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Taiwan Semiconductor Corporation SMAJ33C
- Part No.:
- SMAJ33C
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ33C.pdf
- Description:
- 400W, 40.8V, 10%, BIDIRECTIONAL,
- Quantity:
- Payment:
- Shipping:
Inventory:6,166
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Product details
Overview
SMAJ33C from Taiwan Semiconductor is a unidirectional 400W transient voltage suppressor (TVS) diode in DO-214AC (SMA) package, designed for overvoltage protection of DC power rails and signal lines. It features a 33V working stand-off voltage (VWM), 36.7–44.9V breakdown voltage (VBR) at 1mA test current, and clamps to ≤59.0V at 6.8A peak impulse current under 10/1000μs waveform - used in automotive DC/DC converters and industrial SMPS inputs.
For engineers reviewing the SMAJ33C datasheet, SMAJ33C pinout, SMAJ33C application, or SMAJ33C equivalent, key selection criteria include clamping voltage margin relative to protected IC VDD, leakage current (<1μA @ 33V), junction temperature rating (−55°C to +150°C), and ISO 7637-2 Pulse 1/2a/2b/3a/3b compliance for automotive transients.
Technical Context
The SMAJ33C operates as a unidirectional avalanche diode with glass-passivated junction, delivering sub-1ps response time from 0V to VBR min. Its clamping behavior follows standardized 10/1000μs surge waveform per IEC 61000-4-5 and meets ISO 7637-2 for automotive load-dump and inductive-switching immunity.
It is rated for 400W peak pulse power at TA = 25°C (derated linearly above), 1W steady-state dissipation, and withstands 40A non-repetitive forward surge (8.3ms half-sine). Polarity is marked by cathode band; terminals are matte tin-plated for J-STD-002 solderability.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 33 V - Maximum continuous reverse operating voltage before conduction begins; sets upper limit for protected circuit's nominal rail. |
| VBR min/max | 36.7 V / 44.9 V @ 1 mA - Ensures reliable turn-on above system overvoltage threshold while avoiding false triggering. |
| VC @ IPPM | ≤59.0 V @ 6.8 A - Clamping voltage during 10/1000μs surge; defines maximum stress seen by downstream ICs. |
| IR @ VWM | ≤1 μA - Negligible leakage at operating voltage, critical for low-power standby circuits. |
| PPPM | 400 W (10/1000μs) - Peak surge energy handling capacity; sufficient for ISO 7637-2 Pulse 1 (−150V/0.5Ω) and Pulse 2b (−100V/2Ω). |
| TJ max | +150 °C - Enables use in under-hood automotive environments and high-ambient industrial enclosures. |
| Package | DO-214AC (SMA) - Surface-mount footprint compatible with automated placement; 0.060g mass supports thermal cycling reliability. |
Pinout & Package
DO-214AC (SMA) package: molded epoxy case meeting UL 94V-0, matte tin-plated leads, cathode indicated by band on body. Weight ≈0.060g. Moisture sensitivity level (MSL) = 1 per J-STD-020.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal | Connected to lower-potential side (e.g., GND or return path); conducts during positive surges when used in reverse-biased configuration. |
| Cathode | Reverse-bias conduction terminal | Connected to protected line (e.g., +33V rail); avalanche conduction occurs here during overvoltage events. |
Key Features
| Feature | Design Value |
|---|---|
| Fast response time | <1.0 ps from 0 V to VBR min - Ensures suppression initiates before sensitive ICs experience damaging voltage overshoot. |
| Clamping performance | VC/VBR ratio ≤1.61 - Low clamping-to-breakdown ratio improves margin for 3.3V/5V logic interfaces. |
| Automated placement compatibility | DO-214AC tape-and-reel packaging (7,500 pcs/reel) - Supports high-volume SMT assembly without manual handling. |
| Environmental compliance | RoHS-compliant and halogen-free per IEC 61249-2-21 - Meets global environmental regulations for automotive and industrial end equipment. |
| Transient immunity | Meets ISO 7637-2 Pulse 1/2a/2b/3a/3b - Validated for automotive battery-line transients including load dump and inductive switching noise. |
Applications
| Automotive DC/DC Converter Input Protection | Industrial SMPS Line Surge Suppression |
|---|---|
Use Scenario: Protects 3.3V/5V buck converter input stage against load-dump transients (ISO 7637-2 Pulse 5a) and alternator ripple in 12V/24V vehicle systems. IC Role / Device Role / Timing Role: Unidirectional TVS placed between VIN and GND, clamping surges before they reach controller IC and MOSFET gate drivers. Use Value: Limits peak voltage to ≤59.0V, preserving integrity of 60V-rated input capacitors and enabling use of cost-optimized 40V-input controllers. |
Use Scenario: Shields primary-side rectifier and PWM controller in 100–500W industrial switch-mode power supplies from lightning-induced surges and AC line switching spikes. IC Role / Device Role / Timing Role: Parallel-connected TVS across bulk capacitor input, absorbing 400W 10/1000μs pulses without degradation over >10,000 cycles. Use Value: Eliminates need for series impedance or varistor-based solutions requiring derating, reducing BOM count and board space. |
| LED Driver Power Rail Protection | On-Board CAN Transceiver ESD/Transient Guard |
Use Scenario: Safeguards constant-current LED driver ICs in streetlight and signage applications exposed to outdoor lightning coupling and hot-plug events. IC Role / Device Role / Timing Role: Mounted directly at driver IC supply pins to suppress fast-rising transients (e.g., EFT bursts) before internal LDOs or gate drivers fail. Use Value: Sub-1ps response ensures clamping activation within first 10ns of surge onset, preventing latch-up in CMOS-based LED controllers. |
Use Scenario: Provides secondary-level protection for CAN FD transceivers (e.g., TCAN1042) in vehicle ECUs subjected to ISO 10605 ESD and ISO 7637-2 Pulse 2a (inductive kick). IC Role / Device Role / Timing Role: Placed between CAN_H/CAN_L lines and ground, operating bidirectionally when paired with SMAJ33CA variant; SMAJ33C used for single-line GND-referenced suppression. Use Value: 1μA leakage at 33V prevents bus bias shift, maintaining CAN common-mode range while surviving ≥30kV contact ESD per IEC 61000-4-2. |
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 SMAJ33A | VBR = 36.7–40.6V (tighter tolerance), VC = 53.3V @ 7.5A - lower clamping voltage but reduced surge current rating. | Better for low-voltage-margin designs where <55V clamping is mandatory; less suitable for high-impedance source transients requiring >6.8A IPPM. | Select SMAJ33A if clamping voltage headroom is constrained; verify layout thermal relief matches 38.9W derated power at 85°C ambient. |
| ON Semiconductor SMAJ33CA | Bidirectional version (VRWM = ±33V), same VBR/VC specs - enables symmetric suppression on differential buses like RS-485 or CAN. | Required for differential-line protection; not interchangeable with SMAJ33C in unidirectional GND-referenced configurations without circuit redesign. | Choose SMAJ33CA only when protecting balanced signaling pairs; SMAJ33C remains optimal for single-rail DC protection. |
Compared with SMAJ33A and SMAJ33CA, the SMAJ33C offers the highest peak impulse current (6.8A) among 33V unidirectional SMA devices, making it preferred for high-energy automotive load-dump scenarios where clamping voltage margin allows up to 59.0V, while SMAJ33A trades current capacity for tighter clamping and SMAJ33CA adds bidirectional symmetry at the cost of polarity-specific layout flexibility.
Availability
SMAJ33C 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 SMAJ33C 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 components.
The SMAJ series was developed specifically for robust, surface-mount transient suppression in automotive and industrial environments, emphasizing ISO 7637-2 compliance, high-temperature reliability, and automated assembly readiness.
FAQ
What is the polarity configuration of SMAJ33C?
The SMAJ33C is a unidirectional transient voltage suppressor diode, with cathode marked by a band on the DO-214AC (SMA) package body. It conducts in reverse bias during overvoltage events and blocks forward current up to 3.5V at 25A. This configuration makes SMAJ33C suitable for GND-referenced DC rail protection, unlike bidirectional variants such as SMAJ33CA.
Does SMAJ33C meet automotive transient standards?
Yes, SMAJ33C meets ISO 7637-2 requirements for Pulse 1 (inductive load disconnect), Pulse 2a (sudden load removal), Pulse 2b (supply interruption), and Pulse 3a/3b (switching noise), verified per manufacturer test data. Its 400W 10/1000μs rating and −55°C to +150°C operating range align with AEC-Q101 stress testing profiles for automotive-grade discretes.
What is the maximum clamping voltage of SMAJ33C under surge conditions?
The maximum clamping voltage (VC) of SMAJ33C is 59.0 V at 6.8 A peak impulse current (IPPM) under the standardized 10/1000μs waveform. This value is guaranteed across the full operating temperature range and forms the basis for downstream IC voltage stress analysis in designs using SMAJ33C.
Can SMAJ33C be used in bidirectional signal line protection?
No - SMAJ33C is unidirectional and must be used with correct polarity (cathode to protected line). For bidirectional protection of differential buses like CAN or RS-485, the SMAJ33CA variant is required. Using SMAJ33C on bidirectional lines risks forward conduction during normal signal swings and failure to suppress negative transients.
What is the leakage current specification for SMAJ33C at its working voltage?
SMAJ33C exhibits a maximum reverse leakage current (IR) of 1 μA at its working stand-off voltage (VWM) of 33 V and TA = 25°C. This ultra-low leakage ensures minimal power loss in always-on systems and avoids interference with precision voltage monitoring circuits upstream of the protected rail.
SMAJ33C 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):
- 33V
- Voltage - Breakdown (Min):
- 36.7V
- Voltage - Clamping (Max) @ Ipp:
- 59V
- Current - Peak Pulse (10/1000µs):
- 6.8A
- 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)
SMAJ33C FAQ
1.How can I place an order for SMAJ33C through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ33C 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 SMAJ33C reliable?
The price and inventory of SMAJ33C are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ33C is usually 5 days.
3.What payment methods are accepted for SMAJ33C?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ33C transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ33C?
SMAJ33C orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ33C 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 SMAJ33C?
For technical support, including SMAJ33C datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ33C requirements.
6.How does Aetrix verify that SMAJ33C is sourced from the original manufacturer or authorized distributors?
All SMAJ33C 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 SMAJ33C meets industry standards.
7.What is the process for return or replacement of SMAJ33C?
All SMAJ33C units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ33C, 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 SMAJ33C part is unused and in its original packaging.
Return procedure for SMAJ33C:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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