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Taiwan Semiconductor Corporation SMAJ45CH
- Part No.:
- SMAJ45CH
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ45CH.pdf
- Description:
- TVS DIODE 45VWM 80.3VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:7,059
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Product details
Overview
SMAJ45CH from Taiwan Semiconductor is a unidirectional 400W surface-mount transient voltage suppressor (TVS) diode in DO-214AC (SMA) package, with 45V working stand-off voltage (VWM), 50.0–61.1V breakdown voltage (VBR), and 80.3V maximum clamping voltage (VC) at 5.0A peak impulse current. It delivers AEC-Q101 qualification and meets ISO 7637-2 Pulse 1/2a/2b/3a/3b for automotive power line protection.
For engineers reviewing the SMAJ45CH datasheet, SMAJ45CH pinout, SMAJ45CH application, or SMAJ45CH equivalent, key selection criteria include clamping performance under 10/1000μs surge, unidirectional polarity marking, DO-214AC thermal derating above 25°C, and compliance with automotive EMC transients and J-STD-020 level 1 moisture sensitivity.
Technical Context
The SMAJ45CH operates as a unidirectional avalanche diode, triggered when reverse voltage exceeds its VBR range (50.0–61.1V at 1mA test current). Its glass-passivated junction ensures stable breakdown and low leakage (<1μA at 45V), while fast response (<1.0ps) enables effective suppression of ESD and load-dump transients.
Designed for automotive-grade reliability, it supports junction temperatures from –55°C to +150°C, withstands 40A non-repetitive forward surge (8.3ms half-sine), and maintains 400W peak pulse power (10/1000μs) up to 78V - derated linearly beyond 25°C ambient per Fig.2.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 45 V - Maximum continuous reverse operating voltage before conduction begins |
| VBR min/max | 50.0 / 61.1 V @ 1 mA - Ensures reliable turn-on margin above system nominal rail |
| VC @ IPPM | 80.3 V @ 5.0 A - Clamped voltage during 10/1000μs surge limits downstream IC stress |
| PPPM | 400 W (10/1000μs) - Sustains automotive load-dump energy without failure |
| IR @ VWM | <1 μA - Negligible leakage preserves battery-powered circuit standby current |
| TJ max | +150 °C - Enables placement near hot components in engine control units |
| Package | DO-214AC (SMA) - Standardized footprint compatible with automated SMT assembly |
Pinout & Package
DO-214AC (SMA) package with cathode band marking on one end; two-terminal unidirectional configuration. Matte tin-plated leads meet J-STD-002 solderability requirements and JESD201 Class 2 whisker resistance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward current entry / Reverse surge return path | Connected to protected line (e.g., 45V supply rail); conducts during overvoltage |
| Cathode | Reverse-biased terminal / Clamping reference | Connected to ground or lower-potential rail; defines polarity and clamping threshold |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive under-hood applications including temperature cycling, humidity, and mechanical shock |
| Glass passivated junction | Stable VBR tolerance and long-term reliability under repeated surge stress |
| Fast response time <1.0 ps | Clamps ESD events before sensitive logic or analog circuits experience overstress |
| ISO 7637-2 compliance | Withstands standardized automotive transients (Pulse 1, 2a, 2b, 3a, 3b) without degradation |
| Moisture sensitivity level 1 | No bake preconditioning required prior to reflow, reducing manufacturing overhead |
Applications
| Automotive Power Distribution | On-Board DC/DC Converters |
|---|---|
Use Scenario: Protection of 48V/12V power distribution networks against load dump and jump-start surges in body control modules. IC Role / Device Role / Timing Role: Unidirectional TVS clamp placed across input rails to shunt transient energy to ground. Use Value: Limits clamped voltage to 80.3V, preventing damage to downstream PMICs and microcontrollers rated for ≤100V absolute max. | Use Scenario: Input-side surge suppression in isolated buck-boost converters powering ADAS sensors. IC Role / Device Role / Timing Role: Primary transient absorber at converter input, coordinated with upstream fuse and downstream LC filtering. Use Value: 400W peak power rating handles repetitive ISO 7637-2 Pulse 2b spikes without thermal runaway or parameter shift. |
| Industrial SMPS Inputs | LED Driver Power Stages |
Use Scenario: Front-end protection in DIN-rail mounted switch-mode power supplies exposed to AC line transients. IC Role / Device Role / Timing Role: Standoff-rated TVS connected between L/N and PE to clamp common-mode surges. Use Value: 45V VWM allows use on 36V nominal industrial bus systems while maintaining >10% margin to VBR min. | Use Scenario: Output rail protection in constant-current LED drivers subject to inductive switching transients. IC Role / Device Role / Timing Role: Unidirectional clamp across LED string to prevent reverse-voltage overstress during MOSFET turn-off. Use Value: Cathode-band polarity marking ensures correct orientation; 80.3V VC protects 60V-rated LED driver ICs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ45A | VBR min/max = 50.0/55.3 V - tighter breakdown tolerance vs. SMAJ45CH's 50.0/61.1 V | Lower clamping voltage (72.7 V @ 5.5 A) improves protection margin for 5V-tolerant interfaces | Select SMAJ45A when tighter VBR control and lower VC are prioritized over peak current handling |
| SMBJ45A | Same VWM/VBR specs but in DO-214AA (SMB) package - 2.5× larger thermal mass and 600W PPPM rating | Higher power dissipation capability suits high-repetition-rate transients in motor drives | Choose SMBJ45A where board space permits and 600W surge robustness is required |
Compared with SMAJ45CH, SMAJ45A offers improved clamping consistency at lower cost for fixed-rail designs, while SMBJ45A provides superior thermal endurance in high-energy environments - neither is pin-compatible due to differing DO-214AC vs. DO-214AA footprints.
Availability
SMAJ45CH is available at Aetrix Electronics and suitable for automotive power distribution, on-board DC/DC converters, and industrial SMPS inputs requiring stable component supply with AEC-Q101 traceability and ISO 7637-2 compliance.
Supply support for SMAJ45CH 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 semiconductor manufacturer specializing in discrete power devices, TVS diodes, rectifiers, and MOSFETs for automotive, industrial, and consumer markets.
The SMAJ series was developed specifically for AEC-Q101-compliant transient suppression in harsh automotive environments, emphasizing fast response, stable clamping, and robust packaging for under-hood deployment.
FAQ
What is the polarity configuration of the SMAJ45CH?
The SMAJ45CH is a unidirectional TVS diode with clearly marked cathode band. When installed correctly - cathode to ground, anode to protected line - it clamps reverse transients while presenting high impedance to normal forward-biased operation. This configuration ensures precise 45V stand-off and prevents unintended conduction during positive supply excursions. The SMAJ45CH must not be used in bidirectional applications unless paired with a second device or replaced with a CH-suffixed bipolar variant.
Does the SMAJ45CH meet automotive EMC standards?
Yes, the SMAJ45CH meets ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b requirements for electrical disturbances in road vehicles. Its 400W peak pulse power rating (10/1000μs), sub-1ps response time, and AEC-Q101 qualification confirm suitability for CAN/LIN bus protection, body control modules, and infotainment power rails. Compliance is verified per TSC's official test reports and applies directly to the SMAJ45CH part number.
What is the maximum clamping voltage of the SMAJ45CH under surge conditions?
The SMAJ45CH has a maximum clamping voltage (VC) of 80.3 V at 5.0 A peak impulse current (IPPM), measured using the standard 10/1000μs waveform. This value represents the upper limit of voltage seen by downstream circuitry during worst-case transient events. Designers must ensure that all protected components have absolute maximum ratings exceeding 80.3 V to guarantee survivability - the SMAJ45CH does not regulate voltage but diverts excess energy to ground.
Can the SMAJ45CH be used in bidirectional signal lines?
No, the SMAJ45CH is strictly unidirectional and unsuitable for bidirectional signal protection such as USB or RS-485 without external circuitry. Its asymmetrical I-V curve conducts only in reverse bias above VBR; forward conduction occurs at ~3.5 V, which would disrupt signal integrity. For bidirectional applications, select the SMAJ45CH's bipolar counterpart (e.g., SMAJ45C) or use two SMAJ45CH devices in series opposition - though this increases board area and alters clamping dynamics versus a true bidirectional TVS.
What is the moisture sensitivity level (MSL) of the SMAJ45CH?
The SMAJ45CH has a moisture sensitivity level (MSL) of 1 per J-STD-020, meaning it is not moisture-sensitive and may be stored indefinitely at ambient conditions without baking or dry-pack requirements. This eliminates reflow preparation steps and reduces manufacturing risk in high-volume SMT lines. The MSL-1 rating is confirmed in TSC's official documentation and applies specifically to the DO-214AC packaged SMAJ45CH, not generic variants.
SMAJ45CH 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):
- 45V
- Voltage - Breakdown (Min):
- 50V
- Voltage - Clamping (Max) @ Ipp:
- 80.3V
- Current - Peak Pulse (10/1000µs):
- 5A
- 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)
SMAJ45CH FAQ
1.How can I place an order for SMAJ45CH through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ45CH 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 SMAJ45CH reliable?
The price and inventory of SMAJ45CH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ45CH is usually 5 days.
3.What payment methods are accepted for SMAJ45CH?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ45CH transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ45CH?
SMAJ45CH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ45CH 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 SMAJ45CH?
For technical support, including SMAJ45CH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ45CH requirements.
6.How does Aetrix verify that SMAJ45CH is sourced from the original manufacturer or authorized distributors?
All SMAJ45CH 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 SMAJ45CH meets industry standards.
7.What is the process for return or replacement of SMAJ45CH?
All SMAJ45CH units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ45CH, 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 SMAJ45CH part is unused and in its original packaging.
Return procedure for SMAJ45CH:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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