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Taiwan Semiconductor Corporation SMAJ22A
- Part No.:
- SMAJ22A
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ22A.pdf
- Description:
- TVS DIODE 22VWM 35.5VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:4,659
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Product details
Overview
SMAJ22A from Taiwan Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode in DO-214AC (SMA) package, designed for robust overvoltage protection in DC power rails. It features a 22 V working stand-off voltage (VWM), 24.4–26.9 V breakdown voltage (VBR @ 1 mA), and clamps transients to ≤35.5 V at 11.3 A peak pulse current (10/1000 µs waveform), delivering 400 W peak pulse power for automotive and industrial SMPS input stages.
For engineers reviewing the SMAJ22A datasheet, SMAJ22A pinout, SMAJ22A application, or SMAJ22A equivalent, key selection criteria include its unidirectional polarity, 1 µA max reverse leakage at 22 V, -55°C to +150°C operating junction temperature, and compliance with ISO 7637-2 Pulse 1/2a/2b/3a/3b for automotive load-dump and switching surge immunity.
Technical Context
The SMAJ22A operates as a clamping-type TVS diode using an avalanche breakdown mechanism to divert transient energy away from sensitive downstream circuitry. Its glass-passivated junction ensures stable VBR tolerance and low leakage, while the DO-214AC package provides thermal performance suitable for 1 W steady-state dissipation and 40 A non-repetitive forward surge capability.
It responds to fast transients in <1.0 ps (0 V to VBR,min) and maintains clamping performance across ambient temperatures up to +150°C, with derating per Fig.2. The device is rated for moisture sensitivity level 1 (J-STD-020) and meets RoHS and halogen-free (IEC 61249-2-21) requirements.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 22 V - Maximum continuous DC or RMS voltage the device blocks without conduction |
| VBR @ IT=1 mA | 24.4–26.9 V - Breakdown initiates within this range, defining reliable turn-on threshold |
| VC @ IPPM=11.3 A | ≤35.5 V - Clamped voltage during 10/1000 µs surge, limiting stress on protected ICs |
| IR @ VWM | ≤1 µA - Ultra-low leakage preserves efficiency in high-impedance bias networks |
| PPK | 400 W - Peak pulse power handling (10/1000 µs), sufficient for ISO 7637-2 Pulse 1 & 2b |
| TJ Range | -55°C to +150°C - Enables deployment in under-hood automotive and industrial environments |
| Package | DO-214AC (SMA) - Standardized surface-mount outline with cathode band marking and J-STD-002 solderability |
Pinout & Package
DO-214AC (SMA) is a two-terminal, unidirectional surface-mount package with molded epoxy case, matte tin-plated leads, and visible cathode band indicating the cathode terminal. Polarity is marked per device orientation; terminals are not interchangeable.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Transient current entry point (for reverse-biased operation) | Connected to protected line; conducts only during overvoltage events above VBR |
| Cathode | Transient current exit point (marked with band) | Connected to ground or lower-potential rail; completes clamping path during surge |
Key Features
| Feature | Design Value |
|---|---|
| Fast response time | <1.0 ps (0 V to VBR,min) enables suppression of nanosecond-scale ESD and switching spikes before damage occurs |
| Glass passivated junction | Ensures tight VBR tolerance (±5% typical), stable leakage, and long-term reliability under thermal cycling |
| ISO 7637-2 compliance | Validated for Pulse 1 (inductive load dump), Pulse 2a/2b (switching transients), and Pulse 3a/3b (line impedance coupling) |
| Moisture sensitivity level 1 | Zero bake requirement prior to reflow; compatible with standard SMT assembly processes without floor-life restrictions |
Applications
| Switching Mode Power Supply (SMPS) Input Protection | Automotive Body Control Module (BCM) Power Rail |
|---|---|
Use Scenario: Protects AC/DC adapter front-end rectifier and bulk capacitor from line surges and lightning-induced transients. IC Role / Device Role / Timing Role: Unidirectional clamping TVS placed between input line and chassis ground, conducting only during overvoltage events. Use Value: Limits peak voltage to ≤35.5 V during 400 W 10/1000 µs surges, preventing MOSFET gate oxide rupture and bulk capacitor overvoltage failure. | Use Scenario: Shields 12 V supply rail in BCM against load-dump pulses (ISO 7637-2 Pulse 5a) and alternator switching noise. IC Role / Device Role / Timing Role: Standby protection element connected across battery feed and ground, activated only during >24.4 V transients. Use Value: Withstands 40 A single half-sine surge (8.3 ms) and clamps 11.3 A transients to safe levels for microcontroller and CAN transceiver power domains. |
| Industrial DC/DC Converter Input Stage | LED Driver Power Input Protection |
Use Scenario: Safeguards isolated DC/DC converter primary-side input from field-wiring induced surges in factory automation systems. IC Role / Device Role / Timing Role: Primary-side transient clamp on 24 V or 48 V bus, positioned upstream of input filter and controller IC. Use Value: Delivers 400 W peak pulse power with ≤1 µA leakage at 22 V, minimizing standby loss while ensuring immunity to repetitive 10/1000 µs transients. | Use Scenario: Protects constant-current LED driver ICs from voltage spikes caused by inductive ballast switching or cable disconnect events. IC Role / Device Role / Timing Role: Unidirectional TVS mounted across input terminals, shunting energy to ground during overvoltage conditions. Use Value: Fast <1.0 ps response and 35.5 V clamping prevent latch-up or gate damage in integrated LED driver MOSFETs operating near 22 V nominal. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ22 | Higher VC = 39.4 V at 10.2 A; wider VBR range (24.4–29.8 V); same package and PPK | Less stringent clamping; suitable where protected circuit has higher voltage margin | Select SMAJ22A when tighter clamping (≤35.5 V) and lower VBR consistency are required for low-voltage ICs. |
| SMBJ22A | Same electrical specs but in larger DO-214AA (SMB) package; higher thermal mass and 1.5 W steady-state rating | Better thermal performance in high-duty-cycle surge environments; requires larger PCB footprint | Choose SMBJ22A for designs needing enhanced power derating margin or legacy SMB layout compatibility. |
Compared with SMAJ22 and SMBJ22A, the SMAJ22A offers the tightest clamping voltage (35.5 V) among 22 V-rated SMA-packaged TVS diodes and optimal balance of surge robustness, leakage control, and board space efficiency for compact 12–24 V systems.
Availability
SMAJ22A is available at Aetrix Electronics and suitable for switching mode power supplies, automotive body control modules, and industrial DC/DC converters requiring stable component supply, consistent parametric performance, and full traceability through J-STD-020-compliant packaging.
Supply support for SMAJ22A 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, MOSFETs, and power management devices.
The SMAJ series was developed specifically for high-reliability transient suppression in automotive and industrial power systems, emphasizing ISO 7637-2 compliance, low leakage, and robust thermal performance in compact surface-mount packages.
FAQ
What is the maximum clamping voltage of the SMAJ22A under standard test conditions?
The SMAJ22A has a maximum clamping voltage (VC) of 35.5 V when subjected to a 10/1000 µs waveform with a peak impulse current (IPPM) of 11.3 A. This value is measured at TA = 25°C and defines the upper voltage limit imposed on protected circuitry during surge events. The SMAJ22A achieves this clamping performance while maintaining unidirectional polarity and DO-214AC package compatibility.
Is the SMAJ22A suitable for bidirectional transient protection applications?
No, the SMAJ22A is a unidirectional TVS diode and is not rated for bidirectional operation. It conducts only when the cathode is at a higher potential than the anode - i.e., during positive transients on the anode side. For bidirectional protection, a part with "CA" suffix (e.g., SMAJ22CA) must be used. The SMAJ22A datasheet explicitly specifies unidirectional configuration and includes a cathode band marking for correct PCB orientation.
What is the reverse leakage current specification for the SMAJ22A at its working stand-off voltage?
The SMAJ22A exhibits a maximum reverse leakage current (IR) of 1 µA when biased at its rated working stand-off voltage (VWM) of 22 V, measured at TA = 25°C. This ultra-low leakage supports high-impedance sensing circuits and minimizes quiescent power loss in always-on systems. The SMAJ22A maintains this specification across its full operating temperature range (-55°C to +150°C), as confirmed in the absolute maximum ratings table.
Does the SMAJ22A meet automotive industry surge immunity standards?
Yes, the SMAJ22A is explicitly rated to meet ISO 7637-2 for automotive transient immunity, covering Pulse 1 (inductive load dump), Pulse 2a/2b (switching transients), and Pulse 3a/3b (capacitive coupling). Its 400 W peak pulse power rating (10/1000 µs), fast <1.0 ps response, and -55°C to +150°C junction temperature range make it suitable for engine control units, body control modules, and infotainment power inputs. The SMAJ22A qualification is documented in Taiwan Semiconductor's U2102 datasheet revision.
What is the package type and mounting compatibility of the SMAJ22A?
The SMAJ22A uses the DO-214AC (SMA) surface-mount package with matte tin-plated leads compliant with J-STD-002 solderability requirements. Its dimensions and pad layout align with IPC-7351B standard for SMA footprints, enabling automated placement and reflow compatibility. The cathode band marking ensures correct polarity orientation during assembly. The SMAJ22A is supplied in 7,500-piece tape-and-reel format, optimized for high-volume SMT production lines.
SMAJ22A 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:
- 35.5V
- Current - Peak Pulse (10/1000µs):
- 11.3A
- Power - Peak Pulse:
- 400W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMAJ22A FAQ
1.How can I place an order for SMAJ22A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ22A 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 SMAJ22A reliable?
The price and inventory of SMAJ22A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ22A is usually 5 days.
3.What payment methods are accepted for SMAJ22A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ22A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ22A?
SMAJ22A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ22A 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 SMAJ22A?
For technical support, including SMAJ22A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ22A requirements.
6.How does Aetrix verify that SMAJ22A is sourced from the original manufacturer or authorized distributors?
All SMAJ22A 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 SMAJ22A meets industry standards.
7.What is the process for return or replacement of SMAJ22A?
All SMAJ22A units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ22A, 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 SMAJ22A part is unused and in its original packaging.
Return procedure for SMAJ22A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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