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Taiwan Semiconductor Corporation SMAJ22H
- Part No.:
- SMAJ22H
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ22H.pdf
- Description:
- TVS DIODE 22VWM 39.4VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:9,881
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Product details
Overview
SMAJ22H from Taiwan Semiconductor is a unidirectional 400W surface-mount transient voltage suppressor (TVS) diode in DO-214AC (SMA) package, with 22V working stand-off voltage (VWM), 24.4–29.8V breakdown voltage (VBR), and 39.4V maximum clamping voltage (VC) at 10.2A peak pulse current under 10/1000μs waveform. It delivers AEC-Q101 qualification and meets ISO 7637-2 Pulse 1/2a/2b/3a/3b for automotive power line protection.
For engineers reviewing the SMAJ22H datasheet, SMAJ22H pinout, SMAJ22H application, or SMAJ22H equivalent, key selection considerations include its 22V VWM rating for 24V rail protection, sub-1ps response time, <1μA leakage above 10V, glass-passivated junction, and UL 94V-0 molding compound - all critical for robust ESD/surge immunity in automotive DC/DC converters and SMPS front-end stages.
Technical Context
The SMAJ22H operates as a unidirectional avalanche diode, leveraging a glass-passivated silicon junction to achieve fast turn-on (<1.0ps from 0V to VBR min) and stable clamping under transient overvoltage events. Its single-die configuration supports bidirectional variants only with CH/CAH suffixes; SMAJ22H itself is strictly unidirectional, marked with cathode band.
It complies with AEC-Q101 stress testing for automotive reliability and satisfies ISO 7637-2 Pulse 1 (inductive load dump simulation), Pulse 2a/2b (battery disconnect & supply interruption), and Pulse 3a/3b (capacitive coupling & line impedance transients). Thermal derating begins above TA = 25°C per Fig.2, with TJ max = 150°C and TSTG = −55 to +150°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 22 V - Maximum continuous reverse operating voltage before conduction; sets threshold for 24V system rail protection. |
| VBR min/max | 24.4 V / 29.8 V at IT = 1 mA - Confirmed avalanche onset range; ensures reliable triggering above normal operating voltage. |
| VC @ IPPM | 39.4 V at 10.2 A (10/1000μs) - Clamped voltage during worst-case surge; limits downstream IC stress to safe levels. |
| PPPM | 400 W (10/1000μs) - Peak pulse power handling; sufficient for ISO 7637-2 Pulse 1 (−100V/0.5Ω/50ms) and Pulse 2a. |
| IR @ VWM | <1 μA - Negligible leakage at rated stand-off; avoids battery drain in always-on automotive modules. |
| Response time | <1.0 ps - Enables suppression of nanosecond-scale ESD and fast transients before sensitive circuitry reacts. |
| Package | DO-214AC (SMA) - Industry-standard surface-mount outline; compatible with automated placement and reflow soldering. |
Pinout & Package
DO-214AC (SMA) package: molded epoxy case with matte tin-plated leads, polarity indicated by cathode band (cathode = banded end), weight ≈ 0.060 g, moisture sensitivity level 1 (J-STD-020).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Non-banded end | Connected to protected line (e.g., 24V rail input); conducts during reverse surge when cathode is at higher potential. |
| Cathode | Banded end | Connected to ground or low-impedance return path; defines unidirectional clamping direction and polarity marking. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive underhood and chassis applications including temperature cycling, HTRB, and ESD testing. |
| Glass-passivated junction | Enhances long-term stability and reduces parameter drift under thermal/humidity stress vs. epoxy-passivated alternatives. |
| ISO 7637-2 compliance | Guarantees performance against standardized automotive transients (Pulse 1/2a/2b/3a/3b) without external filtering. |
| UL 94V-0 flammability rating | Molding compound self-extinguishes within 10 seconds after flame removal - required for automotive cabin and powertrain modules. |
| JESD201 Class 2 whisker resistance | Prevents tin whisker growth under thermal cycling, eliminating risk of latent short circuits in high-reliability systems. |
Applications
| Automotive Power Distribution | Industrial SMPS Input Stage |
|---|---|
Use Scenario: Protection of 24V battery-fed ECUs against load dump and alternator transients. IC Role / Device Role / Timing Role: Unidirectional TVS placed between battery rail and DC/DC converter input. Use Value: Clamps ISO 7637-2 Pulse 1 to ≤39.4V, preventing damage to upstream MOSFETs and controller ICs rated for 40V max. |
Use Scenario: Surge suppression on AC-DC adapter output feeding isolated DC/DC modules. IC Role / Device Role / Timing Role: Standoff-rated TVS absorbing line-induced spikes before regulation stage. Use Value: 22V VWM matches nominal 24V output; 400W PPPM handles repetitive surges without degradation. |
| LED Driver Power Input | On-Board Charger (OBC) Auxiliary Supply |
Use Scenario: Protecting constant-current LED drivers from inductive switching transients in vehicle lighting. IC Role / Device Role / Timing Role: Primary overvoltage clamp on 12V/24V driver input bus. Use Value: Sub-1ps response ensures clamping before LED driver IC latch-up or gate oxide failure occurs. |
Use Scenario: Safeguarding 12V auxiliary supply rails in EV on-board chargers exposed to battery ripple and relay bounce. IC Role / Device Role / Timing Role: Secondary-level TVS on isolated 12V bias supply derived from main HV bus. Use Value: AEC-Q101 qualification and −55°C to +150°C operation ensure reliability across full EV thermal envelope. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Littelfuse SMAJ22A | Lower VBR range (24.4–26.9V), tighter tolerance; same DO-214AC package and 400W rating. | Preferred where tighter breakdown consistency is needed for precise clamping margin control. | Select SMAJ22A if design requires reduced VBR variation; SMAJ22H offers broader VBR spread for cost-sensitive volume production. |
| ON Semiconductor SMAJ22AHE3/A | Same electrical specs and AEC-Q101 qualification; differs in marking code and tape/reel packaging standard. | No functional difference; suitable for dual-sourcing in automotive Tier-1 BOMs requiring second-source validation. | Choose ON's version when supply chain diversification or specific logistics requirements (e.g., E3 tape standard) apply. |
Compared with SMAJ22A and SMAJ22AHE3/A, the SMAJ22H provides identical 22V VWM and 400W surge capability but with a wider VBR range (24.4–29.8V), offering greater process margin at slightly lower test-current consistency - advantageous for high-volume automotive harness assemblies where absolute VBR matching is secondary to cost and availability.
Availability
SMAJ22H is available at Aetrix Electronics and suitable for automotive power distribution, industrial SMPS input protection, and LED driver input surge suppression requiring stable component supply across extended temperature ranges and high-reliability certifications.
Supply support for SMAJ22H 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 MOSFETs for automotive and industrial markets.
The SMAJ series was designed specifically for AEC-Q101-compliant transient protection in 12V/24V automotive subsystems, emphasizing robustness against ISO 7637-2 pulses, low leakage, and automated assembly compatibility.
FAQ
What is the maximum clamping voltage of SMAJ22H under standard 10/1000μs surge conditions?
The SMAJ22H has a maximum clamping voltage (VC) of 39.4 V at 10.2 A peak pulse current under the 10/1000μs waveform. This value is measured per IEC 61000-4-5 and ISO 7637-2 standards and ensures downstream components see no more than 39.4 V during worst-case transients - critical for protecting 40V-rated power MOSFETs and controllers in automotive 24V systems.
Is SMAJ22H suitable for bidirectional transient protection?
No, SMAJ22H is a unidirectional TVS diode, intended for protection against reverse-polarity surges on positive-rail systems. Bidirectional operation requires the SMAJ22CH or SMAJ22CAH variant, which uses symmetrical breakdown characteristics in both directions. Using SMAJ22H in bidirectional configurations risks incomplete clamping during positive transients.
Does SMAJ22H meet automotive qualification standards?
Yes, SMAJ22H is AEC-Q101 qualified and tested per JESD22-A108 for temperature cycling, JESD22-A101 for humidity storage, and JESD22-A114 for ESD (HBM ≥8 kV). It also meets ISO 7637-2 Pulse 1/2a/2b/3a/3b, making it suitable for engine control units, body control modules, and ADAS power supplies.
What is the leakage current specification for SMAJ22H at its working stand-off voltage?
At VWM = 22 V, the SMAJ22H exhibits a maximum reverse leakage current (IR) of 1 μA at 25°C. This ultra-low leakage ensures minimal standby power loss in always-on automotive modules such as telematics control units and gateway ECUs, supporting stringent OEM quiescent current budgets.
Can SMAJ22H be used in place of SMAJ22AH?
No - SMAJ22H and SMAJ22AH are distinct variants: SMAJ22H has a VBR range of 24.4–29.8 V, while SMAJ22AH tightens this to 24.4–26.9 V. Substituting SMAJ22H for SMAJ22AH may result in higher clamping voltage variability and reduced design margin in precision-clamp applications; always verify VBR tolerance requirements before interchange.
SMAJ22H 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):
- 22V
- Voltage - Breakdown (Min):
- 24.4V
- Voltage - Clamping (Max) @ Ipp:
- 39.4V
- Current - Peak Pulse (10/1000µs):
- 10.2A
- 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)
SMAJ22H FAQ
1.How can I place an order for SMAJ22H through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ22H 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 SMAJ22H reliable?
The price and inventory of SMAJ22H are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ22H is usually 5 days.
3.What payment methods are accepted for SMAJ22H?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ22H transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ22H?
SMAJ22H orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ22H 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 SMAJ22H?
For technical support, including SMAJ22H datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ22H requirements.
6.How does Aetrix verify that SMAJ22H is sourced from the original manufacturer or authorized distributors?
All SMAJ22H 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 SMAJ22H meets industry standards.
7.What is the process for return or replacement of SMAJ22H?
All SMAJ22H units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ22H, 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 SMAJ22H part is unused and in its original packaging.
Return procedure for SMAJ22H:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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