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Taiwan Semiconductor Corporation SA18AH
- Part No.:
- SA18AH
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-204AC, DO-15, Axial
- Datasheet:
-
SA18AH.pdf
- Description:
- TVS DIODE 18VWM 39.4VC DO204AC
- Quantity:
- Payment:
- Shipping:
Inventory:4,485
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Product details
Overview
SA18AH from Taiwan Semiconductor is a unidirectional AEC-Q101-qualified transient voltage suppressor (TVS) diode in DO-204AC (DO-15) package, rated for 500W peak pulse power at 10/1000μs, with 18V working stand-off voltage (VWM), 20.0–24.4V breakdown voltage (VBR), and 32.2V clamping voltage (VC) at 16.3A peak pulse current - deployed for automotive ESD and load-dump protection in engine control units and body electronics.
For engineers reviewing the SA18AH datasheet, SA18AH pinout, SA18AH application, or SA18AH equivalent, key selection criteria include its AEC-Q101 qualification, 175°C maximum junction temperature, low 1μA reverse leakage at 18V, sub-1ps response time, and DO-15 mechanical compatibility with legacy through-hole PCB layouts.
Technical Context
The SA18AH operates as a unidirectional avalanche diode, triggering when reverse voltage exceeds its 20.0–24.4V breakdown range at 1mA test current, clamping transients to ≤32.2V at 16.3A. Its silicon junction design enables fast response (<1.0ps from 0V to VBR) and stable performance across –55°C to +175°C operating range.
It complies with IEC 61000-4-2 (ESD), IEC 61000-4-4 (EFT), and ISO 7637-2 (load dump) immunity requirements. The device uses pure tin-plated leads, meets JESD201 Class 2 whisker resistance, and is halogen-free per IEC 61249-2-21.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 18 V - Maximum continuous reverse operating voltage before clamping begins; defines safe DC/AC bias margin for protected circuitry. |
| VBR min/max | 20.0 / 24.4 V @ 1 mA - Breakdown voltage range ensures reliable turn-on within automotive supply tolerances. |
| VC @ IPPM | 32.2 V @ 16.3 A - Clamping voltage during 10/1000μs surge; limits downstream IC stress below 33 V. |
| PPK | 500 W - Peak pulse power handling per 10/1000μs waveform; supports ISO 7637-2 Pulse 5a (load dump) suppression. |
| IR @ VWM | <1 μA - Reverse leakage at 18 V; minimizes standby power loss and avoids false triggering in high-impedance nodes. |
| TJ max | +175 °C - Maximum junction temperature; enables under-hood deployment without derating in engine compartments. |
| Response time | <1.0 ps - Time from 0 V to VBR onset; ensures suppression of nanosecond-scale ESD events before IC damage occurs. |
Pinout & Package
Package: DO-204AC (DO-15), axial leaded, epoxy-molded case with UL 94V-0 rating. Cathode indicated by band marking; anode and cathode terminals are non-polarized in layout but functionally asymmetric for unidirectional operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (unmarked end) | Input reference node | Connected to protected line (e.g., 12 V rail); carries surge current into cathode during clamping. |
| Cathode (banded end) | Clamp return path | Connected to ground or low-impedance return; sinks transient energy and establishes clamping reference. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive under-hood use per stress test requirements including HTOL, TC, UHAST, and bond wire pull. |
| 500W 10/1000μs surge rating | Meets ISO 7637-2 Pulse 5a (load dump) with margin; eliminates need for external series impedance in many 12 V systems. |
| 175°C maximum junction temperature | Enables direct placement near heat sources (e.g., power relays, ignition modules) without thermal derating. |
| Sub-1ps response time | Protects high-speed CAN/LIN transceivers and microcontrollers against ESD events faster than typical IC input protection. |
| Halogen-free & RoHS compliant | Meets automotive OEM material compliance mandates (e.g., GMW3172, Ford WSS-M99P9999-A1) and EU environmental directives. |
Applications
| Engine Control Unit (ECU) Power Input | Automotive Body Control Module (BCM) |
|---|---|
Use Scenario: Protects 12 V supply rail of engine control unit against ISO 7637-2 Pulse 5a (load dump) and ESD events during service. IC Role / Device Role / Timing Role: Unidirectional TVS placed between battery feed and LDO/regulator input to clamp surges before they reach sensitive MCU and analog front-end. Use Value: Limits clamped voltage to 32.2 V, well below 36 V absolute maximum rating of common automotive LDOs, preventing regulator latch-up or destruction. | Use Scenario: Shields LIN bus transceiver and window motor driver ICs from EFT and inductive switching transients in door modules. IC Role / Device Role / Timing Role: Mounted at LIN physical layer entry point and motor driver power input to absorb repetitive 5 kHz EFT bursts and relay coil flyback. Use Value: Sub-1ps response ensures clamping initiates before 5 ns rise-time EFT pulses propagate into transceiver inputs, preserving signal integrity. |
| Infotainment Head Unit USB Port | Automotive Lighting Driver Circuit |
Use Scenario: Guards USB VBUS line in head unit against hot-plug ESD and cable discharge events per IEC 61000-4-2 Level 4. IC Role / Device Role / Timing Role: Placed directly at USB connector, upstream of USB switch and PHY, to shunt >8 kV contact ESD strikes to chassis ground. Use Value: 1 μA leakage at 18 V prevents VBUS droop during enumeration; low capacitance preserves USB 2.0 signal integrity up to 480 Mbps. | Use Scenario: Suppresses inductive kickback from LED driver MOSFETs in adaptive front-lighting systems (AFS). IC Role / Device Role / Timing Role: Connected across drain-source of high-side LED switch to clamp flyback voltage during PWM turn-off transitions. Use Value: 500W rating handles repeated 100 A/ms dI/dt transients without degradation; 175°C rating sustains reliability in sealed headlamp enclosures. |
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 | Same DO-214AC package; lower 400W PPK rating; 33.2V VC @ 12.3A; no AEC-Q101 qualification. | Not approved for automotive under-hood use; suitable only for industrial or consumer-grade 12 V systems. | Select SMAJ18A only if AEC-Q101 is not required and 400W surge margin suffices. |
| 1.5KE18A | DO-201AD package; 1500W PPK; 29.2V VC @ 51.2A; higher leakage (5 μA @ 14.4V); no AEC-Q101. | Larger footprint and higher clamping; better for high-energy surges but incompatible with space-constrained automotive PCBs. | Choose 1.5KE18A only when higher surge capacity is critical and board area allows larger DO-201AD mounting. |
Compared with SMAJ18A and 1.5KE18A, SA18AH uniquely combines AEC-Q101 qualification, DO-15 form factor, and precise 32.2V clamping - making it the only drop-in solution for automotive production where qualification, size, and clamping accuracy are jointly constrained.
Availability
SA18AH is available at Aetrix Electronics and suitable for automotive ECU protection, body electronics surge suppression, and lighting driver transient hardening requiring stable component supply across multi-year vehicle production cycles.
Supply support for SA18AH 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 semiconductor manufacturer specializing in discrete power devices, TVS diodes, rectifiers, and automotive-qualified components since 1979.
The SA Series was developed specifically for automotive transient protection, emphasizing AEC-Q101 compliance, high-temperature reliability, and precise clamping performance in compact DO-15 packaging.
FAQ
What is the clamping voltage of SA18AH and how is it measured?
The SA18AH has a maximum clamping voltage (VC) of 32.2 V at 16.3 A peak pulse current, tested per 10/1000 μs waveform (IEC 61000-4-5). This value is guaranteed across –55°C to +125°C ambient and reflects worst-case voltage seen by downstream circuitry during standardized surge events. The SA18AH datasheet specifies this parameter under "Maximum clamping voltage VC@IPPM" in the electrical characteristics table.
Is SA18AH unidirectional or bidirectional, and how can I identify its polarity?
The SA18AH is a unidirectional TVS diode, designed for DC-biased lines like automotive 12 V supplies. Polarity is marked by a cathode band on the DO-204AC (DO-15) package - the banded end is the cathode and must be connected toward ground or low-impedance return. Bidirectional variants in the SA family use "CA" suffix (e.g., SA18CA), which SA18AH does not carry.
Does SA18AH meet AEC-Q101 requirements, and what tests does that include?
Yes, SA18AH is explicitly AEC-Q101 qualified, as confirmed by its "H" suffix in the ordering code and documentation in TSC's SA Series datasheet Version L2105. Qualification covers stress tests including high-temperature operating life (HTOL), temperature cycling (TC), unbiased highly accelerated stress test (UHAST), and bond wire pull - all performed per AEC-Q101 Rev D specifications for discrete semiconductors.
What is the maximum junction temperature rating for SA18AH, and why does it matter in automotive designs?
The SA18AH has a maximum junction temperature (TJ max) of +175°C, enabling reliable operation in under-hood environments such as engine control units and transmission control modules. This rating allows direct mounting near heat sources without thermal derating, unlike standard TVS diodes rated only to +150°C - ensuring long-term stability in high-ambient automotive applications.
How does the response time of SA18AH compare to typical TVS diodes, and what real-world protection benefit does it provide?
The SA18AH achieves a typical response time of less than 1.0 ps from 0 V to VBR, significantly faster than most TVS diodes (typically 0.5–1 ns). This enables effective suppression of ultrafast ESD events (e.g., IEC 61000-4-2 contact discharge) before they reach sensitive inputs of CAN transceivers or microcontrollers - reducing risk of latch-up or latent damage in automotive electronics.
SA18AH Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Taiwan Semiconductor Corporation
- Package/Case:
- DO-204AC, DO-15, Axial
- Series:
- SA
- 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:
- 39.4V
- Current - Peak Pulse (10/1000µs):
- 17.9A
- Power - Peak Pulse:
- 500W
- Power Line Protection:
- No
- Applications:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 175°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Through Hole
- Supplier Device Package:
- DO-204AC (DO-15)
SA18AH FAQ
1.How can I place an order for SA18AH through Aetrix?
Please submit a Request for Quotation (RFQ) for SA18AH 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 SA18AH reliable?
The price and inventory of SA18AH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SA18AH is usually 5 days.
3.What payment methods are accepted for SA18AH?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SA18AH transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SA18AH?
SA18AH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SA18AH 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 SA18AH?
For technical support, including SA18AH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SA18AH requirements.
6.How does Aetrix verify that SA18AH is sourced from the original manufacturer or authorized distributors?
All SA18AH 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 SA18AH meets industry standards.
7.What is the process for return or replacement of SA18AH?
All SA18AH units undergo pre-shipment inspection (PSI). If there is an issue with SA18AH, 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 SA18AH part is unused and in its original packaging.
Return procedure for SA18AH:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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