performance - critical for AEC-Q101-compliant EPS or ADAS designs. |
Compared with SMAJ40A and SMCJ40A, the TLD8S40AH delivers 4.4× higher peak power handling, 3× lower junction-to-case thermal resistance, and full AEC-Q101 qualification - making it the only viable choice for automotive load dump protection where sustained 6600 W surges and 175 °C operation are mandatory.
Availability
TLD8S40AH is available at Aetrix Electronics and suitable for automotive engine control units, body control modules, ADAS camera power supplies, and electric power steering systems requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for TLD8S40AH 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 Company (TSC) is a vertically integrated semiconductor manufacturer specializing in discrete power devices, TVS diodes, and automotive-qualified components since 1979.
The TLD8S series was designed specifically for high-energy automotive transient suppression, targeting ISO 7637-2 load dump and ISO 16750-2 supply surge immunity in engine, chassis, and safety-critical ECUs.
FAQ
Is TLD8S40AH unidirectional or bidirectional?
TLD8S40AH is a unidirectional TVS diode, indicated by the "H" suffix (vs. "CAH" for bidirectional variants). It conducts only in reverse bias above VBR, with cathode marked for correct orientation toward the protected supply rail. This makes it ideal for clamping positive transients on battery-fed rails to ground.
What is the clamping voltage of TLD8S40AH at rated surge current?
The TLD8S40AH has a maximum clamping voltage (VC) of 64.5 V at 102 A peak impulse current (10/1000 µs waveform). This value is guaranteed across temperature and ensures protected downstream ICs remain below their absolute maximum ratings during automotive load dump events.
Does TLD8S40AH meet AEC-Q101 reliability standards?
Yes, TLD8S40AH is fully AEC-Q101 qualified, having passed high-temperature reverse bias (HTRB), high-temperature gate bias (HTGB), temperature cycling (TCT), and unbiased highly accelerated stress test (UHAST). This certification confirms suitability for automotive powertrain and safety-related applications.
What package does TLD8S40AH use, and what are its thermal characteristics?
TLD8S40AH uses the DO-218AB surface-mount package with RθJC = 0.8 °C/W (with ideal heatsink). Its low thermal resistance enables efficient dissipation of 6600 W surges without exceeding 175 °C junction temperature, eliminating need for external heatsinks in most automotive PCB layouts.
How does TLD8S40AH compare to standard SMCJ40A in surge capability?
TLD8S40AH delivers 6600 W peak pulse power (10/1000 µs), over 4× higher than SMCJ40A's 1500 W rating. Its RθJC of 0.8 °C/W also outperforms SMCJ40A's ~2.5 °C/W, enabling reliable operation under repeated high-energy transients where SMCJ40A would thermally saturate.
TLD8S40AH Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Taiwan Semiconductor Corporation
- Package/Case:
- DO-218AB
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 40V
- Voltage - Breakdown (Min):
- 44.4V
- Voltage - Clamping (Max) @ Ipp:
- 64.5V
- Current - Peak Pulse (10/1000µs):
- 102A
- Power - Peak Pulse:
- 6600W (6.6kW)
- Power Line Protection:
- No
- Applications:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 175°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-218AB
TLD8S40AH FAQ
1.How can I place an order for TLD8S40AH through Aetrix?
Please submit a Request for Quotation (RFQ) for TLD8S40AH 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 TLD8S40AH reliable?
The price and inventory of TLD8S40AH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TLD8S40AH is usually 5 days.
3.What payment methods are accepted for TLD8S40AH?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TLD8S40AH transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TLD8S40AH?
TLD8S40AH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TLD8S40AH 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 TLD8S40AH?
For technical support, including TLD8S40AH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TLD8S40AH requirements.
6.How does Aetrix verify that TLD8S40AH is sourced from the original manufacturer or authorized distributors?
All TLD8S40AH 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 TLD8S40AH meets industry standards.
7.What is the process for return or replacement of TLD8S40AH?
All TLD8S40AH units undergo pre-shipment inspection (PSI). If there is an issue with TLD8S40AH, 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 TLD8S40AH part is unused and in its original packaging.
Return procedure for TLD8S40AH:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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