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Taiwan Semiconductor Corporation SMAJ120AH
- Part No.:
- SMAJ120AH
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ120AH.pdf
- Description:
- TVS DIODE 120VWM 193VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:9,741
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Product details
Overview
SMAJ120AH from Taiwan Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode designed for robust overvoltage protection in DC power rails and signal lines. It features a 120 V working stand-off voltage (VWM), 133–147 V breakdown voltage (VBR), 193 V maximum clamping voltage (VC) at 1.6 A peak impulse current, and 400 W peak pulse power (10/1000 µs waveform). It is widely deployed in automotive-grade DC/DC converters and industrial SMPS inputs.
For engineers reviewing the SMAJ120AH datasheet, SMAJ120AH pinout, SMAJ120AH application, or SMAJ120AH equivalent, key selection criteria include its AEC-Q101 qualification, DO-214AC (SMA) package compatibility with automated placement, sub-1 ps response time, <1 µA leakage above 10 V, and ISO 7637-2 Pulse 1/2a/2b/3a/3b compliance for automotive transients.
Technical Context
The SMAJ120AH operates as a unidirectional avalanche diode, leveraging glass-passivated junction technology to achieve fast transient suppression with minimal capacitance. Its clamping behavior is defined by a tightly controlled VBR range (133–147 V at 1 mA test current) and low dynamic impedance, ensuring predictable voltage limiting during ESD or load-dump events.
It is rated for 150 °C maximum junction temperature and supports bidirectional variants via CH/CAH suffixes - though SMAJ120AH itself is unidirectional, with cathode polarity marked on the DO-214AC case. Its 1.6 A peak impulse current (IPPM) corresponds to a 10/1000 µs waveform and is derated linearly above 25 °C ambient per the manufacturer's pulse derating curve.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 120 V - Maximum continuous DC or RMS voltage the device blocks without conduction |
| VBR @ IT=1 mA | 133–147 V - Breakdown initiates within this range, defining turn-on threshold under standardized test conditions |
| VC @ IPPM=1.6 A | 193 V - Maximum clamped voltage seen across terminals during 10/1000 µs surge, limiting downstream stress |
| PPPM | 400 W - Peak pulse power handling capability for non-repetitive 10/1000 µs transients (300 W above 78 V) |
| IR @ VWM | <1 µA - Extremely low reverse leakage ensures minimal standby power loss and signal integrity in high-impedance circuits |
| Response Time | <1.0 ps - Sub-picosecond junction response enables effective suppression of fast-rising ESD and switching noise |
| TJ max | 150 °C - Enables reliable operation in under-hood automotive and high-temperature industrial environments |
Pinout & Package
Package: DO-214AC (SMA), surface-mount, single-diode configuration with molded epoxy case meeting UL 94V-0 flammability rating. Matte tin-plated leads comply with J-STD-002 solderability and JESD 201 Class 2 whisker resistance. Polarity indicated by cathode band.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Input/Line side (non-marked end) | Connected to protected line; conducts during reverse-biased overvoltage events |
| Cathode | Ground/Reference side (marked end) | Connected to system ground or low-impedance return; defines unidirectional clamping direction |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive applications including temperature cycling, humidity bias, and mechanical shock per stress test requirements |
| Glass passivated junction | Enhances long-term reliability and stability of VBR and leakage under thermal and humidity stress |
| ISO 7637-2 compliance | Withstands Pulse 1 (inductive load dump), Pulse 2a/2b (switching transients), and Pulse 3a/3b (capacitive coupling) waveforms |
| Moisture sensitivity level 1 | No floor life limitation or bake requirement prior to reflow - compatible with standard SMT assembly processes |
| Halogen-free & RoHS compliant | Meets IEC 61249-2-21 and EU RoHS Directive 2011/65/EU for environmentally constrained designs |
Applications
| Automotive DC/DC Converters | Industrial SMPS Inputs |
|---|---|
Use Scenario: Protecting 12 V/24 V input stage of buck-based DC/DC modules against load dump and jump-start transients in vehicle ECUs. IC Role / Device Role / Timing Role: Unidirectional TVS diode placed between input rail and chassis ground to clamp surges before they reach controller ICs and MOSFETs. Use Value: Limits peak voltage to ≤193 V during 10/1000 µs pulses, preventing gate oxide damage and latch-up in downstream power stages. | Use Scenario: Safeguarding AC-DC front-end rectified outputs and isolated DC bus rails in factory automation power supplies. IC Role / Device Role / Timing Role: Standoff protector on +VOUT lines, absorbing repetitive switching spikes and lightning-induced surges on 48 V or 60 V distribution buses. Use Value: Delivers 400 W pulse power handling with <1 µA leakage, minimizing standby loss while maintaining tight VWM/VC margin. |
| LED Driver Power Stages | On-Board Charger (OBC) Auxiliary Rails |
Use Scenario: Overvoltage protection for constant-current LED driver ICs operating from 24–48 V supplies in streetlight and signage systems. IC Role / Device Role / Timing Role: Parallel-connected TVS on driver IC supply pins to shunt inductive kickback from LED string switching. Use Value: Sub-1 ps response ensures clamping occurs before driver IC internal ESD structures are stressed, extending lifetime in outdoor deployments. | Use Scenario: Input rail protection for auxiliary 12 V control logic in electric vehicle on-board chargers exposed to battery-side transients. IC Role / Device Role / Timing Role: Unidirectional suppressor between HV battery interface and isolated 12 V LDO input, referenced to functional ground. Use Value: AEC-Q101 qualification and ISO 7637-2 Pulse 1 support ensure compliance with automotive OEM requirements for OBC subsystems. |
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 | Same VWM, VBR, and VC specs; identical DO-214AC package; differs only in manufacturer (Littelfuse) and minor process variation | No functional difference in circuit design; validated in same automotive and industrial reference designs | Select SMAJ120A when dual-sourcing or qualifying alternate suppliers without layout change |
| P6SMB120A | Same 120 V VWM and DO-214AA (SMB) package; lower PPPM = 600 W (but derated to ~300 W above 78 V); slightly higher VC = 196 V | Larger SMB footprint requires PCB pad revision; suitable where higher surge margin is needed but space allows | Choose P6SMB120A only if board redesign accommodates larger package and higher clamping voltage is acceptable |
Compared with SMAJ120A and P6SMB120A, the SMAJ120AH offers identical electrical performance in a compact DO-214AC footprint, AEC-Q101 qualification out-of-box, and moisture sensitivity level 1 - making it optimal for high-volume automotive SMT lines where reliability, assembly yield, and qualification alignment are critical.
Availability
SMAJ120AH is available at Aetrix Electronics and suitable for automotive DC/DC converters, industrial SMPS inputs, and LED driver power stages requiring stable component supply, AEC-Q101 compliance, and ISO 7637-2 transient immunity.
Supply support for SMAJ120AH 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 automotive and industrial transient suppression, emphasizing AEC-Q101 qualification, tight parametric tolerances, and robust packaging for automated SMT deployment.
FAQ
What is the polarity configuration of the SMAJ120AH?
The SMAJ120AH is a unidirectional TVS diode with clearly marked cathode polarity (band) on the DO-214AC package. It conducts only when the anode is driven negative relative to the cathode - meaning it protects positive-going transients on lines referenced to ground. This configuration matches standard DC rail protection layouts and is distinct from bidirectional variants like SMAJ120CH.
Does the SMAJ120AH meet automotive qualification standards?
Yes, the SMAJ120AH is explicitly AEC-Q101 qualified per the manufacturer's datasheet (Version A2102). It has undergone stress testing for temperature cycling, high-temperature operating life, humidity bias, and mechanical shock - confirming suitability for under-hood and body-control module applications in passenger vehicles and commercial EVs.
What is the maximum clamping voltage of the SMAJ120AH under surge conditions?
The SMAJ120AH has a maximum clamping voltage (VC) of 193 V at 1.6 A peak impulse current (IPPM) using the standard 10/1000 µs waveform. This value is guaranteed across temperature and lot variations and defines the upper voltage limit imposed on protected circuitry during transient events.
Can the SMAJ120AH be used in bidirectional protection circuits?
No - the SMAJ120AH is unidirectional only. For bidirectional protection, Taiwan Semiconductor specifies the SMAJ120CH or SMAJ120CAH variants, which feature symmetrical breakdown in both directions. Using SMAJ120AH in a bidirectional configuration would result in forward conduction during negative transients, potentially damaging the device or failing to protect.
What is the moisture sensitivity level (MSL) rating for the SMAJ120AH?
The SMAJ120AH carries a moisture sensitivity level (MSL) rating of Level 1 per J-STD-020, meaning it has unlimited floor life and does not require dry-packaging or baking prior to reflow soldering. This simplifies manufacturing logistics and improves first-pass yield in high-speed SMT lines.
SMAJ120AH 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):
- 120V
- Voltage - Breakdown (Min):
- 133V
- Voltage - Clamping (Max) @ Ipp:
- 193V
- Current - Peak Pulse (10/1000µs):
- 1.6A
- Power - Peak Pulse:
- 400W
- Power Line Protection:
- No
- Applications:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMAJ120AH FAQ
1.How can I place an order for SMAJ120AH through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ120AH 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 SMAJ120AH reliable?
The price and inventory of SMAJ120AH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ120AH is usually 5 days.
3.What payment methods are accepted for SMAJ120AH?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ120AH transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ120AH?
SMAJ120AH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ120AH 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 SMAJ120AH?
For technical support, including SMAJ120AH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ120AH requirements.
6.How does Aetrix verify that SMAJ120AH is sourced from the original manufacturer or authorized distributors?
All SMAJ120AH 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 SMAJ120AH meets industry standards.
7.What is the process for return or replacement of SMAJ120AH?
All SMAJ120AH units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ120AH, 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 SMAJ120AH part is unused and in its original packaging.
Return procedure for SMAJ120AH:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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