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Taiwan Semiconductor Corporation SMAJ51CA
- Part No.:
- SMAJ51CA
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ51CA.pdf
- Description:
- TVS DIODE 51VWM 82.4VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:3,811
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Product details
Overview
SMAJ51CA from Taiwan Semiconductor is a bidirectional surface-mount transient voltage suppressor (TVS) diode in DO-214AC (SMA) package, designed for clamping fast transients in DC power lines and signal paths. It features a 51 V working stand-off voltage (VWM), 56.7–69.3 V breakdown voltage (VBR) at 1 mA test current, 91.1 V maximum clamping voltage (VC) at 4.4 A peak impulse current (IPPM), and 400 W peak pulse power rating with 10/1000 µs waveform.
For engineers reviewing the SMAJ51CA datasheet, SMAJ51CA pinout, SMAJ51CA application, or SMAJ51CA equivalent, key selection criteria include clamping performance under ISO 7637-2 Pulse 1/2a/2b/3a/3b, bidirectional surge protection capability, low leakage (<1 µA at VWM), and compatibility with automated SMT placement on industrial power supplies and automotive ECUs.
Technical Context
The SMAJ51CA operates as a silicon avalanche diode with glass-passivated junction, delivering sub-1 ps response time from 0 V to VBR min. Its bidirectional configuration enables symmetrical clamping in AC-coupled or floating circuits without polarity constraints.
It sustains 400 W peak pulse power per 10/1000 µs waveform up to TJ = 150 °C, with derating above 25 °C per Fig.2. The device meets JESD201 Class 2 whisker resistance and UL 94V-0 flammability requirements for high-reliability PCB mounting.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 51 V - Maximum continuous reverse operating voltage before significant leakage; defines safe DC bias margin. |
| VBR min/max | 56.7 V / 69.3 V at IT = 1 mA - Ensures reliable avalanche initiation across process variation and temperature. |
| VC @ IPPM | 91.1 V at 4.4 A - Clamped voltage during worst-case 10/1000 µs surge; determines protected circuit's overvoltage ceiling. |
| PPPM | 400 W (10/1000 µs) - Peak transient energy absorption capacity; supports robust immunity to load dump and inductive switching events. |
| IR @ VWM | <1 µA - Minimal standby power loss and negligible impact on high-impedance sensing or battery-backed circuits. |
| TJ max | +150 °C - Enables operation in under-hood automotive environments and enclosed industrial enclosures. |
| Package | DO-214AC (SMA) - Standardized surface-mount outline with 0.060 g mass; compatible with JEDEC MS-013 and IPC-7351B footprints. |
Pinout & Package
DO-214AC (SMA) package: molded plastic case with cathode band marking; matte tin-plated leads compliant with J-STD-002 solderability; polarity indicated by band (bidirectional operation means band denotes common reference, not unidirectional anode/cathode).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode/Cathode (symmetrical) | Bidirectional avalanche junction terminals | No functional polarity; either terminal serves as clamping node-enables placement flexibility in differential or floating lines. |
| Cathode band (marking) | Manufacturing orientation indicator | Not electrically functional in bidirectional mode; used only for visual alignment during placement and inspection. |
Key Features
| Feature | Design Value |
|---|---|
| Glass-passivated junction | Ensures stable VBR and low IR over lifetime; prevents moisture-induced parameter drift in humid environments. |
| <1 ps response time | Clamps ESD and fast transients before downstream ICs experience overstress-critical for USB, CAN, and sensor interfaces. |
| ISO 7637-2 compliance (Pulse 1/2a/2b/3a/3b) | Validated for automotive power line immunity; eliminates need for additional filtering in 12 V/24 V vehicle subsystems. |
| Moisture sensitivity level 1 (J-STD-020) | Zero bake requirement before reflow; reduces manufacturing cost and avoids thermal stress on adjacent components. |
| Halogen-free & RoHS compliant | Meets IEC 61249-2-21 and EU Directive 2011/65/EU; supports green manufacturing and end-of-life recycling mandates. |
Applications
| Automotive Body Control Module (BCM) | Industrial PLC Digital Input Card |
|---|---|
Use Scenario: Protects microcontroller GPIO and LIN bus transceivers from load dump and jump-start surges on 12 V supply rails. IC Role / Device Role / Timing Role: Bidirectional clamping TVS placed at power entry point before LDO regulator input. Use Value: Limits transient voltage to ≤91.1 V, preventing latch-up or gate oxide damage in 3.3 V/5 V logic ICs downstream. |
Use Scenario: Shields optocoupler inputs and FPGA I/O banks from field-wiring induced surges in factory automation cabinets. IC Role / Device Role / Timing Role: Primary overvoltage clamp on 24 V DC sensor input channel, upstream of series current-limiting resistor. Use Value: Absorbs 400 W pulses without degradation, maintaining signal integrity during maintenance hot-swap events. |
| LED Driver Power Stage | On-board DC/DC Converter Input |
Use Scenario: Guards MOSFET gate drivers and current-sense amplifiers against inductive kickback from LED string switching. IC Role / Device Role / Timing Role: Fast-response TVS across high-side switch drain-source path to suppress ringing and overshoot. Use Value: Sub-1 ps turn-on ensures clamping occurs within first 10 ns of transient onset-prevents false triggering of protection circuits. |
Use Scenario: Safeguards buck controller ICs and bootstrap capacitors from voltage spikes generated by long input traces in compact power modules. IC Role / Device Role / Timing Role: Secondary protection stage after bulk capacitor, placed directly at converter IC VIN pin. Use Value: 51 V VWM matches typical 48 V nominal input range, allowing full utilization of converter's input voltage headroom. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Littelfuse SMAJ51CA | Identical electrical specs, same DO-214AC package, identical marking and RoHS/halogen-free status; minor differences in tape-and-reel packaging quantity (7,500 vs. 8,000). | No functional difference; validated for same ISO 7637-2 pulses and automotive temperature range. | Drop-in replacement with no layout or qualification change required. |
| ON Semiconductor 1.5SMC51CA | Same VWM (51 V), but higher VC (93.6 V at 4.3 A), lower PPPM (1500 W rated but derated to 400 W at 10/1000 µs), larger DO-214AB (SMB) package (3.56 mm × 4.57 mm vs. SMA's 2.92 mm × 4.45 mm). | Requires PCB footprint revision; suitable where higher surge margin is needed but board space allows SMB size. | Consider only when higher peak current handling (>4.4 A) is required and layout can accommodate larger body. |
Compared with Littelfuse SMAJ51CA, Taiwan Semiconductor SMAJ51CA offers identical performance and fit; versus ON Semi 1.5SMC51CA, it delivers equivalent clamping at lower profile and tighter board area-critical for space-constrained DC/DC modules and automotive sensors.
Availability
SMAJ51CA is available at Aetrix Electronics and suitable for automotive electronics, industrial power supplies, and LED lighting systems requiring stable component supply with full traceability and lifecycle continuity.
Supply support for SMAJ51CA 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 since 1979.
The SMAJ series was developed specifically for high-reliability transient suppression in automotive and industrial environments, emphasizing fast response, low leakage, and robust package reliability under thermal cycling and humidity stress.
FAQ
What is the clamping voltage of SMAJ51CA under standard 10/1000 µs surge conditions?
The SMAJ51CA exhibits a maximum clamping voltage (VC) of 91.1 V when subjected to its rated peak impulse current of 4.4 A using the 10/1000 µs waveform. This value is measured per IEC 61000-4-5 and confirmed in Taiwan Semiconductor's U2102 datasheet, ensuring predictable overvoltage limiting for downstream 5 V or 3.3 V logic circuits protected by SMAJ51CA.
Is SMAJ51CA unidirectional or bidirectional, and how does that affect circuit placement?
SMAJ51CA is a bidirectional TVS diode, indicated by the "CA" suffix per Taiwan Semiconductor's naming convention. It provides symmetrical clamping in both polarities, eliminating the need to observe orientation during placement-unlike unidirectional "A" variants. This makes SMAJ51CA ideal for AC-coupled lines, floating grounds, or differential buses where polarity reversal may occur.
Does SMAJ51CA meet automotive-grade reliability standards such as AEC-Q200?
Taiwan Semiconductor does not list SMAJ51CA as AEC-Q200 qualified in the U2102 datasheet. However, it meets ISO 7637-2 Pulse 1/2a/2b/3a/3b for automotive power line immunity and is rated for −55 °C to +150 °C operating junction temperature-key requirements for under-hood use. For AEC-Q200 certification, consult TSC's qualified product list or request test reports separately.
What is the maximum steady-state power dissipation (PD) for SMAJ51CA?
The SMAJ51CA has a maximum steady-state power dissipation (PD) of 1 W at TA = 25 °C, as specified in the Absolute Maximum Ratings table. This rating applies to continuous DC reverse bias conditions-not transient events-and must be derated linearly above 25 °C ambient per the pulse derating curve (Fig.2) to avoid thermal runaway or parametric shift.
Can SMAJ51CA be used in place of SMAJ51A, and what is the key difference?
No-SMAJ51CA and SMAJ51A are not interchangeable. SMAJ51CA is bidirectional (clamps in both directions), while SMAJ51A is unidirectional (clamps only in reverse bias). Substituting SMAJ51A for SMAJ51CA would leave the forward-polarity transient unprotected. Always verify suffix: "CA" = bidirectional, "A" = unidirectional. Both share same VWM (51 V) and package (DO-214AC), but differ fundamentally in conduction symmetry.
SMAJ51CA 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:
- -
- Bidirectional Channels:
- 1
- Voltage - Reverse Standoff (Typ):
- 51V
- Voltage - Breakdown (Min):
- 56.7V
- Voltage - Clamping (Max) @ Ipp:
- 82.4V
- Current - Peak Pulse (10/1000µs):
- 4.9A
- 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)
SMAJ51CA FAQ
1.How can I place an order for SMAJ51CA through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ51CA 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 SMAJ51CA reliable?
The price and inventory of SMAJ51CA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ51CA is usually 5 days.
3.What payment methods are accepted for SMAJ51CA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ51CA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ51CA?
SMAJ51CA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ51CA 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 SMAJ51CA?
For technical support, including SMAJ51CA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ51CA requirements.
6.How does Aetrix verify that SMAJ51CA is sourced from the original manufacturer or authorized distributors?
All SMAJ51CA 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 SMAJ51CA meets industry standards.
7.What is the process for return or replacement of SMAJ51CA?
All SMAJ51CA units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ51CA, 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 SMAJ51CA part is unused and in its original packaging.
Return procedure for SMAJ51CA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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