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Taiwan Semiconductor Corporation SMAJ64AH
- Part No.:
- SMAJ64AH
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ64AH.pdf
- Description:
- TVS DIODE 64VWM 103VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:7,500
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Product details
Overview
SMAJ64AH from Taiwan Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode in DO-214AC (SMA) package, designed for robust overvoltage protection in automotive and industrial DC power rails. It features a 64 V working stand-off voltage (VWM), 71.1–78.6 V breakdown voltage (VBR), 103 V maximum clamping voltage (VC) at 3.9 A peak impulse current, and 400 W peak pulse power rating per 10/1000 µs waveform.
For engineers reviewing the SMAJ64AH datasheet, SMAJ64AH pinout, SMAJ64AH application, or SMAJ64AH equivalent, key selection criteria include clamping performance under ISO 7637-2 Pulse 1/2a/2b/3a/3b transients, AEC-Q101 qualification for automotive use, moisture sensitivity level 1 compliance, and unidirectional polarity marking for correct PCB orientation.
Technical Context
The SMAJ64AH operates as a unidirectional avalanche diode with glass-passivated junction, enabling fast response (<1.0 ps from 0 V to VBR min) and low leakage (<3.9 µA at 64 V). Its clamping behavior is defined by a single-die silicon structure optimized for high-energy surge absorption without thermal runaway under repetitive or single-event transients.
It meets ISO 7637-2 immunity requirements for automotive electronics and supports operation across –55 °C to +150 °C junction temperature range. The device is rated for 40 A non-repetitive forward surge (8.3 ms half-sine) and maintains stable VC up to its 400 W peak pulse limit at TA = 25 °C, derating linearly above that ambient.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 64 V - Maximum continuous reverse operating voltage before significant leakage begins; sets system rail margin for 72 V nominal automotive systems. |
| VBR @ IT = 1 mA | 71.1–78.6 V - Breakdown threshold range; ensures reliable turn-on during transients exceeding normal operating voltage. |
| VC @ IPPM = 3.9 A | 103 V - Clamped voltage during 10/1000 µs surge; defines worst-case stress on downstream ICs in protected circuit. |
| PPPM | 400 W - Peak pulse power handling capability; sufficient for ISO 7637-2 Pulse 1 (–150 V/2 Ω) and Pulse 2b (–100 V/50 Ω) events. |
| IR @ VWM | <3.9 µA - Reverse leakage at stand-off voltage; minimizes quiescent power loss and avoids false triggering in low-power monitoring circuits. |
| TJ max | +150 °C - Maximum junction temperature; enables placement near heat sources in engine control units or DC/DC converters. |
Pinout & Package
DO-214AC (SMA) surface-mount package with cathode band marking for unidirectional polarity. Matte tin-plated leads meet J-STD-002 solderability requirements and JESD 201 Class 2 whisker resistance. Weight: 0.060 g.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side reference terminal | Connected to ground or low-voltage return path; establishes reference for clamping action during positive transients on cathode side. |
| Cathode | Protected line input | Connected to supply rail (e.g., 64 V bus); absorbs energy during overvoltage events by avalanching to clamp voltage at ≤103 V. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive underhood and powertrain applications per stress test requirements including HTOL, TC, HAST, and UHST. |
| Glass passivated junction | Enhances long-term reliability and stability of VBR and leakage under thermal cycling and humidity exposure. |
| Fast response time <1.0 ps | Ensures clamping activation before sensitive downstream components experience damaging voltage overshoot during ESD or load dump. |
| ISO 7637-2 compliant | Meets Pulse 1 (inductive switch-off), Pulse 2a (battery disconnect), Pulse 2b (alternator load dump), and Pulses 3a/3b (capacitive coupling) immunity requirements. |
Applications
| Automotive Power Rail Protection | Industrial DC/DC Converter Input |
|---|---|
Use Scenario: Protecting 64 V battery-fed ECUs against load dump transients up to –100 V per ISO 7637-2 Pulse 2b. IC Role / Device Role / Timing Role: Unidirectional TVS diode placed between battery rail and ground, clamping negative spikes while blocking normal reverse bias. Use Value: Limits voltage seen by MCU power supply ICs to ≤103 V, preventing latch-up or gate oxide damage during alternator field collapse events. | Use Scenario: Safeguarding isolated 64 V input stage of telecom-grade DC/DC converter against lightning-induced surges on long cable runs. IC Role / Device Role / Timing Role: Primary overvoltage clamp on primary-side input, absorbing 400 W pulses without degradation over 100,000+ cycles. Use Value: Enables use of lower-cost 120 V-rated MOSFETs and capacitors instead of 200 V+ rated parts, reducing BOM cost and footprint. |
| LED Driver Supply Protection | On-Board Charger Interface |
Use Scenario: Shielding constant-current LED driver ICs from switching noise and inductive kickback in commercial lighting systems. IC Role / Device Role / Timing Role: Standoff-rated TVS on 64 V bus feeding multi-string LED arrays, activated only during abnormal overvoltage conditions. Use Value: Prevents premature LED string failure due to transient-induced current imbalance across parallel channels. | Use Scenario: Protecting bidirectional communication and power lines in EV on-board chargers exposed to grid-side surges and vehicle-side EMI. IC Role / Device Role / Timing Role: Unidirectional clamping element on HV DC input rail prior to isolation barrier, complementing bidirectional TVS on signal lines. Use Value: Maintains functional safety integrity by limiting fault voltage to <103 V during 10/1000 µs surges, satisfying ASIL-B system-level requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ64H | Higher VBR range (71.1–86.9 V); higher VC = 114 V at 3.5 A; same PPPM and package. | Less precise clamping near 64 V rail; higher let-through voltage may stress downstream 100 V-rated components. | Select SMAJ64H only if tighter VBR tolerance is not required and higher clamping voltage is acceptable. |
| SMBJ64AH | Same VWM/VBR/VC specs but in larger DO-214AA (SMB) package; 600 W PPPM. | Requires larger PCB area; suited for higher-energy transients where 400 W margin is insufficient. | Choose SMBJ64AH when surge energy exceeds SMAJ64AH's 400 W rating or when thermal dissipation demands larger case size. |
Compared with SMAJ64H and SMBJ64AH, the SMAJ64AH delivers optimal balance of precision clamping (71.1–78.6 V VBR, 103 V VC), compact DO-214AC footprint, and AEC-Q101 qualification-making it the preferred choice for space-constrained automotive and industrial 64 V rail protection where consistent low clamping voltage is critical.
Availability
SMAJ64AH is available at Aetrix Electronics and suitable for automotive power rail protection, industrial DC/DC converter input stages, and LED driver supply circuits requiring stable component supply with full traceability and lifecycle support.
Supply support for SMAJ64AH 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 AEC-Q101-compliant automotive transient suppression, targeting 12 V–188 V battery systems with emphasis on low clamping voltage, fast response, and high reliability under thermal and mechanical stress.
FAQ
What is the maximum clamping voltage of the SMAJ64AH under standard test conditions?
The SMAJ64AH has a maximum clamping voltage (VC) of 103 V when subjected to a 10/1000 µs waveform with a peak impulse current (IPPM) of 3.9 A. This value is measured at TA = 25 °C and defines the upper voltage limit imposed on protected circuitry during surge events. The SMAJ64AH maintains this clamping performance consistently across its qualified operating temperature range.
Is the SMAJ64AH suitable for automotive applications requiring AEC-Q101 certification?
Yes, the SMAJ64AH is explicitly AEC-Q101 qualified per the manufacturer's documentation. It undergoes rigorous stress testing-including high-temperature operating life, temperature cycling, and unbiased highly accelerated stress testing-to ensure reliability in automotive underhood and powertrain environments. The SMAJ64AH's qualification covers its full specified operating range and packaging configuration.
How does the SMAJ64AH differ from the SMAJ64H in terms of electrical performance?
The SMAJ64AH offers a tighter breakdown voltage range (71.1–78.6 V) versus SMAJ64H (71.1–86.9 V), resulting in more consistent clamping onset and lower maximum clamping voltage (103 V vs. 114 V). Both share identical VWM (64 V), package (DO-214AC), and peak pulse power (400 W), but the SMAJ64AH provides superior voltage control for precision-sensitive 64 V rail designs.
What is the reverse leakage current specification for the SMAJ64AH at its working stand-off voltage?
The SMAJ64AH exhibits a maximum reverse leakage current (IR) of 3.9 µA when biased at its 64 V working stand-off voltage (VWM) and tested at TA = 25 °C. This low leakage ensures minimal power loss in always-on systems and prevents false triggering in high-impedance sensing or monitoring circuits connected to the protected rail.
Does the SMAJ64AH meet ISO 7637-2 immunity standards for automotive electronics?
Yes, the SMAJ64AH is specified to meet ISO 7637-2 for Pulses 1, 2a, 2b, 3a, and 3b-covering key automotive transient threats including load dump, battery disconnection, and capacitive coupling events. Its 400 W peak pulse rating and 103 V clamping voltage enable compliance with the voltage limits and energy absorption requirements defined in the standard for 64 V system architectures.
SMAJ64AH 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):
- 64V
- Voltage - Breakdown (Min):
- 71.1V
- Voltage - Clamping (Max) @ Ipp:
- 103V
- Current - Peak Pulse (10/1000µs):
- 3.9A
- 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)
SMAJ64AH FAQ
1.How can I place an order for SMAJ64AH through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ64AH 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 SMAJ64AH reliable?
The price and inventory of SMAJ64AH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ64AH is usually 5 days.
3.What payment methods are accepted for SMAJ64AH?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ64AH transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ64AH?
SMAJ64AH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ64AH 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 SMAJ64AH?
For technical support, including SMAJ64AH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ64AH requirements.
6.How does Aetrix verify that SMAJ64AH is sourced from the original manufacturer or authorized distributors?
All SMAJ64AH 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 SMAJ64AH meets industry standards.
7.What is the process for return or replacement of SMAJ64AH?
All SMAJ64AH units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ64AH, 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 SMAJ64AH part is unused and in its original packaging.
Return procedure for SMAJ64AH:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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