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Microchip Technology SMAJ18E3/TR13
- Part No.:
- SMAJ18E3/TR13
- Manufacturer:
- Microchip Technology
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ18E3/TR13.pdf
- Description:
- TVS DIODE 18VWM 32.2VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:4,010
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Product details
Overview
SMAJ18E3/TR13 from Microsemi is a unidirectional surface-mount Transient Voltage Suppressor (TVS) designed for primary overvoltage protection of DC power rails and signal lines. It features a 18 V reverse standoff voltage (VWM), 20.0 V minimum breakdown voltage (VBR), 32.2 V maximum clamping voltage (VC) at 15.5 A peak pulse current, and 500 W peak pulse power rating per 10/1000 µs waveform - deployed in industrial power supplies and automotive body control modules.
For engineers reviewing the SMAJ18E3/TR13 datasheet, SMAJ18E3/TR13 pinout, SMAJ18E3/TR13 application, or SMAJ18E3/TR13 equivalent, key selection criteria include clamping performance under IEC61000-4-5 secondary lightning surge (42 Ω source), RoHS-compliant matte-tin plating, DO-214AC package thermal resistance (15 °C/W junction-to-lead), and compatibility with automated SMT assembly using EIA-481-1-A 12 mm tape.
Technical Context
This TVS diode operates as a unidirectional avalanche clamp: forward-biased during positive transients on the anode, with cathode band marking polarity. Its <100 ps theoretical response time enables suppression of ESD per IEC61000-4-2 Level 4 (±15 kV contact) and EFT per IEC61000-4-4 (±2 kV).
Rated for -65°C to +150°C operation, it delivers 5 W steady-state dissipation at 75°C lead temperature and withstands 40 A forward surge (8.3 ms half-sine) with ≤3.50 V forward voltage - critical for protecting MOSFET gate drivers and microcontroller I/O pins against inductive kickback.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 18 V - Maximum continuous DC or RMS voltage the device blocks without clamping; sets operating margin above 12–15 V nominal rails. |
| VBR min @ IBR | 20.0 V @ 1 mA - Minimum voltage at which avalanche conduction begins; ensures reliable triggering above normal operating voltage. |
| VC @ IPP | 32.2 V @ 15.5 A - Maximum voltage seen by protected circuit during 10/1000 µs surge; defines worst-case stress on downstream ICs. |
| PPP | 500 W - Peak transient power handling capability; supports robust protection against lightning-induced surges per IEC61000-4-5 Class 3 (42 Ω source). |
| ID @ VWM | 1 µA - Leakage current at standoff voltage; negligible loading on low-power sensor interfaces or battery-backed circuits. |
| Package | DO-214AC (SMA) - Standardized surface-mount outline with 1.70–2.26 mm body width and C-bend leads; compatible with IPC-7351B footprint. |
| tclamp | <100 ps - Theoretical response time from 0 V to VBR; enables effective suppression of nanosecond-scale ESD events before IC damage occurs. |
Pinout & Package
DO-214AC (SMA) package: molded thermosetting epoxy case (UL94V-0), void-free construction, matte-tin plated C-bend leads solderable per MIL-STD-750 Method 2026. Cathode indicated by black band; no polarity marking on bidirectional variants (not applicable to SMAJ18E3/TR13).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Surge current return path | Connected to ground or low-impedance reference; carries full transient current during clamping event. |
| Cathode | Protected line connection | Connected to input rail or signal line; voltage at this terminal is clamped to ≤32.2 V during surge. |
Key Features
| Feature | Design Value |
|---|---|
| RoHS-compliant "e3" suffix | Matte-tin plating meets EU Directive 2011/65/EU; eliminates lead-based solder compatibility concerns in modern assembly lines. |
| 500 W peak pulse power | Withstands 15.5 A @ 10/1000 µs surge without degradation - sufficient for IEC61000-4-5 Class 3 (42 Ω) secondary lightning testing. |
| Low clamping ratio (VC/VBR) | 1.61 (32.2 V / 20.0 V) - Minimizes overvoltage stress on protected ICs compared to higher-ratio suppressors. |
| Moisture sensitivity Level 1 | No dry pack required per IPC/JEDEC J-STD-020B - simplifies handling and eliminates bake-out prior to reflow. |
| Tape-and-reel packaging | EIA-481-1-A compliant: 12 mm carrier tape, 2500 units per 13-inch reel (TR13 suffix) - optimized for high-speed pick-and-place placement. |
Applications
| Industrial Power Supply Input Protection | Automotive Body Control Module (BCM) I/O Protection |
|---|---|
Use Scenario: 24 V DC input stage of programmable logic controller (PLC) power supply exposed to load dump and ISO 7637-2 pulses. IC Role / Device Role / Timing Role: Unidirectional TVS placed between input rail and chassis ground to clamp transients before they reach upstream DC-DC converter ICs. Use Value: Clamps 30 A surge (10/1000 µs) to ≤32.2 V, preventing latch-up or gate oxide rupture in synchronous buck controllers rated for 36 V max input. |
Use Scenario: LIN bus transceiver I/O pins in door module subjected to ESD and cable discharge events. IC Role / Device Role / Timing Role: TVS connected anode-to-ground, cathode-to-LIN line to shunt fast transients while maintaining signal integrity below 20.0 V threshold. Use Value: Sub-100 ps response ensures clamping initiates before LIN transceiver's internal ESD diodes conduct, preserving data reliability during ±8 kV contact discharge. |
| Telecom DSL Line Interface Protection | Medical Patient Monitor Sensor Port Protection |
Use Scenario: Analog front-end of ADSL/VDSL line card interfacing twisted-pair copper lines susceptible to induced surges. IC Role / Device Role / Timing Role: TVS placed differential-mode across line pair (with series impedance) to limit common-mode surge energy entering op-amp input stages. Use Value: 1 µA leakage at 18 V VWM avoids DC offset errors in precision 16-bit ADC reference paths tied to same rail. |
Use Scenario: ECG electrode interface circuit exposed to electrostatic discharge during patient attachment/detachment. IC Role / Device Role / Timing Role: TVS installed on each analog input channel to protect instrumentation amplifier inputs from ±15 kV ESD per IEC61000-4-2. Use Value: 32.2 V clamping voltage stays well below absolute maximum ratings of medical-grade amplifiers (typically ±18 V), preventing permanent input stage damage. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ18A | Same VWM, VBR, VC, and PPP; non-RoHS tin-lead plating; no "e3" suffix. | Limited to legacy industrial systems requiring Pb-containing solder compatibility. | Select SMAJ18A only if RoHS exemption applies and tin-lead assembly process is mandated. |
| SMBJ18A | Same electrical specs but SMB (DO-214AA) package: 3.56 mm width vs. SMA's 2.26 mm max; 100 W lower PPP (400 W). | Lower surge margin; suitable for cost-sensitive consumer electronics where Class 2 IEC61000-4-5 compliance suffices. | Choose SMBJ18A when board space allows wider footprint and 400 W peak power meets system-level surge test requirements. |
Compared with SMAJ18A, SMAJ18E3/TR13 adds RoHS compliance and tape-and-reel logistics; versus SMBJ18A, it provides 100 W higher surge capacity and tighter DO-214AC footprint - making it optimal for space-constrained, high-reliability industrial and automotive designs requiring full Class 3 lightning immunity.
Availability
SMAJ18E3/TR13 is available at Aetrix Electronics and suitable for industrial power supplies, automotive body control modules, telecom line interfaces, and medical sensor ports requiring stable component supply across extended production lifecycles.
Supply support for SMAJ18E3/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
Microsemi (now part of Microchip Technology) is a U.S.-based semiconductor company specializing in high-reliability analog and mixed-signal components for aerospace, defense, and industrial markets.
The SMAJ series was engineered for ruggedized surface-mount transient suppression in harsh environments - delivering consistent 500 W surge capability, wide temperature operation (-65°C to +150°C), and qualification-ready packaging for mission-critical systems.
FAQ
What is the clamping voltage of SMAJ18E3/TR13 under a 10/1000 µs surge?
The SMAJ18E3/TR13 has a maximum clamping voltage (VC) of 32.2 V when subjected to its rated 15.5 A peak pulse current under the standard 10/1000 µs waveform. This value is guaranteed per Microsemi's MSC0270A datasheet and defines the upper voltage limit imposed on protected circuitry during surge events - critical for ensuring downstream ICs remain within their absolute maximum ratings.
Is SMAJ18E3/TR13 RoHS compliant and what does the "e3" suffix indicate?
Yes, SMAJ18E3/TR13 is RoHS compliant. The "e3" suffix explicitly denotes matte-tin plating per EU Directive 2011/65/EU, replacing traditional tin-lead terminations. This ensures compatibility with lead-free reflow profiles and eliminates hazardous substance concerns in final product compliance documentation - a requirement for CE-marked industrial and medical equipment.
What package type does SMAJ18E3/TR13 use and is it compatible with standard SMT assembly?
SMAJ18E3/TR13 uses the DO-214AC (SMA) package, with dimensions conforming to JEDEC standards (max 2.26 mm width, 5.48 mm length). Its C-bend leads and moisture sensitivity Level 1 rating make it fully compatible with standard SMT reflow processes - no pre-bake required - and suitable for high-volume placement using EIA-481-1-A 12 mm tape feeders.
How does SMAJ18E3/TR13 perform in IEC61000-4-5 secondary lightning testing?
SMAJ18E3/TR13 is rated for IEC61000-4-5 secondary lightning protection with 42 Ω source impedance up to Class 3 (VWM ≤24 V), covering its 18 V standoff rating. At 15.5 A peak pulse current, it clamps to 32.2 V - well below typical 36 V-rated DC-DC input limits - enabling robust pass/fail performance in certified test labs without derating or parallel devices.
What is the leakage current specification for SMAJ18E3/TR13 at its rated standoff voltage?
The SMAJ18E3/TR13 exhibits a maximum standby leakage current (ID) of 1 µA at its 18 V reverse standoff voltage (VWM). This ultra-low leakage ensures minimal power loss and zero measurable impact on high-impedance sensor bias networks or battery-operated circuits - a key advantage over higher-leakage alternatives in precision analog and low-power IoT applications.
SMAJ18E3/TR13 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Package/Case:
- DO-214AC, SMA
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 18V
- Voltage - Breakdown (Min):
- 20V
- Voltage - Clamping (Max) @ Ipp:
- 32.2V
- Current - Peak Pulse (10/1000µs):
- 15.5A
- Power - Peak Pulse:
- 500W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -65°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMAJ18E3/TR13 FAQ
1.How can I place an order for SMAJ18E3/TR13 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ18E3/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 SMAJ18E3/TR13 reliable?
The price and inventory of SMAJ18E3/TR13 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ18E3/TR13 is usually 5 days.
3.What payment methods are accepted for SMAJ18E3/TR13?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ18E3/TR13 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ18E3/TR13?
SMAJ18E3/TR13 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ18E3/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 SMAJ18E3/TR13?
For technical support, including SMAJ18E3/TR13 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ18E3/TR13 requirements.
6.How does Aetrix verify that SMAJ18E3/TR13 is sourced from the original manufacturer or authorized distributors?
All SMAJ18E3/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 SMAJ18E3/TR13 meets industry standards.
7.What is the process for return or replacement of SMAJ18E3/TR13?
All SMAJ18E3/TR13 units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ18E3/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 SMAJ18E3/TR13 part is unused and in its original packaging.
Return procedure for SMAJ18E3/TR13:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMAJ18E3/TR13 Tags
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