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Taiwan Semiconductor Corporation 1SMA4740
- Part No.:
- 1SMA4740
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- Single Zener Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
1SMA4740.pdf
- Description:
- DIODE ZENER 10V 1.25W DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:12,896
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Product details
Overview
1SMA4740 from Taiwan Semiconductor is a 1 W, 10 V ±5% surface-mount Zener diode in DO-214AC (SMA) package, featuring 7 Ω dynamic impedance at 25 mA test current, <0.25 µA leakage at 7.6 V, and 454 mA non-repetitive peak surge current. It serves as a precision voltage reference and overvoltage clamp in DC power rails and signal conditioning circuits.
For engineers reviewing the 1SMA4740 datasheet, 1SMA4740 pinout, 1SMA4740 application, or 1SMA4740 equivalent, key selection criteria include its 10 V nominal zener voltage with tight ±5% tolerance, low 7 Ω zener impedance at IZT = 25 mA, thermal stability up to TJ = 175°C, and compatibility with automated SMT placement on standard PCBs.
Technical Context
The 1SMA4740 operates as a single-die, glass-passivated Zener diode optimized for stable reverse-bias regulation. Its electrical behavior is defined by a nominal 10 V breakdown at 25 mA, 7 Ω dynamic impedance (ZZT), and 700 Ω knee impedance (ZZK) at 0.25 mA, ensuring predictable clamping across load transients.
Thermal performance is characterized by a maximum junction temperature of 175°C and power derating starting at TA > 25°C (1 W @ 25°C, 1.25 W @ 60°C with RTHJA < 76.8 K/W). Polarity is marked by a cathode band, and moisture sensitivity is rated J-STD-020 Level 1.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VZ @ IZT | 10 V ±5% at 25 mA - defines precise regulation point for feedback loops and reference generation |
| ZZT @ IZT | 7 Ω - ensures minimal output voltage deviation under varying load currents |
| IR @ VR = 7.6 V | <0.25 µA - guarantees negligible standby current in battery-powered protection circuits |
| PD | 1 W continuous - supports robust transient suppression without external heatsinking on standard FR-4 |
| TJ max | 175°C - enables reliable operation in high-temperature industrial environments |
| IFSM | 30 A (8.3 ms half-sine) - withstands common AC line surge events per IEC 61000-4-5 |
| Package | DO-214AC (SMA) - industry-standard SMT footprint compatible with JEDEC MS-013AC |
Pinout & Package
DO-214AC (SMA) package: molded epoxy case with matte tin-plated leads, cathode indicated by band, weight ≈ 0.060 g, UL 94V-0 rated.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal | Connected to lower-potential node in reverse-bias regulation configuration |
| Cathode | Zener breakdown terminal | Connected to regulated voltage rail; polarity band identifies this terminal |
Key Features
| Feature | Design Value |
|---|---|
| Glass passivated junction | Enhances long-term stability and reduces parameter drift under thermal cycling |
| Low inductance construction | Minimizes voltage overshoot during fast transient suppression (e.g., ESD, EFT) |
| J-STD-020 Level 1 moisture sensitivity | Enables direct placement without baking or dry-pack handling |
| RoHS and halogen-free compliance | Meets IEC 61249-2-21 and EU Directive 2011/65/EU for green manufacturing |
Applications
| Power Supply Voltage Reference | Overvoltage Clamp for Microcontroller I/O |
|---|---|
Use Scenario: Stabilizing feedback voltage in adjustable DC-DC converter output stage. IC Role / Device Role / Timing Role: Zener diode provides fixed 10 V reference to error amplifier input. Use Value: Tight ±5% VZ tolerance and 7 Ω ZZT ensure output regulation accuracy within ±1.5% over line/load variations. | Use Scenario: Protecting 3.3 V or 5 V GPIO pins from accidental 12 V misconnection. IC Role / Device Role / Timing Role: Clamps excess voltage to safe level by conducting above 10 V. Use Value: 454 mA peak surge rating absorbs short-duration faults without degradation. |
| Industrial Sensor Signal Conditioning | Automotive Body Control Module Protection |
Use Scenario: Biasing and limiting analog sensor outputs before ADC input. IC Role / Device Role / Timing Role: Limits signal swing to prevent ADC saturation while providing stable bias. Use Value: Low 0.25 µA leakage at 7.6 V avoids loading high-impedance sensor bridges. | Use Scenario: Suppressing load-dump transients on 12 V supply lines in BCM subassemblies. IC Role / Device Role / Timing Role: Shunts energy from ISO 7637-2 Pulse 5a events to ground. Use Value: 30 A IFSM rating handles 12 V system surges up to 100 ms duration per automotive spec. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ON Semiconductor 1N4740A | Same 10 V ±5%, 1 W rating, but DO-41 through-hole package; higher ZZT (10 Ω) | Requires through-hole assembly; unsuitable for high-density SMT layouts | Select when legacy through-hole design or higher surge margin (IFSM = 40 A) is prioritized |
| Vishay 1SMA4740-G3-08 | Identical DO-214AC package, same 10 V/1 W/7 Ω specs, AEC-Q200 qualified | Validated for automotive temperature cycling and vibration; tighter process control | Select for automotive-grade reliability where extended qualification is mandatory |
Compared with 1SMA4740, the 1N4740A requires board redesign for through-hole mounting and offers higher surge current but poorer impedance, while the 1SMA4740-G3-08 delivers identical electrical performance with certified automotive robustness-making it ideal for Tier-1 BOMs requiring AEC-Q200 compliance.
Availability
1SMA4740 is available at Aetrix Electronics and suitable for industrial power supplies, embedded sensor interfaces, and automotive body electronics requiring stable component supply and full traceability.
Supply support for 1SMA4740 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, rectifiers, and protection components since 1979.
The 1SMA47xx series was designed specifically for high-reliability surface-mount voltage regulation and transient suppression in space-constrained industrial and automotive systems.
FAQ
What is the nominal zener voltage and tolerance of the 1SMA4740?
The 1SMA4740 has a nominal zener voltage of 10 V with a standard tolerance of ±5%, measured at 25 mA test current (IZT) with lead temperature maintained at 30°C ±1°C. This tolerance ensures consistent regulation performance across production lots and operating conditions, making the 1SMA4740 suitable for precision reference applications where voltage stability is critical.
What is the maximum continuous power dissipation for the 1SMA4740 at room temperature?
The 1SMA4740 is rated for 1 W maximum continuous power dissipation at ambient temperature (TA) of 25°C with thermal resistance RTHJA < 76.8 K/W. At 60°C ambient, its power rating increases to 1.25 W due to improved thermal coupling on typical PCB layouts. Derating curves in the official datasheet must be consulted for elevated temperature operation.
Does the 1SMA4740 have RoHS and halogen-free compliance?
Yes, the 1SMA4740 meets RoHS Directive 2011/65/EU and is halogen-free per IEC 61249-2-21. These certifications are confirmed in the product's mechanical and environmental specifications section, supporting environmentally compliant manufacturing and end-of-life recycling requirements for global electronics markets.
What is the zener impedance of the 1SMA4740 and why does it matter?
The 1SMA4740 exhibits a dynamic zener impedance (ZZT) of 7 Ω at 25 mA test current. This low value indicates minimal change in output voltage under varying load conditions-critical for maintaining regulation accuracy in feedback networks and reference circuits. Lower ZZT directly improves line and load regulation performance in power supply designs using the 1SMA4740.
How is polarity identified on the 1SMA4740 DO-214AC package?
Polarity on the 1SMA4740 is indicated by a visible cathode band near one end of the DO-214AC (SMA) package body. The banded end corresponds to the cathode terminal, which must be connected toward the higher-potential side of the circuit during reverse-bias operation. This marking aligns with JEDEC standard orientation for SMA diodes and is verified in the package outline drawing of the official datasheet.
1SMA4740 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Taiwan Semiconductor Corporation
- Series:
- -
- Package/Case:
- DO-214AC, SMA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 10 V
- Tolerance:
- ±5%
- Power - Max:
- 1.25 W
- Impedance (Max) (Zzt):
- 7 Ohms
- Current - Reverse Leakage @ Vr:
- 5 µA @ 7.6 V
- Voltage - Forward (Vf) (Max) @ If:
- -
- Operating Temperature:
- -55°C ~ 175°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
1SMA4740 FAQ
1.How can I place an order for 1SMA4740 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMA4740 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 1SMA4740 reliable?
The price and inventory of 1SMA4740 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMA4740 is usually 5 days.
3.What payment methods are accepted for 1SMA4740?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMA4740 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMA4740?
1SMA4740 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMA4740 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 1SMA4740?
For technical support, including 1SMA4740 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMA4740 requirements.
6.How does Aetrix verify that 1SMA4740 is sourced from the original manufacturer or authorized distributors?
All 1SMA4740 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 1SMA4740 meets industry standards.
7.What is the process for return or replacement of 1SMA4740?
All 1SMA4740 units undergo pre-shipment inspection (PSI). If there is an issue with 1SMA4740, 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 1SMA4740 part is unused and in its original packaging.
Return procedure for 1SMA4740:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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