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Vishay General Semiconductor - Diodes Division SML4738A-E3/5A
- Part No.:
- SML4738A-E3/5A
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- Single Zener Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SML4738A-E3/5A.pdf
- Description:
- DIODE ZENER 8.2V 1W DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:7,555
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Product details
Overview
SML4738A-E3/5A from Vishay Semiconductors is a surface-mount Zener diode with nominal Zener voltage 8.2 V, ±5 % tolerance (suffix A), 31 mA test current (IZT), 6 Ω dynamic impedance at IZT, and 1000 mW power dissipation at TL = 75 °C. It operates as a precision voltage reference or overvoltage clamp in low-power DC regulation circuits.
For engineers reviewing the SML4738A-E3/5A datasheet, SML4738A-E3/5A pinout, SML4738A-E3/5A application, or SML4738A-E3/5A equivalent, key selection criteria include Zener voltage accuracy, low dynamic impedance for stable regulation, AEC-Q101 qualification for automotive use, DO-214AC package thermal performance, and surge current rating of 550 mApk.
Technical Context
This device is a single-junction, silicon planar Zener diode optimized for stable voltage regulation under reverse-bias conditions. Its construction enables low Zener impedance (6 Ω at 31 mA) and low regulation factor, supporting tight output voltage control in feedback loops and reference circuits.
Designed for surface-mount assembly on PCBs with copper pad heatsinking, it sustains 260 °C/10 s soldering per terminal and meets MSL level 1 moisture sensitivity. The DO-214AC (SMA) package provides mechanical robustness and thermal path efficiency for continuous 1000 mW dissipation at 75 °C lead temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 8.2 V nominal, ±5 % tolerance - ensures precise clamping or reference within 0.41 V window at 25 °C |
| Test Current (IZT) | 31 mA - operating point where Zener voltage and impedance are specified; defines stable regulation zone |
| Dynamic Impedance (ZZ) | 6 Ω at IZT - low resistance to AC variations improves regulation stability under load transients |
| Power Dissipation (Ptot) | 1000 mW at TL = 75 °C - supports sustained operation with adequate PCB copper heatsinking |
| Surge Current (IRM) | 550 mApk (8.3 ms pulse) - withstands short-duration overvoltage events without degradation |
| Junction Temperature | 150 °C max - enables reliable operation in under-hood automotive or industrial ambient environments |
| Reverse Current (IR) | 0.5 μA max at VR = 6.56 V - ensures minimal leakage in high-impedance bias networks |
Pinout & Package
DO-214AC (SMA) surface-mount package: molded plastic case with cathode band marking; dimensions 4.93 mm × 5.28 mm × 2.29 mm; weight 64 mg; UL 94 V-0 flammability rating; MSL level 1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / Zener cathode reference ground | Connected to circuit ground or lower-potential node; establishes reference polarity for reverse-bias operation |
| Cathode | Zener breakdown terminal / voltage regulation output | Connected to regulated node; supplies stable 8.2 V when reverse-biased above knee voltage |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive-grade reliability including temperature cycling, HTRB, and ESD testing |
| ±5 % Zener voltage tolerance | Tighter regulation than standard ±10 % parts, reducing need for post-regulation trimming |
| Low dynamic impedance (6 Ω) | Minimizes output voltage deviation under varying load currents in feedback references |
| 260 °C/10 s soldering endurance | Compatible with standard reflow profiles without parametric shift or delamination |
| RoHS-compliant, halogen-free | Meets JEDEC JS709A and EU Directive 2011/65/EU for environmentally constrained applications |
Applications
| Automotive Body Control Module (BCM) | Industrial Sensor Signal Conditioning |
|---|---|
Use Scenario: Providing stable 8.2 V reference for microcontroller ADC inputs monitoring battery voltage and door lock status. IC Role / Device Role / Timing Role: Precision voltage reference for analog front-end scaling and fault detection thresholds. Use Value: ±5 % tolerance and low ZZ ensure consistent ADC code mapping across temperature and supply variation. |
Use Scenario: Clamping amplifier output to prevent overvoltage damage during transient surges in 4–20 mA loop transmitters. IC Role / Device Role / Timing Role: Overvoltage protection element placed at op-amp output stage. Use Value: 550 mApk surge rating and 150 °C junction limit enable survival in harsh factory floor environments. |
| Consumer Power Adapter Feedback | Medical Diagnostic Equipment Reference |
Use Scenario: Setting feedback voltage in secondary-side TL431-based flyback converters for USB-C PD adapters. IC Role / Device Role / Timing Role: Zener reference for optocoupler bias network controlling primary-side PWM duty cycle. Use Value: Low regulation factor maintains tight output regulation (< ±2 %) across line/load changes. |
Use Scenario: Generating calibrated bias for photodiode amplifiers in portable blood oximeters. IC Role / Device Role / Timing Role: Low-drift DC reference source for transimpedance amplifier offset setting. Use Value: AEC-Q101 qualification correlates with long-term parameter stability required for clinical-grade accuracy. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX84-C8V2 | Same 8.2 V nominal, ±5 %, but SOT-23 package (smaller footprint, lower Ptot = 300 mW) | Limited to low-power signal-level clamping; unsuitable for >100 mW continuous dissipation | Select when board space is critical and thermal budget allows derating below 300 mW |
| 1N4738A | Same electrical specs (8.2 V, ±5 %, 31 mA IZT), but DO-41 through-hole package | Requires wave soldering or hand assembly; no MSL or reflow compatibility | Select only for legacy through-hole designs or prototyping where rework flexibility is prioritized |
Compared with BZX84-C8V2 and 1N4738A, the SML4738A-E3/5A delivers higher power handling (1000 mW vs. 300 mW or unspecified), AEC-Q101 qualification for automotive deployment, and DO-214AC reflow compatibility-making it optimal for production SMT systems requiring reliability and thermal headroom.
Availability
SML4738A-E3/5A is available at Aetrix Electronics and suitable for automotive body electronics, industrial sensor interfaces, consumer power adapter feedback circuits, and medical diagnostic equipment requiring stable component supply and long-term manufacturability.
Supply support for SML4738A-E3/5A 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
Vishay Intertechnology is a global semiconductor manufacturer specializing in discrete components, sensors, and passive elements with emphasis on reliability, power handling, and automotive qualification.
The SML4738A-E3/5A belongs to Vishay's SML47xxA Zener diode family, engineered for high-stability voltage reference and overvoltage protection in space-constrained, thermally demanding SMT applications.
FAQ
What is the Zener voltage tolerance for SML4738A-E3/5A?
The SML4738A-E3/5A has a Zener voltage tolerance of ±5 % at 25 °C, as indicated by the "A" suffix in the part number. This means its measured VZ falls between 7.79 V and 8.61 V when tested at 31 mA (IZT). The tighter tolerance improves accuracy in voltage reference and feedback applications compared to standard ±10 % Zeners. The SML4738A-E3/5A achieves this via process-controlled doping and post-trim screening.
Is SML4738A-E3/5A qualified for automotive applications?
Yes, the SML4738A-E3/5A is AEC-Q101 qualified, confirming compliance with stress tests including high-temperature reverse bias (HTRB), temperature cycling, and electrostatic discharge (ESD). This qualification applies specifically to the HE3 variant (e.g., SML4738AH-E3/5A); however, the -E3/5A suffix denotes RoHS-compliant commercial grade. For full automotive use, confirm ordering code SML4738AH-E3/5A with your distributor. The SML4738A-E3/5A itself is widely used in automotive BCMs due to its thermal and surge robustness.
What is the maximum power dissipation of SML4738A-E3/5A?
The SML4738A-E3/5A has a maximum power dissipation of 1000 mW at a lead temperature (TL) of 75 °C, as specified in the Absolute Maximum Ratings table. Derating is required above 75 °C - approximately 13.3 mW/°C - down to zero at 150 °C junction temperature. Effective PCB copper area (e.g., 8 mm × 8 mm pads) is essential to maintain TL ≤ 75 °C under continuous load. The SML4738A-E3/5A must not exceed this limit to avoid parametric drift or failure.
Does SML4738A-E3/5A have a cathode marking?
Yes, the SML4738A-E3/5A features a visible cathode band on the DO-214AC (SMA) package body - a white or black stripe near one end - identifying the cathode terminal. This marking aligns with industry-standard polarity convention: cathode connects to the higher-potential node during Zener operation. Correct orientation is critical for proper voltage regulation; reversing the SML4738A-E3/5A will result in forward conduction (~0.7 V drop) instead of 8.2 V breakdown.
What is the surge current rating for SML4738A-E3/5A?
The SML4738A-E3/5A has a peak surge current (IRM) rating of 550 mApk for an 8.3 ms pulse width, per JEDEC method. This non-repetitive rating reflects capability to absorb transient energy without degradation - critical for protecting downstream ICs from load-dump or inductive kick events. The SML4738A-E3/5A maintains this rating across its full operating temperature range and is commonly deployed in automotive and industrial power rails where such transients occur.
SML4738A-E3/5A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Series:
- -
- Package/Case:
- DO-214AC, SMA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 8.2 V
- Tolerance:
- ±5%
- Power - Max:
- 1 W
- Impedance (Max) (Zzt):
- 4.5 Ohms
- Current - Reverse Leakage @ Vr:
- 10 µA @ 6 V
- Voltage - Forward (Vf) (Max) @ If:
- -
- Operating Temperature:
- 150°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SML4738A-E3/5A FAQ
1.How can I place an order for SML4738A-E3/5A through Aetrix?
Please submit a Request for Quotation (RFQ) for SML4738A-E3/5A 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 SML4738A-E3/5A reliable?
The price and inventory of SML4738A-E3/5A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SML4738A-E3/5A is usually 5 days.
3.What payment methods are accepted for SML4738A-E3/5A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SML4738A-E3/5A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SML4738A-E3/5A?
SML4738A-E3/5A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SML4738A-E3/5A 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 SML4738A-E3/5A?
For technical support, including SML4738A-E3/5A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SML4738A-E3/5A requirements.
6.How does Aetrix verify that SML4738A-E3/5A is sourced from the original manufacturer or authorized distributors?
All SML4738A-E3/5A 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 SML4738A-E3/5A meets industry standards.
7.What is the process for return or replacement of SML4738A-E3/5A?
All SML4738A-E3/5A units undergo pre-shipment inspection (PSI). If there is an issue with SML4738A-E3/5A, 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 SML4738A-E3/5A part is unused and in its original packaging.
Return procedure for SML4738A-E3/5A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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