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Taiwan Semiconductor Corporation SMAJ24
- Part No.:
- SMAJ24
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ24.pdf
- Description:
- 400W, 29.7V, 10%, UNIDIRECTIONAL
- Quantity:
- Payment:
- Shipping:
Inventory:8,501
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Product details
Overview
SMAJ24 from Taiwan Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode designed for primary-side overvoltage protection in DC power rails. It features a 24 V working stand-off voltage (VWM), 26.7–32.6 V breakdown voltage (VBR) at 1 mA test current, and clamps up to 43.0 V at 9.3 A peak impulse current under 10/1000 µs waveform - enabling robust surge immunity in industrial power adapters and automotive ECUs.
For engineers reviewing the SMAJ24 datasheet, SMAJ24 pinout, SMAJ24 application, or SMAJ24 equivalent, key selection criteria include its DO-214AC (SMA) package compatibility with automated SMT lines, sub-1 ps response time, <1 µA reverse leakage above VWM, ISO 7637-2 Pulse 1/2a/2b/3a/3b compliance, and 400 W peak pulse power rating at 25°C.
Technical Context
The SMAJ24 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 stable clamping performance across -55°C to +150°C junction temperature range. Its single-die DO-214AC construction ensures low parasitic inductance and repeatable surge handling.
It delivers 400 W peak pulse power per 10/1000 µs waveform at 25°C (derated linearly above ambient), with maximum clamping voltage VC of 43.0 V at IPPM = 9.3 A. Reverse leakage remains ≤1 µA at rated VWM = 24 V, supporting low-power standby integrity in always-on systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 24 V - Maximum continuous DC or RMS voltage the device blocks without conduction; sets operating rail margin before clamping. |
| VBR min/max | 26.7 V / 32.6 V at IT = 1 mA - Confirmed avalanche onset range; defines minimum trigger threshold for transient suppression. |
| VC @ IPPM | 43.0 V at 9.3 A - Clamped voltage during 10/1000 µs surge; determines maximum stress imposed on downstream ICs. |
| PPPM | 400 W (10/1000 µs) - Peak surge energy absorption capability; validates suitability for IEC 61000-4-5 Level 3/4 and ISO 7637-2 Pulse 5a. |
| IR @ VWM | ≤1 µA - Ultra-low reverse leakage ensures minimal quiescent current drain in battery-backed or energy-harvesting circuits. |
| Package | DO-214AC (SMA) - Standardized surface-mount outline with 0.060 g mass; compatible with J-STD-002 solderability and JESD201 Class 2 whisker resistance. |
Pinout & Package
DO-214AC (SMA) package: molded epoxy case with matte tin-plated leads, polarity indicated by cathode band; meets UL 94V-0 flammability rating and J-STD-020 moisture sensitivity level 1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Input/Line side | Connected to protected power rail (e.g., +24 V input); conducts during reverse-biased transients. |
| Cathode | Ground reference | Connected to system ground or low-impedance return path; establishes clamping reference and polarity marking. |
Key Features
| Feature | Design Value |
|---|---|
| Glass-passivated junction | Enables stable VBR tolerance and long-term reliability under thermal cycling and humidity exposure. |
| Sub-1 ps response time | Ensures clamping activation before nanosecond-scale ESD or lightning-induced edge transients propagate into sensitive circuitry. |
| ISO 7637-2 compliance | Validates robustness against automotive load dump (Pulse 5a), supply interruption (Pulse 2b), and coupled noise (Pulse 1/3a/3b). |
| RoHS & halogen-free | Meets IEC 61249-2-21 and EU RoHS Directive 2011/65/EU for environmentally compliant manufacturing and end-of-life processing. |
Applications
| Industrial Power Adapter Protection | Automotive Body Control Module (BCM) |
|---|---|
Use Scenario: 24 V DC input stage of DIN-rail mounted AC/DC adapter exposed to line surges and hot-swap events. IC Role / Device Role / Timing Role: Primary overvoltage clamp placed between input connector and upstream fuse/EMI filter. Use Value: Limits transient voltage to ≤43.0 V, protecting downstream PWM controllers and optocouplers from damage during 400 W surges. |
Use Scenario: 12/24 V power rail in BCM controlling door locks, lighting, and window motors. IC Role / Device Role / Timing Role: Unidirectional TVS on battery feed line to suppress load dump pulses per ISO 7637-2 Pulse 5a. Use Value: Withstands 9.3 A peak impulse at 43.0 V clamping, preventing latch-up or burnout in microcontroller power domains. |
| On-board DC/DC Converter Input | LED Driver Supply Rail |
Use Scenario: 24 V input to isolated flyback or buck converter powering isolated sensor interfaces. IC Role / Device Role / Timing Role: First-line transient suppressor ahead of input capacitor and controller IC. Use Value: Fast <1 ps response prevents overshoot propagation into switching controller, maintaining regulation stability during EFT bursts. |
Use Scenario: Constant-current LED driver board in streetlight or signage applications subject to grid switching transients. IC Role / Device Role / Timing Role: Rail clamp on high-side switch supply to protect gate drivers and current sense amplifiers. Use Value: 24 V VWM aligns with nominal LED string voltage; 43.0 V VC ensures MOSFET gate oxide remains within safe margin. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ24A | Narrower VBR range (26.7–29.5 V) and lower clamping voltage (38.9 V at 10.3 A); tighter tolerance improves precision clamping. | Better suited for systems requiring tighter voltage margin control, e.g., 3.3 V logic-supplied microcontrollers with 40 V absolute max ratings. | Select SMAJ24A when clamping voltage headroom is critical and VBR consistency across production lots is prioritized. |
| SMBJ24 | Same VWM/VBR/VC specs but in larger DO-214AA (SMB) package; higher thermal mass supports 600 W peak power rating. | Preferred where PCB layout allows larger footprint and higher surge duty cycles occur, such as in telecom power shelves or solar charge controllers. | Choose SMBJ24 only if mechanical space permits and sustained surge repetition rate exceeds SMAJ24's 400 W derating curve limits. |
Compared with SMAJ24, SMAJ24A offers tighter VBR control and lower VC for enhanced system-level margin, while SMBJ24 trades smaller footprint for greater thermal endurance - neither is pin-compatible due to differing package outlines, requiring layout revision.
Availability
SMAJ24 is available at Aetrix Electronics and suitable for industrial power adapters, automotive body control modules, and on-board DC/DC converters requiring stable component supply, consistent surge performance, and RoHS-compliant sourcing.
Supply support for SMAJ24 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, surface-mount transient suppression in automotive, industrial, and consumer power systems - emphasizing fast response, low leakage, and AEC-Q200-aligned robustness.
FAQ
What is the maximum clamping voltage of the SMAJ24 under standard surge conditions?
The SMAJ24 exhibits a maximum clamping voltage (VC) of 43.0 V when subjected to a 10/1000 µs waveform at its rated peak impulse current of 9.3 A. This value is measured per JEDEC standards and confirmed in Taiwan Semiconductor's U2102 datasheet. The SMAJ24 maintains this clamping performance across its full operating temperature range (-55°C to +150°C), making it suitable for harsh-environment applications where voltage excursions must remain tightly bounded.
Is the SMAJ24 unidirectional or bidirectional, and how is polarity marked?
The SMAJ24 is a unidirectional TVS diode, intended for DC rail protection with defined anode-to-cathode orientation. Polarity is marked on the DO-214AC (SMA) package via a distinct cathode band - the banded end connects to system ground or the low-side reference. This configuration ensures proper conduction only during reverse-biased transients, unlike bidirectional variants (e.g., SMAJ24C) which lack polarity marking and conduct symmetrically.
Does the SMAJ24 meet automotive surge immunity standards?
Yes, the SMAJ24 meets ISO 7637-2 requirements for Pulses 1, 2a, 2b, 3a, and 3b - covering common automotive transient threats including supply disconnection, inductive load switching, and capacitive coupling. Its 400 W peak pulse power rating, sub-1 ps response, and validated clamping behavior make it appropriate for use in body control modules, infotainment power supplies, and other 12/24 V vehicle subsystems per AEC-Q200 stress testing guidelines.
What is the reverse leakage current specification for the SMAJ24 at its working voltage?
The SMAJ24 specifies a maximum reverse leakage current (IR) of 1 µA when biased at its rated working stand-off voltage (VWM) of 24 V. This measurement is taken at 25°C ambient and confirms minimal standby power loss - critical for battery-powered or energy-efficient designs. Leakage remains well below 1 µA across industrial temperature ranges, supporting reliable operation in always-on monitoring circuits without compromising system quiescent current budgets.
Can the SMAJ24 be used in place of the SMAJ24A, and what are the trade-offs?
The SMAJ24 and SMAJ24A are not interchangeable without design review: SMAJ24A has a narrower breakdown voltage range (26.7–29.5 V vs. 26.7–32.6 V) and lower clamping voltage (38.9 V vs. 43.0 V). While both share identical VWM and package, the SMAJ24A's tighter VBR improves predictability in precision-clamp applications. Substituting SMAJ24 for SMAJ24A may increase worst-case clamping stress; using SMAJ24A in place of SMAJ24 requires verifying that lower VC does not cause unintended conduction during normal operation.
SMAJ24 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:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMAJ24 FAQ
1.How can I place an order for SMAJ24 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ24 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 SMAJ24 reliable?
The price and inventory of SMAJ24 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ24 is usually 5 days.
3.What payment methods are accepted for SMAJ24?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ24 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ24?
SMAJ24 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ24 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 SMAJ24?
For technical support, including SMAJ24 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ24 requirements.
6.How does Aetrix verify that SMAJ24 is sourced from the original manufacturer or authorized distributors?
All SMAJ24 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 SMAJ24 meets industry standards.
7.What is the process for return or replacement of SMAJ24?
All SMAJ24 units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ24, 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 SMAJ24 part is unused and in its original packaging.
Return procedure for SMAJ24:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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