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Taiwan Semiconductor Corporation SA18H
- Part No.:
- SA18H
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-204AC, DO-15, Axial
- Datasheet:
-
SA18H.pdf
- Description:
- 500W, 22.2V, UNIDIRECTIONAL, TVS
- Quantity:
- Payment:
- Shipping:
Inventory:5,094
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Product details
Overview
SA18H 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 maximum clamping voltage (VC) at 16.3A peak pulse current - deployed for automotive ESD and load-dump protection in power supply rails.
For engineers reviewing the SA18H datasheet, SA18H pinout, SA18H application, or SA18H equivalent, this page delivers verified electrical parameters, AEC-Q101 qualification status, clamping performance under standardized surge waveforms, thermal derating behavior, and direct alternatives for automotive-grade transient suppression design.
Technical Context
The SA18H operates as a unidirectional avalanche diode, triggering conduction when reverse voltage exceeds its specified VBR range (20.0–24.4V at 1mA test current), limiting transient energy via low-impedance clamping to ≤32.2V at 16.3A. Its fast response time (<1.0ps from 0V to VBR) ensures protection of downstream ICs against ESD and fast transients.
Designed for automotive environments, SA18H meets AEC-Q101 stress requirements including temperature cycling, humidity bias, and mechanical shock. It features pure tin-plated leads compliant with J-STD-002, UL 94V-0 molding compound, and junction temperature range of –55°C to +175°C - enabling use in under-hood ECUs and body control modules.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 18 V - maximum continuous reverse operating voltage before leakage exceeds 1 μA; defines safe DC rail margin for 12V automotive systems. |
| VBR @ IT=1mA | 20.0–24.4 V - breakdown threshold range; ensures reliable turn-on during transients while avoiding false triggering on normal ripple. |
| VC @ IPPM=16.3A | 32.2 V - clamped voltage during 10/1000μs surge; limits stress on protected 24V-rated components. |
| PPK | 500 W - peak pulse power rating per IEC 61000-4-5; supports robust immunity to coupled lightning surges and ISO 7637-2 Pulse 1/2a/5a. |
| TJ max | +175 °C - maximum junction temperature; enables operation in high-ambient under-hood locations without thermal shutdown. |
| IR @ VWM | <1 μA - reverse leakage at 18V; minimizes standby power loss in always-on vehicle networks. |
Pinout & Package
SA18H is housed in a DO-204AC (DO-15) axial-leaded package with cathode band marking. The device has two terminals: anode and cathode - polarity is marked by a single band on the cathode end. Leads are pure tin-plated and solderable per J-STD-002.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward current entry / Reverse voltage reference | Connected to system ground or low-side return path; establishes reference for clamping action during positive transients on cathode side. |
| Cathode | Transient input / Clamping node | Connected to protected line (e.g., battery rail); conducts surge current to ground when voltage exceeds VBR, limiting VC to 32.2V. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive reliability including HTOL, TC, HAST, and mechanical stress - required for engine control, ADAS, and body electronics. |
| Clamping voltage stability | VC = 32.2V at 16.3A (10/1000μs) with <1% variation across production lot - ensures consistent protection margin across units. |
| Low leakage at VWM | IR < 1μA at 18V - avoids parasitic loading on always-on 12V circuits such as CAN transceivers and real-time clocks. |
| Fast avalanche response | <1.0ps response from 0V to VBR - intercepts ESD events (IEC 61000-4-2) before sensitive gate oxides experience overstress. |
Applications
| Automotive Power Rail Protection | Industrial Sensor Interface Protection |
|---|---|
Use Scenario: Protecting 12V battery-supplied microcontrollers and CAN transceivers in engine control units against ISO 7637-2 Pulse 5a (load dump). IC Role / Device Role / Timing Role: Unidirectional TVS placed between battery rail and local regulator input to clamp transients above 32.2V. Use Value: Prevents latch-up or permanent damage to LDOs and MCU I/Os during alternator field collapse events up to 60V/100ms. | Use Scenario: Safeguarding analog front-end inputs of industrial pressure sensors exposed to inductive switching noise from solenoid valves. IC Role / Device Role / Timing Role: TVS mounted at sensor connector to shunt fast-rising transients (<1ns rise time) before reaching signal conditioning op-amps. Use Value: Maintains ADC accuracy by limiting input overvoltage to ≤32.2V, preserving ±10V full-scale range integrity. |
| LED Lighting Driver Protection | USB-C Power Delivery Line Protection |
Use Scenario: Shielding constant-current LED drivers in automotive headlamps from back-EMF spikes generated by relay-controlled power switching. IC Role / Device Role / Timing Role: SA18H placed across driver output to absorb inductive kickback energy before MOSFET drain overstress occurs. Use Value: Extends MOSFET lifetime by limiting VDS peak to 32.2V, well below 60V rating of typical automotive N-channel switches. | Use Scenario: Protecting USB-C CC and VBUS lines in automotive infotainment systems from ESD and hot-swap transients during cable insertion. IC Role / Device Role / Timing Role: Unidirectional TVS on VBUS line referenced to chassis ground, activated only during overvoltage events above 18V. Use Value: Enables compliance with IEC 61000-4-2 Level 4 (15kV air / 8kV contact) without degrading 20V PD negotiation signaling. |
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 PPK (400W); higher VC (32.4V at 14.3A); no AEC-Q101 qualification. | Not qualified for automotive under-hood use; suitable for industrial/commercial PCBs where qualification is not mandated. | Select SMAJ18A only if AEC-Q101 is unnecessary and board space allows SMA footprint change. |
| 1.5KE18A | DO-201AD package; higher PPK (1500W); larger thermal mass; slower response (~1ns); no AEC-Q101. | Used in legacy industrial power supplies; incompatible with automated DO-15 placement; unsuitable for high-speed ESD. | Choose 1.5KE18A only for non-automotive, high-energy surge scenarios where size and speed are secondary. |
Compared with SMAJ18A and 1.5KE18A, SA18H uniquely combines AEC-Q101 qualification, DO-15 compatibility with existing automotive layouts, 500W surge rating, and sub-1ps response - making it the only drop-in solution for new automotive designs requiring validated reliability and precise clamping.
Availability
SA18H is available at Aetrix Electronics and suitable for automotive ECU design, industrial sensor interface development, and LED lighting driver protection requiring stable component supply and long-term lifecycle support.
Supply support for SA18H 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 MOSFETs - headquartered in Hsinchu, Taiwan.
The SA Series was developed specifically for automotive-grade transient suppression, targeting ISO 7637-2 and IEC 61000-4-5 compliance in harsh environment applications with extended temperature and reliability requirements.
FAQ
What is the AEC-Q101 qualification status of SA18H?
SA18H is explicitly AEC-Q101 qualified per the manufacturer's ordering code suffix "H", confirmed in the SA Series datasheet Version L2105. This includes full stress testing for temperature cycling, high-temperature operating life, and unbiased highly accelerated stress testing - validating its suitability for automotive powertrain and body electronics applications.
Does SA18H support bidirectional transient suppression?
No, SA18H is a unidirectional TVS diode. Its datasheet specifies breakdown and clamping characteristics only for reverse-biased operation, with cathode band marking indicating polarity. For bidirectional protection, SA18CA or SA18A would be required - neither shares the "H" AEC-Q101 qualification of SA18H.
What is the maximum clamping voltage of SA18H under standard surge conditions?
The maximum clamping voltage (VC) of SA18H is 32.2 V at 16.3 A peak pulse current, measured under the 10/1000μs waveform per IEC 61000-4-5. This value is guaranteed across the full operating temperature range and represents the upper limit of voltage seen by protected circuitry during worst-case surge events.
Can SA18H replace SA18 in an existing design?
Yes, SA18H is a direct replacement for SA18 with identical electrical specifications and DO-204AC packaging, differing only in AEC-Q101 qualification and tighter process controls. No PCB or schematic changes are needed; however, SA18H provides enhanced reliability validation for automotive applications where SA18 lacks formal qualification.
What is the junction-to-ambient thermal resistance (RθJA) of SA18H?
The datasheet does not specify RθJA for SA18H. Thermal performance is characterized via steady-state power dissipation (PD = 3 W at TL = 75°C with 9.5mm lead length) and derating curves. For thermal modeling, use the provided pulse derating curve (Fig.2) and assume RθJA ≈ 40°C/W for DO-15 on 10×10 mm copper pads - consistent with industry-standard DO-15 thermal data.
SA18H 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:
- 32.2V
- Current - Peak Pulse (10/1000µs):
- 16.3A
- 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)
SA18H FAQ
1.How can I place an order for SA18H through Aetrix?
Please submit a Request for Quotation (RFQ) for SA18H 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 SA18H reliable?
The price and inventory of SA18H are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SA18H is usually 5 days.
3.What payment methods are accepted for SA18H?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SA18H transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SA18H?
SA18H orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SA18H 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 SA18H?
For technical support, including SA18H datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SA18H requirements.
6.How does Aetrix verify that SA18H is sourced from the original manufacturer or authorized distributors?
All SA18H 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 SA18H meets industry standards.
7.What is the process for return or replacement of SA18H?
All SA18H units undergo pre-shipment inspection (PSI). If there is an issue with SA18H, 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 SA18H part is unused and in its original packaging.
Return procedure for SA18H:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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