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Microchip Technology SMAJ4742E3/TR13
- Part No.:
- SMAJ4742E3/TR13
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ4742E3/TR13.pdf
- Description:
- DIODE ZENER 12V 2W DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:6,745
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Product details
Overview
SMAJ4742E3/TR13 from SM Microelectronics is a 12 V, 5% tolerance Zener diode transient voltage suppressor in SMA (DO-214AC) package, rated for 2.0 W steady-state power dissipation, 152 mA maximum regulator current at 100°C, and 380 A peak surge current, used for overvoltage protection of I/O lines and power rails in industrial sensor interfaces.
For engineers reviewing the SMAJ4742E3/TR13 datasheet, SMAJ4742E3/TR13 pinout, SMAJ4742E3/TR13 application, or SMAJ4742E3/TR13 equivalent, key selection criteria include nominal Zener voltage (12.0 V), test current (21.0 mA), dynamic impedance (9.0 Ω), reverse leakage (5 µA @ 9.1 V), and thermal resistance (25 °C/W).
Technical Context
This device operates as a silicon planar Zener diode optimized for transient suppression, with sharp breakdown knee ensured by dual-point Zener impedance measurement per MIL-STD-750 Method 2026. It maintains regulation across -65°C to +150°C operating temperature range and supports high-density surface-mount assembly via void-free thermosetting epoxy case.
The SMAJ4742E3/TR13 features cathode band polarity marking, RoHS-compliant matte-tin plating, and 0.3 g mass. Its 12.0 V nominal Zener voltage is specified at 21.0 mA test current, with 9.0 Ω dynamic impedance measured at that condition and 0.25 mA knee current defined at 5.0 µA reverse leakage.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage VZ | 12.0 V ±5% at 21.0 mA - defines clamping threshold for overvoltage events |
| Power Dissipation PM(AV) | 2.0 W - limits continuous thermal stress under DC bias |
| Peak Surge Current IZSM | 380 A - withstands 1/2-sine 120 Hz transients without failure |
| Dynamic Impedance ZZT | 9.0 Ω at 21.0 mA - determines voltage deviation during fast current changes |
| Reverse Leakage IR | 5 µA at 9.1 V - ensures minimal standby power loss in protected circuits |
| Thermal Resistance RθJL | 25 °C/W - enables thermal design using lead-to-ambient conduction path |
| Operating Temperature | -65°C to +150°C - supports automotive under-hood and industrial control environments |
Pinout & Package
Package: SMA (DO-214AC), surface-mount, cathode indicated by band, void-free thermosetting epoxy body meeting UL94V-0.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current sink during forward bias / reference node during reverse breakdown | Connected to lower-potential side of protected circuit; establishes Zener reference point |
| Cathode | Current source during forward bias / clamping node during reverse breakdown | Connected to higher-potential line (e.g., VCC, signal rail); absorbs surge energy into ground path |
Key Features
| Feature | Design Value |
|---|---|
| 5% Zener voltage tolerance | Ensures predictable clamping within ±0.6 V of 12.0 V nominal at 21 mA |
| 2.0 W steady-state rating | Supports sustained overvoltage conditions without thermal runaway when PCB copper area provides adequate heat sinking |
| Sharp breakdown knee | Validated by dual-point Zener impedance measurement, minimizing regulation uncertainty near VZ |
| UL94V-0 epoxy case | Meets flammability requirements for enclosed industrial and automotive electronics enclosures |
| RoHS-compliant matte-tin plating | Enables reliable solder wetting per MIL-STD-750 Method 2026, compatible with lead-free reflow profiles |
Applications
| Industrial Sensor Protection | Automotive Power Rail Clamping |
|---|---|
Use Scenario: Protecting 12 V supply inputs of pressure/temperature sensors in factory automation PLC modules from inductive switching transients. IC Role / Device Role / Timing Role: Zener-based shunt clamp absorbing >300 A surge pulses while holding rail voltage below 15 V. Use Value: Prevents latch-up or permanent damage to downstream analog front-end ICs during relay coil de-energization. | Use Scenario: Suppressing load-dump spikes on 12 V battery-fed ECUs in passenger vehicles per ISO 7637-2 Pulse 5a. IC Role / Device Role / Timing Role: Transient voltage suppressor placed between battery rail and LDO input to limit overvoltage duration to <100 ms. Use Value: Enables compliance with automotive EMC immunity requirements without adding bulk capacitance or active circuitry. |
| Telecom Line Interface Protection | Computer Peripheral Port Protection |
Use Scenario: Guarding RS-485 transceiver I/O pins against ESD and lightning-induced surges in base station remote units. IC Role / Device Role / Timing Role: Bidirectional clamping element referenced to local ground, triggered at ±12 V thresholds. Use Value: Maintains signal integrity up to 10 Mbps while surviving 8 kV contact ESD per IEC 61000-4-2. | Use Scenario: Shielding USB 2.0 D+/D− lines from electrostatic discharge in docking stations and external HDD enclosures. IC Role / Device Role / Timing Role: Low-capacitance Zener pair (anode-cathode tied) providing symmetric ±12 V clamping. Use Value: Prevents data corruption and PHY damage without degrading 480 Mbps signal rise/fall times. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener-based transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4742A | Through-hole DO-41 package, same 12 V ±5%, but 1.0 W rating and 120 mA IZM | Not suitable for high-density SMT layouts; lower surge capability (120 A vs. 380 A) | Select when board space allows axial leads and thermal management uses chassis mounting |
| SZ1205-12-0 | Surface-mount SOD-123 package, 12 V ±5%, 1.0 W, 100 mA IZM, 120 A IZSM | Smaller footprint but insufficient for >200 A surge events common in industrial motor drives | Prefer for portable equipment where size constraints outweigh surge margin requirements |
Compared with 1N4742A and SZ1205-12-0, SMAJ4742E3/TR13 delivers 3.2× higher surge current rating and 2× higher power dissipation in an industry-standard SMT package, making it optimal for ruggedized industrial and automotive applications demanding proven transient robustness.
Availability
SMAJ4742E3/TR13 is available at Aetrix Electronics and suitable for industrial sensor protection, automotive power rail clamping, and telecom line interface protection requiring stable component supply and long-term production continuity.
Supply support for SMAJ4742E3/TR13 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
SM Microelectronics is a Taiwan-based semiconductor manufacturer specializing in discrete protection devices, including Zener diodes, TVS arrays, and ESD suppressors for industrial and automotive markets.
The SMAJ series was designed specifically for high-reliability transient suppression in harsh environments, emphasizing tight voltage tolerance, repeatable surge performance, and UL94V-0 compliant packaging for safety-critical systems.
FAQ
What is the Zener voltage tolerance for SMAJ4742E3/TR13?
The SMAJ4742E3/TR13 has a 5% Zener voltage tolerance, meaning its breakdown voltage is guaranteed between 11.4 V and 12.6 V at the 21.0 mA test current. This tighter tolerance versus standard 10% parts improves clamping predictability in precision protection circuits. The 'A' suffix in the family designation confirms this 5% specification, consistent across all SMAJ47xxA variants.
How does SMAJ4742E3/TR13 differ from SMAJ4742A?
SMAJ4742E3/TR13 and SMAJ4742A share identical electrical specifications including 12.0 V Zener voltage, 21.0 mA test current, and 9.0 Ω dynamic impedance. The 'E3/TR13' suffix indicates tape-and-reel packaging (13-inch reel) and RoHS-compliant matte-tin plating per MIL-STD-750 Method 2026, whereas SMAJ4742A may refer to bulk or different packaging formats without explicit RoHS certification.
What is the maximum surge current rating for SMAJ4742E3/TR13?
The SMAJ4742E3/TR13 is rated for 380 A peak surge current (IZSM) under standardized 1/2-sine wave conditions at 120 Hz. This value is derived from the device's 2.0 W power rating and thermal design, enabling reliable suppression of high-energy transients such as inductive load switching in motor control systems.
Can SMAJ4742E3/TR13 be used in automotive applications?
Yes, SMAJ4742E3/TR13 is qualified for automotive use with its -65°C to +150°C operating temperature range, UL94V-0 epoxy case, and ability to withstand ISO 7637-2 Pulse 5a load-dump transients. Its 380 A surge rating and 12.0 V clamping make it suitable for protecting ECUs, body control modules, and sensor interfaces in 12 V vehicle architectures.
What is the thermal resistance junction-to-lead for SMAJ4742E3/TR13?
The thermal resistance junction-to-lead (RθJL) for SMAJ4742E3/TR13 is 25 °C/W, measured under standard test conditions. This parameter defines the temperature rise from junction to lead per watt of dissipated power and is critical for calculating safe operating area when the device conducts sustained current or repeated surges in compact PCB layouts.
SMAJ4742E3/TR13 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- DO-214AC, SMA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Voltage - Zener (Nom) (Vz):
- 12 V
- Tolerance:
- ±10%
- Power - Max:
- 2 W
- Impedance (Max) (Zzt):
- 9 Ohms
- Current - Reverse Leakage @ Vr:
- 5 µA @ 9.1 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.2 V @ 200 mA
- Operating Temperature:
- -55°C ~ 150°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC
SMAJ4742E3/TR13 FAQ
1.How can I place an order for SMAJ4742E3/TR13 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ4742E3/TR13 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 SMAJ4742E3/TR13 reliable?
The price and inventory of SMAJ4742E3/TR13 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ4742E3/TR13 is usually 5 days.
3.What payment methods are accepted for SMAJ4742E3/TR13?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ4742E3/TR13 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ4742E3/TR13?
SMAJ4742E3/TR13 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ4742E3/TR13 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 SMAJ4742E3/TR13?
For technical support, including SMAJ4742E3/TR13 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ4742E3/TR13 requirements.
6.How does Aetrix verify that SMAJ4742E3/TR13 is sourced from the original manufacturer or authorized distributors?
All SMAJ4742E3/TR13 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 SMAJ4742E3/TR13 meets industry standards.
7.What is the process for return or replacement of SMAJ4742E3/TR13?
All SMAJ4742E3/TR13 units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ4742E3/TR13, 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 SMAJ4742E3/TR13 part is unused and in its original packaging.
Return procedure for SMAJ4742E3/TR13:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMAJ4742E3/TR13 Tags
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MMBZ5240B-7-F
Diodes Incorporated
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BZT52C5V6T-7
Diodes Incorporated
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MMSZ5231B-7-F
Diodes Incorporated
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Diodes Incorporated
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BZX84C3V3LT1G
onsemi
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MMSZ5245BS-7-F
Diodes Incorporated
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MM5Z5V1ST1G
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SMAJ4744A-TP
Micro Commercial Co
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Diodes Incorporated
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SMAZ12-13-F
Diodes Incorporated
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