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Taiwan Semiconductor Corporation SMAJ43AH
- Part No.:
- SMAJ43AH
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ43AH.pdf
- Description:
- TVS DIODE 43VWM 69.4VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:7,307
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Product details
Overview
SMAJ43AH from Taiwan Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode in DO-214AC (SMA) package, designed for automotive-grade overvoltage protection. It features a 43 V working stand-off voltage (VWM), 47.8–52.8 V breakdown voltage (VBR) at 1 mA test current, and clamps transients to ≤69.4 V at 5.8 A peak impulse current under 10/1000 µs waveform - ideal for protecting DC/DC converter inputs in automotive infotainment systems.
For engineers reviewing the SMAJ43AH datasheet, SMAJ43AH pinout, SMAJ43AH application, or SMAJ43AH equivalent, key selection criteria include its AEC-Q101 qualification, 400 W peak pulse power rating (10/1000 µs), low leakage (<1 µA @ 43 V), ISO 7637-2 Pulse 1/2a/2b/3a/3b compliance, and unidirectional polarity with cathode band marking.
Technical Context
The SMAJ43AH operates as a unidirectional avalanche diode, leveraging glass-passivated junction technology for stable breakdown behavior and fast response (<1.0 ps from 0 V to VBR min). Its clamping action begins at VBR and sustains up to 69.4 V at rated IPPM, limiting surge energy dissipation across protected ICs or MOSFET gates.
Designed for automotive environments, it supports operating junction temperatures from –55 °C to +150 °C, meets JESD201 Class 2 whisker resistance, and uses matte tin-plated leads compliant with J-STD-002 solderability standards - enabling reliable reflow assembly in high-reliability power rail protection circuits.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 43 V - maximum continuous reverse voltage before leakage exceeds 1 µA; defines safe operating margin below clamping threshold |
| VBR min/max | 47.8 V / 52.8 V @ 1 mA - guaranteed avalanche initiation range; ensures predictable turn-on across production lots |
| VC @ IPPM | 69.4 V @ 5.8 A (10/1000 µs) - maximum clamped voltage during worst-case surge; determines protected circuit's voltage stress limit |
| PPPM | 400 W - peak pulse power handling per 10/1000 µs waveform; enables robust protection against load dump and inductive switching events |
| IR @ VWM | <1 µA - ultra-low reverse leakage at rated stand-off; minimizes standby power loss in always-on automotive modules |
| TJ max | +150 °C - maximum junction temperature; supports placement near hot components like power inductors or MOSFETs |
Pinout & Package
DO-214AC (SMA) surface-mount package: single-ended, two-terminal construction with cathode band marking on one end; 0.060 g weight; UL 94V-0 molding compound; matte tin-plated leads.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current entry point in forward bias; connected to protected circuit ground or low-side return path | Provides low-impedance path to ground during transient clamp; must be routed with minimal inductance to avoid voltage overshoot |
| Cathode (marked) | Protected line connection; reverse-biased during normal operation | Connects to the rail requiring protection (e.g., 48 V input); polarity marking prevents incorrect orientation in automated placement |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive electronics per stress test requirements including HTOL, TC, UHAST, and ESD - enables use in ADAS, body control, and infotainment ECUs without additional qualification |
| Glass passivated junction | Stable VBR tolerance and low leakage over temperature and lifetime; eliminates risk of junction degradation under repeated surge cycling |
| ISO 7637-2 compliance | Withstands Pulse 1 (inductive load disconnect), Pulse 2a/2b (switching transients), and Pulse 3a/3b (capacitive coupling) - satisfies OEM-level EMC immunity requirements |
| Fast response time | <1.0 ps rise-to-breakdown - reacts before sensitive downstream logic or analog circuitry can be damaged by fast-rising ESD or EFT events |
Applications
| Automotive Infotainment Power Input | On-Board DC/DC Converter Protection |
|---|---|
Use Scenario: Protecting 48 V input stage of head unit DC/DC converter against load dump and jump-start surges. IC Role / Device Role / Timing Role: Unidirectional TVS placed between input rail and chassis ground to clamp transients before they reach buck controller IC. Use Value: Limits voltage to ≤69.4 V during 400 W pulses, preventing gate oxide rupture in high-side MOSFETs and ensuring system-level ISO 7637-2 compliance. | Use Scenario: Safeguarding secondary-side 12 V output of isolated flyback converter from reflected transients and cross-coupling noise. IC Role / Device Role / Timing Role: TVS mounted at output connector to absorb coupled spikes from adjacent high-current lines during CAN/LIN bus activity. Use Value: Sub-µA leakage preserves light-load efficiency; DO-214AC footprint allows placement directly at board edge I/O points without layout compromise. |
| Industrial SMPS Front-End | LED Driver Input Stage |
Use Scenario: Guarding AC/DC adapter primary-side bulk capacitor charging path against lightning-induced surges on 24 V DC input lines. IC Role / Device Role / Timing Role: Standoff-rated TVS absorbing repetitive 10/1000 µs transients while maintaining <1 µA leakage at 43 V nominal. Use Value: 400 W rating handles multiple surge events without parametric shift; AEC-Q101 qualification assures long-term reliability in unattended equipment. | Use Scenario: Protecting constant-current LED driver IC from voltage reversals and inductive kickback during dimming FET switching. IC Role / Device Role / Timing Role: Unidirectional clamp referenced to driver ground, shunting negative transients away from sensitive analog feedback pins. Use Value: Cathode-band polarity ensures correct orientation during pick-and-place; 69.4 V clamping prevents latch-up in op-amp-based current sense circuitry. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ43A | Same VWM (43 V), but VBR min/max = 47.8–58.4 V (wider tolerance vs. SMAJ43AH's 47.8–52.8 V); no AEC-Q101 qualification | Not approved for automotive use; suitable only for industrial or consumer-grade 43 V rail protection | Select SMAJ43A only if AEC-Q101 is not required and wider VBR tolerance is acceptable for system margin analysis. |
| SMBJ43AH | Same electrical specs (VWM=43 V, VBR=47.8–52.8 V, VC=69.4 V), but SMB package (DO-214AA) - 2.5 mm wider body, higher thermal mass | Lower power density; better thermal performance in high-ambient or high-duty-cycle surge environments | Choose SMBJ43AH when PCB layout allows larger footprint and improved thermal derating is needed over extended temperature ranges. |
Compared with SMAJ43A and SMBJ43AH, the SMAJ43AH uniquely combines AEC-Q101 qualification, tight VBR tolerance (±5.2%), and DO-214AC footprint - making it the optimal choice for space-constrained automotive modules requiring certified reliability and precise clamping predictability.
Availability
SMAJ43AH is available at Aetrix Electronics and suitable for automotive infotainment systems, on-board DC/DC converters, and industrial SMPS designs requiring stable component supply with full traceability and lifecycle support.
Supply support for SMAJ43AH 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 discrete semiconductor manufacturer headquartered in Hsinchu, Taiwan, specializing in TVS diodes, rectifiers, and power devices since 1979.
The SMAJ series is part of TSC's AEC-Q101-qualified transient suppression portfolio, engineered specifically for automotive power rail protection where precision clamping, low leakage, and ISO 7637-2 compliance are mandatory.
FAQ
What is the clamping voltage of SMAJ43AH under standard 10/1000 µs surge conditions?
The SMAJ43AH clamps to a maximum of 69.4 V when subjected to its rated peak impulse current of 5.8 A using the 10/1000 µs waveform. This value is measured at TA = 25°C and represents the upper limit of voltage seen by downstream circuitry during transient events - critical for ensuring protected ICs remain within absolute maximum ratings. The SMAJ43AH achieves this clamping performance while maintaining sub-µA leakage at its 43 V working stand-off voltage.
Is SMAJ43AH suitable for bidirectional transient protection?
No, SMAJ43AH is a unidirectional TVS diode intended for protection of positive-polarity DC rails only. Its cathode band marking indicates polarity-sensitive installation. For bidirectional applications such as data lines or AC-coupled signals, a bipolar variant like SMAJ43CH (with CH suffix) must be used instead. The SMAJ43AH's electrical characteristics apply exclusively in reverse bias; forward conduction follows standard silicon diode behavior with VF ≈ 3.5 V at 25 A.
Does SMAJ43AH meet automotive qualification standards?
Yes, SMAJ43AH is explicitly AEC-Q101 qualified and meets ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b requirements. It also complies with JESD201 Class 2 whisker resistance, J-STD-020 moisture sensitivity level 1, and RoHS/halogen-free standards per IEC 61249-2-21 - confirming its suitability for under-hood and cabin-mounted automotive ECUs without additional qualification testing.
What is the thermal derating behavior of SMAJ43AH above 25°C ambient?
SMAJ43AH's peak pulse power rating decreases linearly above TA = 25°C per Figure 2 in the official datasheet: at 75°C ambient, its 400 W rating drops to approximately 280 W; at 125°C, it falls to ~140 W. This derating applies to non-repetitive pulses and must be factored into system-level surge margin calculations - especially in engine control units or power distribution modules where ambient temperatures exceed 85°C.
How does the breakdown voltage tolerance of SMAJ43AH compare to the standard SMAJ43H variant?
SMAJ43AH has a tighter VBR tolerance of 47.8–52.8 V (±5.2% around nominal 50.3 V), whereas SMAJ43H specifies 47.8–58.4 V (±11.1%). This narrower spread improves design predictability for clamping margin analysis and reduces need for worst-case simulation sweeps. Both share identical VWM (43 V), IPPM (5.8 A), and VC (69.4 V), but only SMAJ43AH carries AEC-Q101 qualification - making it the preferred choice for automotive applications demanding precision and certification.
SMAJ43AH Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Taiwan Semiconductor Corporation
- Package/Case:
- DO-214AC, SMA
- Series:
- SMAJ
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 43V
- Voltage - Breakdown (Min):
- 47.8V
- Voltage - Clamping (Max) @ Ipp:
- 69.4V
- Current - Peak Pulse (10/1000µs):
- 5.8A
- Power - Peak Pulse:
- 400W
- Power Line Protection:
- No
- Applications:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMAJ43AH FAQ
1.How can I place an order for SMAJ43AH through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ43AH 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 SMAJ43AH reliable?
The price and inventory of SMAJ43AH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ43AH is usually 5 days.
3.What payment methods are accepted for SMAJ43AH?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ43AH transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ43AH?
SMAJ43AH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ43AH 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 SMAJ43AH?
For technical support, including SMAJ43AH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ43AH requirements.
6.How does Aetrix verify that SMAJ43AH is sourced from the original manufacturer or authorized distributors?
All SMAJ43AH 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 SMAJ43AH meets industry standards.
7.What is the process for return or replacement of SMAJ43AH?
All SMAJ43AH units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ43AH, 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 SMAJ43AH part is unused and in its original packaging.
Return procedure for SMAJ43AH:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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