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Taiwan Semiconductor Corporation SMAJ24H
- Part No.:
- SMAJ24H
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ24H.pdf
- Description:
- TVS DIODE 24VWM 43VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:3,645
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Product details
Overview
SMAJ24H from Taiwan Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode designed for robust overvoltage protection in DC power rails and signal lines. It features a 24 V working stand-off voltage (VWM), 26.7–32.6 V breakdown voltage (VBR), 43.0 V maximum clamping voltage (VC) at 9.3 A peak pulse current, and 400 W peak pulse power rating (10/1000 µs waveform). It is widely deployed in automotive-grade DC/DC converters and industrial SMPS inputs.
For engineers reviewing the SMAJ24H datasheet, SMAJ24H pinout, SMAJ24H application, or SMAJ24H equivalent, key selection criteria include its AEC-Q101 qualification, DO-214AC (SMA) package compatibility with automated placement, sub-1 ps response time, and ISO 7637-2 Pulse 1/2a/2b/3a/3b compliance for automotive transients.
Technical Context
The SMAJ24H operates as a unidirectional avalanche diode, leveraging glass-passivated junction technology to achieve fast transient response (<1.0 ps from 0 V to VBR min) and low leakage (<1 µA at 24 V). Its clamping behavior is defined by a single-die structure optimized for high-energy surge absorption without thermal runaway under repetitive stress.
It is rated for 150 °C maximum junction temperature and supports bidirectional variants (e.g., SMAJ24CH) via suffix change. The device meets JESD201 Class 2 whisker resistance and UL 94V-0 flammability requirements, confirming suitability for harsh-environment PCB assembly and reflow processes.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 24 V - Maximum continuous reverse operating voltage before significant leakage begins; sets safe DC rail margin. |
| VBR @ IT=1 mA | 26.7–32.6 V - Breakdown threshold range; ensures reliable triggering above normal operating voltage with process tolerance. |
| VC @ IPPM=9.3 A | 43.0 V - Clamped voltage during 10/1000 µs surge; defines worst-case protected-circuit overvoltage exposure. |
| PPPM | 400 W - Peak pulse power handling (10/1000 µs); enables protection against ISO 7637-2 Pulse 1 (inductive load dump) and Pulse 2b (battery disconnect). |
| IR @ VWM | <1 µA - Reverse leakage at 24 V; minimizes standby power loss and avoids false triggering in high-impedance circuits. |
| TJ max | 150 °C - Maximum junction temperature; supports operation in under-hood automotive environments and enclosed industrial enclosures. |
Pinout & Package
Package: DO-214AC (SMA), surface-mount, single-ended cathode-banded configuration. Matte tin-plated leads compliant with J-STD-002 solderability; polarity marked by cathode band on body.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side reference terminal | Connected to ground or low-voltage return path; forms current path during reverse-biased clamping event. |
| Cathode | High-side transient input terminal | Connected to protected line (e.g., 24 V rail); conducts avalanche current when VIN exceeds VBR. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive electronics per stress test requirements (HTOL, TCT, ESD, etc.), enabling use in engine control, body electronics, and ADAS power domains. |
| Glass-passivated junction | Enhances long-term reliability and moisture resistance vs. epoxy-passivated alternatives; critical for extended service life in humid or thermally cycled environments. |
| ISO 7637-2 compliance | Guarantees immunity to standardized automotive transients (Pulse 1: −150 V/2 Ω, Pulse 2b: +100 V/50 Ω), eliminating need for additional external filtering in OEM designs. |
| Moisture sensitivity level 1 | Enables standard SMT reflow without baking or dry-pack handling; reduces manufacturing overhead and avoids popcorning risk. |
| Halogen-free & RoHS compliant | Meets IEC 61249-2-21 and EU RoHS Directive 2011/65/EU; supports green manufacturing and export compliance for global supply chains. |
Applications
| Automotive DC/DC Converter Input | Industrial SMPS Primary Side |
|---|---|
Use Scenario: Protecting 24 V input stage of buck converter in vehicle infotainment head unit against load dump and battery reversal events. IC Role / Device Role / Timing Role: Unidirectional TVS clamp placed between input rail and chassis ground to shunt surge energy before it reaches controller IC and MOSFET gate drivers. Use Value: Limits transient voltage to ≤43.0 V, preserving 40 V-rated input capacitors and preventing latch-up in 3.3 V/5 V LDOs downstream. |
Use Scenario: Safeguarding primary-side rectifier output in 48 V telecom power supply subjected to lightning-induced surges on AC mains feed. IC Role / Device Role / Timing Role: Standoff protector across bulk capacitor terminals, triggered within <1 ps to clamp 1 kV/10 Ω surge waveforms. Use Value: Absorbs 400 W peak pulse without degradation, maintaining system uptime and avoiding costly field returns due to failed front-end rectifiers. |
| LED Driver Power Rail | On-Board Charger (OBC) Control Logic |
Use Scenario: Securing constant-current LED driver IC supply in streetlight fixture exposed to induced surges from nearby switching loads. IC Role / Device Role / Timing Role: Low-leakage (≤1 µA) standoff protector ensuring stable bias for analog current-sense amplifiers and PWM controllers. Use Value: Prevents false dimming or flicker caused by microsecond-scale transients that would otherwise corrupt feedback loop stability. |
Use Scenario: Shielding isolated communication interface (e.g., CAN or SPI) power pins in EV on-board charger against coupling from high-power IGBT switching noise. IC Role / Device Role / Timing Role: Localized rail clamp adjacent to digital isolator VDD, suppressing common-mode transients before they couple into logic thresholds. Use Value: Maintains signal integrity during 100 kHz+ switching transitions, reducing bit errors and eliminating need for redundant error-checking firmware. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ24AH | Lower VBR range (26.7–29.5 V) and lower VC (38.9 V); same package and PPPM. | Better suited for tighter-tolerance 24 V systems where clamping margin must be minimized (e.g., sensitive sensor power rails). | Select SMAJ24AH when design requires lower clamping voltage and can tolerate reduced VBR tolerance; SMAJ24H offers higher VBR margin for noisy environments. |
| SMBJ24H | Same electrical specs but in DO-214AA (SMB) package - 2.5 mm wider, 1.5 mm taller, 2× higher PPPM derating above 75 °C. | Preferred for high-reliability industrial applications requiring enhanced thermal margin and mechanical robustness. | Choose SMBJ24H if board layout allows larger footprint and thermal performance under sustained ambient >85 °C is critical. |
Compared with SMAJ24AH and SMBJ24H, the SMAJ24H delivers optimal balance of compact DO-214AC footprint, AEC-Q101 qualification, and 43.0 V clamping-making it the default choice for space-constrained automotive and industrial 24 V rail protection where cost, size, and qualification alignment are prioritized.
Availability
SMAJ24H is available at Aetrix Electronics and suitable for automotive DC/DC converters, industrial SMPS units, and LED driver power rails requiring stable component supply with full traceability and lifecycle management.
Supply support for SMAJ24H 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 Taiwanese semiconductor manufacturer specializing in discrete power devices, TVS diodes, and rectifiers since 1979.
The SMAJ series was developed specifically for AEC-Q101-compliant automotive and industrial transient suppression, emphasizing high surge robustness, tight parametric consistency, and automated assembly readiness in surface-mount packages.
FAQ
What is the maximum clamping voltage of the SMAJ24H under standard test conditions?
The SMAJ24H has a maximum clamping voltage (VC) of 43.0 V when subjected to a 10/1000 µs waveform with a peak impulse current (IPPM) of 9.3 A. This value is measured per JEDEC standards and defines the upper voltage limit imposed on protected circuitry during surge events. The SMAJ24H maintains this clamping performance across its full operating temperature range (−55 °C to +150 °C), making it suitable for under-hood automotive applications.
Is the SMAJ24H suitable for bidirectional transient protection?
No, the SMAJ24H is a unidirectional TVS diode intended for DC rail protection with defined anode/cathode polarity. For bidirectional applications such as AC lines or data bus protection, the SMAJ24CH variant (with CH suffix) must be used instead. The SMAJ24H's cathode band marking indicates polarity, and reverse connection will result in forward conduction and potential failure. Always verify polarity during PCB layout and assembly.
Does the SMAJ24H meet automotive qualification standards?
Yes, the SMAJ24H is AEC-Q101 qualified, having passed all required stress tests including high-temperature operating life (HTOL), temperature cycling (TCT), electrostatic discharge (HBM/MM), and mechanical shock. This qualification confirms its suitability for automotive powertrain, body electronics, and infotainment systems. The SMAJ24H also complies with ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b, covering key vehicle-level transient threats.
What is the reverse leakage current specification for the SMAJ24H at its working voltage?
The SMAJ24H exhibits a maximum reverse leakage current (IR) of 1 µA when biased at its 24 V working stand-off voltage (VWM). This ultra-low leakage ensures minimal power loss in always-on systems and prevents false triggering in high-impedance sensing circuits. The specification is guaranteed at TA = 25 °C and remains below 5 µA up to 125 °C, supporting reliable operation in thermally demanding environments.
Can the SMAJ24H be used in lead-free reflow processes?
Yes, the SMAJ24H features matte tin-plated leads compliant with J-STD-002 solderability requirements and is rated for standard lead-free reflow profiles (peak temperature up to 260 °C). Its DO-214AC (SMA) package is moisture sensitivity level 1 (per J-STD-020), meaning it can be stored indefinitely at ambient conditions without baking prior to assembly. This simplifies manufacturing logistics and eliminates yield loss from moisture-related defects.
SMAJ24H 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):
- 24V
- Voltage - Breakdown (Min):
- 26.7V
- Voltage - Clamping (Max) @ Ipp:
- 43V
- Current - Peak Pulse (10/1000µs):
- 9.3A
- 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)
SMAJ24H FAQ
1.How can I place an order for SMAJ24H through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ24H 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 SMAJ24H reliable?
The price and inventory of SMAJ24H are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ24H is usually 5 days.
3.What payment methods are accepted for SMAJ24H?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ24H transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ24H?
SMAJ24H orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ24H 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 SMAJ24H?
For technical support, including SMAJ24H datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ24H requirements.
6.How does Aetrix verify that SMAJ24H is sourced from the original manufacturer or authorized distributors?
All SMAJ24H 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 SMAJ24H meets industry standards.
7.What is the process for return or replacement of SMAJ24H?
All SMAJ24H units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ24H, 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 SMAJ24H part is unused and in its original packaging.
Return procedure for SMAJ24H:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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