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Taiwan Semiconductor Corporation TLD8S18AH
- Part No.:
- TLD8S18AH
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-218AB
- Datasheet:
-
TLD8S18AH.pdf
- Description:
- TVS DIODE 18VWM 29.2VC DO218AB
- Quantity:
- Payment:
- Shipping:
Inventory:4,797
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Product details
Overview
TLD8S18AH from Taiwan Semiconductor is a unidirectional transient voltage suppressor (TVS) diode in DO-218AB package, designed for automotive load dump protection. It features a 18.0 V working stand-off voltage (VWM), 20.0–22.1 V breakdown voltage (VBR) at 5 mA, 29.2 V clamping voltage (VC) at 226 A peak impulse current, and 6600 W peak pulse power (10/1000 µs), operating up to TJ = 175 °C.
For engineers reviewing the TLD8S18AH datasheet, TLD8S18AH pinout, TLD8S18AH application, or TLD8S18AH equivalent, key selection criteria include load dump surge compliance (ISO 7637-2), high-temperature junction capability, unidirectional polarity marking, and DO-218AB thermal performance with RθJC = 0.8 °C/W under ideal heatsink conditions.
Technical Context
The TLD8S18AH implements a silicon avalanche diode structure optimized for fast response to high-energy transients in 12 V and 24 V automotive electrical systems. Its junction passivation design ensures stable VBR temperature coefficient (αT = 0.083 %/°C) and robust operation across –55 °C to +175 °C junction range.
It meets ISO 7637-2 (Load Dump Pulse 5a/5b) and ISO 16750-2 surge requirements, while delivering 226 A peak impulse current handling and 29.2 V clamping at that level - critical for protecting downstream DC-DC converters, microcontrollers, and CAN transceivers from battery line surges.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 18.0 V - Maximum continuous reverse operating voltage before conduction begins; sets system nominal bus voltage compatibility (e.g., 12 V/24 V automotive). |
| VBR (min/max) | 20.0 / 22.1 V at IT = 5 mA - Confirmed avalanche onset range; ensures predictable turn-on margin above VWM for reliable surge initiation. |
| VC @ IPPM | 29.2 V at 226 A (10/1000 µs) - Clamped voltage during worst-case surge; defines maximum stress on protected ICs. |
| PPPM (10/1000 µs) | 6600 W - Peak surge power handling capacity; validates suitability for severe load dump events per ISO 7637-2. |
| TJ max | +175 °C - Maximum junction temperature rating; enables placement near hot engine compartments without derating. |
| RθJC | 0.8 °C/W - Junction-to-case thermal resistance; supports high-power dissipation when mounted to heatsink or copper plane. |
| IR @ VWM | 10 µA at 25 °C - Low leakage current ensures minimal standby power loss in always-on vehicle modules. |
Pinout & Package
Package: DO-218AB - Surface-mount molded plastic case with matte tin-plated leads, UL 94V-0 rated, JESD201 Class 2 whisker compliant, polarity marked by cathode band.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward current entry (uni-directional) | Connected to ground or low-side return path; enables clamping of positive transients on power rail. |
| Cathode | Reverse-biased terminal (marked) | Connected to protected power line (e.g., battery+); conducts avalanche current during overvoltage events. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive-grade reliability including temperature cycling, HTRB, and ESD robustness - required for front-end power protection in ECUs. |
| Junction passivation technology | Stabilizes VBR drift and leakage over lifetime and temperature - critical for long-term surge immunity in 15+ year vehicle service life. |
| Meets ISO 7637-2 & ISO 16750-2 | Complies with standardized load dump and supply voltage variation test profiles - eliminates need for additional external filtering in OEM designs. |
| IEC 61000-4-2 Level 4 & ISO 10605 L4 | Withstands 8 kV contact / 15 kV air ESD strikes - protects against human-body-model and machine-model electrostatic discharges in assembly and field use. |
| DO-218AB mechanical robustness | 2.691 g mass and J-STD-020 Level 1 moisture sensitivity enable standard reflow without popcorn risk - simplifies SMT manufacturing. |
Applications
| Engine Control Unit (ECU) Power Input Protection | Body Control Module (BCM) Battery Line Protection |
|---|---|
Use Scenario: Protects 5 V/3.3 V domain regulators and MCU I/O from load dump surges during alternator regulation failure in gasoline/diesel vehicles. IC Role / Device Role / Timing Role: Unidirectional TVS placed between battery rail and input filter capacitor; clamps within nanoseconds to limit voltage excursion below 30 V. Use Value: Prevents latch-up or permanent damage to automotive-grade MCUs (e.g., Infineon AURIX, NXP S32K) during 12 V system load dump events up to 6600 W. | Use Scenario: Shields LIN transceivers, door lock actuators, and interior lighting drivers from battery line transients during jump-start or alternator ripple. IC Role / Device Role / Timing Role: Primary surge clamp on 12 V main supply rail upstream of DC-DC converter; operates at TJ ≤ 175 °C in under-hood mounting locations. Use Value: Enables BCM designs to meet OEM-specific ISO 7637-2 Pulse 5a (12 V) and Pulse 5b (24 V) requirements without adding bulkier discrete solutions. |
| ADAS Camera Power Supply Protection | Electric Power Steering (EPS) ECU Input Stage |
Use Scenario: Secures image sensor power rails and serializer interfaces against ignition-induced transients and battery disconnect spikes in rear-view/front-view cameras. IC Role / Device Role / Timing Role: Fast-response TVS placed adjacent to camera module's PMIC input; clamps sub-30 V to preserve signal integrity of GMSL or FPD-Link III links. Use Value: Maintains uninterrupted video streaming during engine cranking and stop-start cycles due to low IR (10 µA) and stable VBR temperature coefficient (0.083 %/°C). | Use Scenario: Guards motor driver gate supplies and position sensor interfaces from high-current switching noise and load dump in EPS control units. IC Role / Device Role / Timing Role: High-power TVS on 12 V auxiliary rail feeding EPS MCU and gate drivers; thermally coupled to aluminum housing via DO-218AB case. Use Value: Supports continuous operation at 175 °C junction temperature - essential for EPS modules mounted near steering column or electric motor housing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ18A | Lower PPPM (400 W), smaller SMA package (RθJC ≈ 50 °C/W), VBR = 20.0–22.2 V, same VWM = 18 V | Not suitable for ISO 7637-2 load dump; limited to lower-energy ESD/surge events in non-automotive or low-risk subsystems | Select only for cost-sensitive consumer or industrial applications where 6600 W surge immunity is not required. |
| SMCJ18A | Higher PPPM (1500 W), larger SMC package (RθJC ≈ 10 °C/W), VBR = 20.0–22.2 V, same VWM = 18 V | Meets ISO 7637-2 Pulse 1/2 but not Pulse 5; insufficient for full load dump protection in modern 12 V/24 V automotive systems | Consider for mid-tier automotive modules (e.g., HVAC controls) where partial surge coverage suffices and DO-218AB footprint is unavailable. |
Compared with SMAJ18A and SMCJ18A, the TLD8S18AH delivers 4.4× and 4.4× higher peak pulse power respectively, with superior thermal resistance (0.8 °C/W vs. ~10–50 °C/W), enabling direct integration into high-reliability automotive front-end protection without external heatsinking.
Availability
TLD8S18AH is available at Aetrix Electronics and suitable for automotive ECU power input protection, body control module surge suppression, and ADAS camera supply stabilization requiring stable component supply across extended temperature and high-surge environments.
Supply support for TLD8S18AH 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 power discrete devices, TVS diodes, and automotive-qualified components since 1995.
The TLD8S series is engineered specifically for high-energy automotive transient suppression, targeting ISO 7637-2 load dump compliance and AEC-Q101 reliability in engine bay and chassis-mounted electronic control units.
FAQ
What is the clamping voltage of the TLD8S18AH at its rated peak impulse current?
The TLD8S18AH has a maximum clamping voltage (VC) of 29.2 V at 226 A peak impulse current with a 10/1000 µs waveform. This value is measured under standardized test conditions and defines the upper voltage limit imposed on protected circuitry during a worst-case surge event. The TLD8S18AH maintains this clamping performance consistently across its qualified temperature range.
Is the TLD8S18AH unidirectional or bidirectional?
The TLD8S18AH is a unidirectional TVS diode, indicated by the "H" suffix (vs. "CAH" for bidirectional variants). It is intended for protection of positive-polarity transients on DC power lines, with cathode connected to the protected rail and anode to ground. Polarity is marked on the DO-218AB package with a visible cathode band.
Does the TLD8S18AH meet AEC-Q101 qualification standards?
Yes, the TLD8S18AH is AEC-Q101 qualified, having passed stress tests including high-temperature reverse bias (HTRB), temperature cycling, and mechanical shock. This qualification confirms its suitability for automotive applications where long-term reliability under harsh environmental conditions is mandatory - a requirement explicitly stated in the official TSC documentation for the TLD8S18AH.
What is the thermal resistance from junction to case (RθJC) for the TLD8S18AH?
The TLD8S18AH has a typical junction-to-case thermal resistance (RθJC) of 0.8 °C/W when mounted to an ideal heatsink. This low value enables efficient heat transfer from the silicon die to the PCB copper or metal housing, supporting sustained power dissipation during repetitive surge events. The RθJC is specified in the Thermal Performance section of the TLD8S18AH datasheet.
Can the TLD8S18AH be used in 24 V automotive systems?
Yes, the TLD8S18AH is suitable for 24 V automotive systems, particularly for protecting auxiliary 12 V domains or low-voltage subsystems powered from a 24 V main bus via DC-DC conversion. Its 18.0 V VWM provides adequate margin above nominal 12 V operation while maintaining fast response to load dump transients defined in ISO 7637-2 for both 12 V and 24 V platforms. The TLD8S18AH's TJ = 175 °C rating further supports under-hood deployment.
TLD8S18AH 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):
- 18V
- Voltage - Breakdown (Min):
- 20V
- Voltage - Clamping (Max) @ Ipp:
- 29.2V
- Current - Peak Pulse (10/1000µs):
- 226A
- 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
TLD8S18AH FAQ
1.How can I place an order for TLD8S18AH through Aetrix?
Please submit a Request for Quotation (RFQ) for TLD8S18AH 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 TLD8S18AH reliable?
The price and inventory of TLD8S18AH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TLD8S18AH is usually 5 days.
3.What payment methods are accepted for TLD8S18AH?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TLD8S18AH transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TLD8S18AH?
TLD8S18AH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TLD8S18AH 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 TLD8S18AH?
For technical support, including TLD8S18AH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TLD8S18AH requirements.
6.How does Aetrix verify that TLD8S18AH is sourced from the original manufacturer or authorized distributors?
All TLD8S18AH 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 TLD8S18AH meets industry standards.
7.What is the process for return or replacement of TLD8S18AH?
All TLD8S18AH units undergo pre-shipment inspection (PSI). If there is an issue with TLD8S18AH, 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 TLD8S18AH part is unused and in its original packaging.
Return procedure for TLD8S18AH:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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