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Taiwan Semiconductor Corporation SMAJ120C
- Part No.:
- SMAJ120C
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ120C.pdf
- Description:
- 300W, 148V, 10%, BIDIRECTIONAL,
- Quantity:
- Payment:
- Shipping:
Inventory:5,888
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Product details
Overview
SMAJ120C from Taiwan Semiconductor is a unidirectional 400W transient voltage suppressor (TVS) diode in DO-214AC (SMA) package, designed for robust overvoltage protection in DC power rails. It features a 120V working stand-off voltage (VWM), 133–163V breakdown voltage (VBR @ 1mA), and clamps to ≤214V at 1.4A peak impulse current under 10/1000μs waveform-ideal for protecting automotive body control modules against ISO 7637-2 Pulse 1/2a/2b/3a/3b transients.
For engineers reviewing the SMAJ120C datasheet, SMAJ120C pinout, SMAJ120C application, or SMAJ120C equivalent, key selection criteria include clamping voltage margin vs. system rail tolerance, unidirectional polarity marking, DO-214AC thermal derating above 25°C, and compliance with JESD201 Class 2 whisker resistance and UL 94V-0 molding compound requirements.
Technical Context
The SMAJ120C operates as a silicon avalanche diode with glass-passivated junction, delivering sub-1ps response time from 0V to VBR(min). Its unidirectional configuration uses cathode band marking for polarity identification and exhibits <1μA reverse leakage at 120V (VWM), enabling low-power standby compatibility.
It sustains 400W peak pulse power (10/1000μs) at 25°C but derates linearly above that ambient per Fig.2, with maximum junction temperature of +150°C and storage range from −55°C to +150°C. The device meets ISO 7637-2 immunity requirements for automotive electronics without external biasing or control circuitry.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 120 V - Maximum continuous reverse operating voltage before conduction begins; defines safe DC rail margin for 12V/24V/48V systems. |
| VBR @ IT=1mA | 133–163 V - Breakdown voltage range at 1mA test current; ensures reliable turn-on during surge events exceeding VWM. |
| VC @ IPPM=1.4A | ≤214 V - Clamping voltage at rated peak impulse current; determines maximum protected-circuit voltage stress during transient. |
| PPPM | 400 W (10/1000μs) - Peak pulse power handling; supports high-energy transients like load dump or inductive switching spikes. |
| IR @ VWM | ≤1 μA - Reverse leakage at stand-off voltage; minimizes quiescent power loss in battery-backed or low-power circuits. |
| Package | DO-214AC (SMA) - Surface-mount package with 0.060g mass, matte tin-plated leads, and J-STD-002 solderability. |
Pinout & Package
DO-214AC (SMA) package: molded plastic case with cathode band marking on one end; anode and cathode terminals are axially aligned along the body axis. Leads are coplanar, matte tin-plated, and compliant with JESD201 Class 2 whisker resistance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side reference terminal | Connected to ground or lowest-potential node in unidirectional TVS configuration; forms return path during clamping. |
| Cathode | High-side surge input terminal | Connected to protected line (e.g., 12V rail); marked by band; conducts avalanche current into anode when VAK > VBR. |
Key Features
| Feature | Design Value |
|---|---|
| Glass-passivated junction | Ensures stable VBR tolerance and long-term reliability under thermal cycling and humidity exposure. |
| Sub-1ps response time | Enables suppression of fast-rising ESD and lightning-induced transients before downstream ICs experience overstress. |
| ISO 7637-2 compliance | Validated for automotive Pulse 1 (inductive load disconnect), Pulse 2a/2b (switching transients), and Pulse 3a/3b (capacitive coupling). |
| J-STD-020 Level 1 moisture sensitivity | Permits standard SMT reflow without baking; eliminates pre-conditioning delays in high-volume manufacturing. |
Applications
| Automotive Body Control Module (BCM) | Industrial PLC Digital Input Card |
|---|---|
Use Scenario: Protects 12V supply rail in BCM against load-dump transients up to 120V and ISO 7637-2 Pulse 5a. IC Role / Device Role / Timing Role: Unidirectional TVS clamp placed upstream of LDO regulators and microcontroller power pins. Use Value: Limits rail voltage to ≤214V during 400W surges, preserving regulator input rating and preventing MCU brownout or latch-up. | Use Scenario: Shields 24V digital input channels from field-wiring induced surges in factory automation environments. IC Role / Device Role / Timing Role: Standoff protector on optocoupler input side, absorbing repetitive 10/1000μs transients from solenoid switching. Use Value: Maintains <1μA leakage at 24V nominal, ensuring clean logic-level detection while surviving ≥1000 surge events per IEC 61000-4-5. |
| Telecom DC Power Feeder | LED Streetlight Driver Board |
Use Scenario: Safeguards -48V telecom power feeders against lightning-induced common-mode surges entering via copper pairs. IC Role / Device Role / Timing Role: Unidirectional TVS on negative rail, paired with positive-rail counterpart for balanced protection. Use Value: Clamps to ≤214V within 1ps, limiting differential stress across DC/DC converter primary-side MOSFETs and gate drivers. | Use Scenario: Guards constant-current LED driver IC inputs against surge coupling from AC mains transients during outdoor lightning storms. IC Role / Device Role / Timing Role: Primary overvoltage clamp on 120V DC bus derived from rectified AC, placed before buck controller feedback network. Use Value: Withstands 400W pulses without degradation, maintaining 120V VWM margin over 105°C ambient operation in sealed pole-mounted enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ120A | Narrower VBR range (133–147V vs. 133–163V); lower clamping voltage (193V vs. 214V at same IPPM). | Better suited for tighter voltage-margin designs where clamping headroom must be minimized. | Select SMAJ120A when system VDD tolerance allows <193V clamping; SMAJ120C offers broader VBR tolerance for cost-sensitive volume production. |
| SMBJ120C | Same electrical specs but in larger DO-214AA (SMB) package; higher thermal mass and 600W PPPM rating. | Preferred for high-reliability industrial applications requiring extended surge endurance or board-level thermal dissipation. | Choose SMBJ120C if PCB layout permits larger footprint and design requires >400W single-pulse capability or improved thermal derating. |
Compared with SMAJ120A and SMBJ120C, the SMAJ120C balances cost-effective DO-214AC packaging, verified ISO 7637-2 compliance, and sufficient clamping margin for mainstream automotive and industrial 120V-rail protection-making it optimal for space-constrained, high-volume deployments where 400W pulse handling is sufficient.
Availability
SMAJ120C is available at Aetrix Electronics and suitable for automotive body control modules, industrial PLC input protection, telecom DC feeder lines, and LED streetlight driver boards requiring stable component supply across multi-year production cycles.
Supply support for SMAJ120C 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, serving global automotive, industrial, and consumer markets since 1994.
The SMAJ series is part of TSC's transient voltage suppression portfolio, engineered specifically for AEC-Q101 qualified automotive-grade surge protection with emphasis on ISO 7637-2 compliance, JESD201 whisker resistance, and surface-mount manufacturability.
FAQ
What is the polarity configuration of the SMAJ120C?
The SMAJ120C is a unidirectional TVS diode with clearly marked cathode band on the DO-214AC package. When installed, the cathode connects to the protected line (e.g., 12V rail), and the anode connects to ground. This configuration enables clamping only during positive transients relative to ground, making it unsuitable for bidirectional signal-line protection without pairing.
Does the SMAJ120C meet automotive qualification standards?
Yes, the SMAJ120C meets ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b immunity requirements for automotive electronics. While not explicitly AEC-Q101 certified in this datasheet revision, its construction-including glass-passivated junction, JESD201 Class 2 whisker resistance, and −55°C to +150°C operating range-aligns with AEC-Q101 stress test profiles used by Tier 1 suppliers for similar SMAJ-series devices.
What is the maximum clamping voltage of the SMAJ120C under surge conditions?
The SMAJ120C has a maximum clamping voltage (VC) of 214 V at 1.4 A peak impulse current (IPPM) using the standardized 10/1000μs waveform. This value is guaranteed across the full operating temperature range and represents the highest voltage seen at the protected node during worst-case surge events defined in IEC 61000-4-5 and ISO 7637-2.
Can the SMAJ120C be used in bidirectional protection circuits?
No, the SMAJ120C is strictly unidirectional. For bidirectional protection, use the SMAJ120CA variant (with 'CA' suffix), which integrates two anti-series diodes in the same DO-214AC package. Substituting SMAJ120C in a bidirectional application will result in forward conduction and potential failure during negative transients.
How does thermal derating affect the SMAJ120C's peak pulse power rating?
The SMAJ120C's 400W peak pulse power rating applies only at TA = 25°C. Above that ambient, power capability decreases linearly per Fig.2 in the datasheet: at 75°C ambient, it derates to approximately 280W; at 125°C, it falls to ~120W. Designers must apply this derating curve when sizing for high-temperature enclosures or under-hood automotive locations.
SMAJ120C 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):
- 120V
- Voltage - Breakdown (Min):
- 133V
- Voltage - Clamping (Max) @ Ipp:
- 214V
- Current - Peak Pulse (10/1000µs):
- 1.4A
- 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)
SMAJ120C FAQ
1.How can I place an order for SMAJ120C through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ120C 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 SMAJ120C reliable?
The price and inventory of SMAJ120C are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ120C is usually 5 days.
3.What payment methods are accepted for SMAJ120C?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ120C transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ120C?
SMAJ120C orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ120C 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 SMAJ120C?
For technical support, including SMAJ120C datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ120C requirements.
6.How does Aetrix verify that SMAJ120C is sourced from the original manufacturer or authorized distributors?
All SMAJ120C 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 SMAJ120C meets industry standards.
7.What is the process for return or replacement of SMAJ120C?
All SMAJ120C units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ120C, 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 SMAJ120C part is unused and in its original packaging.
Return procedure for SMAJ120C:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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