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Taiwan Semiconductor Corporation 1SMA5940
- Part No.:
- 1SMA5940
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- Single Zener Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
1SMA5940.pdf
- Description:
- DIODE ZENER 43V 1.5W DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:5,880
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Product details
Overview
1SMA5940 from Taiwan Semiconductor is a surface-mount 1.5W Zener diode with a nominal zener voltage of 43V (±5%), 8.7mA test current, 950Ω dynamic impedance at IZT, and maximum DC zener current of 32.7mA. It operates within -55°C to +150°C junction temperature range and is used for voltage regulation in on-board DC/DC converters and switching mode power supplies.
For engineers reviewing the 1SMA5940 datasheet, 1SMA5940 pinout, 1SMA5940 application, or 1SMA5940 equivalent, key selection criteria include its DO-214AC (SMA) package, 43V regulation tolerance, low leakage (<0.5µA at VR = 32.7V), JEDEC Class 3B ESD rating, and UL 94V-0 compliant molding compound.
Technical Context
The 1SMA5940 employs a glass-passivated silicon junction optimized for stable voltage reference and transient suppression in compact power rails. Its 950Ω dynamic impedance at 8.7mA ensures predictable regulation under moderate load variation, while the 0.25mA knee test current supports low-current biasing applications.
Designed for surface-mount assembly on 5mm × 5mm copper pads, the device derates linearly above 75°C ambient (20mW/°C), maintaining 1.5W dissipation at TL = 75°C. Polarity is indicated by a cathode band, and terminals are matte tin-plated per J-STD-002 solderability standards.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 40.85–45.15 V (±5% tolerance at IZT = 8.7 mA) |
| Power Dissipation (PD) | 1.5 W (at TL = 75°C on 5 mm × 5 mm Cu pad) |
| Junction Temperature (TJ) | -55°C to +150°C (supports industrial and automotive under-hood environments) |
| Dynamic Impedance (ZZT) | 950 Ω (measured at IZT = 8.7 mA; defines regulation stiffness) |
| Leakage Current (IR) | <0.5 µA at VR = 32.7 V (ensures minimal standby power loss) |
| ESD Rating | Class 3B per JEDEC JS-001 (8 kV HBM; suitable for automated handling) |
| Moisture Sensitivity | Level 1 per J-STD-020 (no floor life limitation; no bake required) |
Pinout & Package
Package: DO-214AC (SMA), surface-mount, single-diode configuration with cathode band polarity marking. Weight: 0.060 g. Molding compound meets UL 94V-0 flammability rating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal | Connected to lower-potential node during reverse-bias regulation |
| Cathode | Zener breakdown terminal | Marked by band; connected to regulated output node; sinks current during clamping |
Key Features
| Feature | Design Value |
|---|---|
| Glass-passivated junction | Enhances long-term stability and reduces parameter drift under thermal cycling |
| Low inductance construction | Minimizes high-frequency ringing during transient clamping in SMPS feedback paths |
| Matte tin-plated leads | Ensures reliable solder wetting and intermetallic formation per J-STD-002 |
| RoHS & halogen-free compliance | Meets IEC 61249-2-21 and EU RoHS Directive 2011/65/EU for green manufacturing |
| JEDEC Class 3B ESD rating | Withstands 8 kV human-body-model discharge without parametric shift or failure |
Applications
| Switching Mode Power Supply (SMPS) | On-Board DC/DC Converter |
|---|---|
Use Scenario: Primary-side overvoltage protection and secondary-side feedback reference in isolated flyback converters. IC Role / Device Role / Timing Role: Zener reference diode providing stable 43V clamp for optocoupler bias and TL431 auxiliary regulation. Use Value: Tight ±5% VZ tolerance and low 950Ω ZZT ensure consistent loop gain and fast transient response across temperature. |
Use Scenario: Input rail clamping and voltage reference in point-of-load (POL) buck regulators for FPGA or ASIC core supplies. IC Role / Device Role / Timing Role: Standby voltage regulator maintaining 43V bias for enable circuitry and supervisor ICs during low-power states. Use Value: Leakage <0.5 µA at 32.7V minimizes quiescent current draw, extending system sleep-mode battery life. |
| Lighting Application | Adapter Circuitry |
Use Scenario: Overvoltage protection for LED driver ICs in constant-current streetlight modules exposed to line surges. IC Role / Device Role / Timing Role: Transient voltage suppressor clamping input transients before they reach PWM controller inputs. Use Value: 1.5W power rating and 10A IFSM withstand capability provide robust surge immunity per IEC 61000-4-5 Level 3. |
Use Scenario: Output voltage stabilization in AC/DC wall adapters powering consumer electronics. IC Role / Device Role / Timing Role: Secondary-side shunt regulator establishing precise 43V reference for TL431-based feedback networks. Use Value: Low-profile DO-214AC package enables high-density PCB layout; moisture level 1 eliminates pre-bake requirements in high-volume SMT lines. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4749A | 43V nominal, ±5%, 1W rating, DO-41 package (axial lead), higher ZZT (1000Ω) | Not surface-mount; requires through-hole assembly and larger board area | Choose 1SMA5940 for automated SMT production; select 1N4749A only if legacy through-hole design or higher surge robustness (1A IFSM) is prioritized over footprint size. |
| BZX84-C43 | 43V nominal, ±5%, 300mW rating, SOT-23 package, ZZT = 90Ω at 5mA | Lower power handling limits use to low-current bias/reference roles; unsuitable for >100mA regulation loads | Use BZX84-C43 where space is critical and power demand is ≤300mW; retain 1SMA5940 for 1.5W continuous dissipation and industrial-grade thermal margin. |
Compared with 1N4749A and BZX84-C43, the 1SMA5940 uniquely balances 1.5W power capability, DO-214AC SMT compatibility, and ±5% tight tolerance-making it optimal for high-reliability, medium-power voltage reference and clamping in modern power supply designs.
Availability
1SMA5940 is available at Aetrix Electronics and suitable for switching mode power supplies, on-board DC/DC converters, and lighting applications requiring stable component supply, RoHS-compliant sourcing, and moisture-level-1 handling.
Supply support for 1SMA5940 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 power management, protection, and signal conditioning devices.
The 1SMA59xx series was developed to deliver high-stability, surface-mount Zener diodes for industrial and consumer power conversion systems demanding tight voltage tolerance, low leakage, and automated assembly readiness.
FAQ
What is the exact zener voltage tolerance and test condition for 1SMA5940?
The 1SMA5940 has a zener voltage tolerance of ±5% at a test current (IZT) of 8.7 mA, with guaranteed minimum and maximum values of 40.85 V and 45.15 V respectively. This specification is validated at thermal equilibrium per datasheet Note 2, and applies strictly under the stated test condition-not at arbitrary currents or temperatures.
Can 1SMA5940 be used in place of 1N4749A in an existing design?
No direct replacement: 1SMA5940 uses a DO-214AC (SMA) surface-mount package, while 1N4749A is DO-41 axial-leaded. Though both are 43V ±5% Zeners, the 1SMA5940 offers higher power (1.5W vs. 1W) and lower dynamic impedance (950Ω vs. 1000Ω), but requires PCB redesign for SMT placement. The 1SMA5940 is not pin-compatible with 1N4749A.
What is the maximum allowable junction temperature and thermal derating behavior of 1SMA5940?
The 1SMA5940 has a maximum junction temperature (TJ) of +150°C. Its power dissipation derates linearly above 75°C lead temperature at 20 mW/°C, maintaining full 1.5W rating only when mounted on a 5 mm × 5 mm copper pad at TL = 75°C. Exceeding TJ = 150°C risks permanent parametric shift or junction failure.
Does 1SMA5940 meet industry-standard ESD and moisture sensitivity requirements?
Yes-the 1SMA5940 is rated JEDEC Class 3B (8 kV HBM) for ESD robustness and moisture sensitivity level 1 per J-STD-020. These certifications confirm suitability for automated placement without dry-packaging or baking, and resilience against electrostatic discharge during handling and assembly.
How does the dynamic impedance of 1SMA5940 affect its performance in voltage reference circuits?
The 1SMA5940 exhibits 950Ω dynamic impedance (ZZT) at 8.7 mA, directly impacting regulation accuracy under load variation. Lower ZZT yields smaller output voltage deviation for a given current change-critical in precision feedback loops. For example, a 10 mA load step causes ~9.5 V shift without compensation, necessitating proper bypassing and current-source biasing in 1SMA5940-based references.
1SMA5940 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):
- 43 V
- Tolerance:
- ±5%
- Power - Max:
- 1.5 W
- Impedance (Max) (Zzt):
- 53 Ohms
- Current - Reverse Leakage @ Vr:
- 500 nA @ 32.7 V
- Voltage - Forward (Vf) (Max) @ If:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
1SMA5940 FAQ
1.How can I place an order for 1SMA5940 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMA5940 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 1SMA5940 reliable?
The price and inventory of 1SMA5940 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMA5940 is usually 5 days.
3.What payment methods are accepted for 1SMA5940?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMA5940 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMA5940?
1SMA5940 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMA5940 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 1SMA5940?
For technical support, including 1SMA5940 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMA5940 requirements.
6.How does Aetrix verify that 1SMA5940 is sourced from the original manufacturer or authorized distributors?
All 1SMA5940 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 1SMA5940 meets industry standards.
7.What is the process for return or replacement of 1SMA5940?
All 1SMA5940 units undergo pre-shipment inspection (PSI). If there is an issue with 1SMA5940, 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 1SMA5940 part is unused and in its original packaging.
Return procedure for 1SMA5940:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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