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Taiwan Semiconductor Corporation 1SMB5938
- Part No.:
- 1SMB5938
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- Single Zener Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
1SMB5938.pdf
- Description:
- DIODE ZENER 36V 3W DO214AA
- Quantity:
- Payment:
- Shipping:
Inventory:3,796
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Product details
Overview
1SMB5938 from Taiwan Semiconductor is a 3 W, 36 V nominal surface-mount Zener diode in DO-214AA (SMB) package, with 5% voltage tolerance, 10.4 Ω dynamic impedance at 38 mA test current, and 27.4 V maximum DC zener current rating. It serves as a precision voltage reference and overvoltage clamp in DC/DC converters and power supply feedback loops.
For engineers reviewing the 1SMB5938 datasheet, 1SMB5938 pinout, 1SMB5938 application, or 1SMB5938 equivalent, key selection criteria include its 36 V nominal zener voltage, 3 W power dissipation at TL = 75°C, 150 °C max junction temperature, low-inductance SMB package, and compliance with J-STD-020 moisture sensitivity level 1.
Technical Context
The 1SMB5938 operates as a single-die, glass-passivated Zener diode optimized for stable voltage regulation under DC bias. Its zener voltage is specified at 34.2–37.8 V (min–max) with 38 mA test current, and it exhibits 10.4 Ω dynamic impedance at that condition, indicating tight regulation capability near nominal operating point.
Thermal performance is defined by 25 °C/W junction-to-lead resistance and 226 °C/W junction-to-ambient resistance. The device supports surge handling per exponential pulse curves (Fig.10), with polarity indicated by cathode band and solderability validated to J-STD-002.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Nominal Zener Voltage | 36 V - precise DC reference voltage at 38 mA test current, ±5% tolerance |
| Power Dissipation (TL = 75°C) | 3 W - maximum continuous power at lead temperature of 75°C, derated 40 mW/°C above |
| Zener Impedance (ZZT) | 10.4 Ω @ 38 mA - low dynamic resistance ensures minimal output voltage variation under load changes |
| Max DC Zener Current (IZM) | 42 mA - maximum steady-state current before thermal runaway risk at TA = 25°C |
| Junction Temperature Range | −55 to +150 °C - enables operation in industrial and automotive ambient environments |
| Package | DO-214AA (SMB) - surface-mount outline with 5 mm × 4.5 mm footprint and cathode band polarity marking |
| Moisture Sensitivity Level | Level 1 per J-STD-020 - no dry-pack or bake requirement prior to reflow assembly |
Pinout & Package
DO-214AA (SMB) package: molded plastic case with matte tin-plated leads, UL 94V-0 rated compound, and cathode polarity indicated by a visible band on the body.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal | Connected to lower potential side in reverse-biased regulation configuration |
| Cathode | Zener breakdown terminal | Marked with band; connected to higher potential side to enable controlled reverse conduction at Vz |
Key Features
| Feature | Design Value |
|---|---|
| Glass passivated chip junction | Enhances long-term stability and reliability of zener voltage under thermal cycling and humidity stress |
| Low inductance construction | Minimizes voltage overshoot during fast transient events, critical for SMPS feedback path integrity |
| RoHS and halogen-free compliance | Meets IEC 61249-2-21 and global environmental directives without compromising electrical performance |
| Automated placement compatibility | Standard SMB footprint and lead geometry support high-speed pick-and-place with >99.9% placement yield |
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 clamping element and precision voltage reference for optocoupler-coupled feedback loop. Use Value: Maintains regulated 36 V reference with <10.4 Ω impedance, ensuring stable cross-regulation across multiple outputs. |
Use Scenario: Input rail monitoring and undervoltage lockout (UVLO) threshold setting in point-of-load regulators. IC Role / Device Role / Timing Role: Standalone voltage threshold detector enabling system reset or enable signal generation. Use Value: Delivers repeatable 36 V trip point with ±5% tolerance and −55 to +150 °C operational range. |
| Lighting Application | Adapter |
Use Scenario: Overvoltage protection for LED driver ICs in constant-current streetlight modules. IC Role / Device Role / Timing Role: Transient voltage suppressor and steady-state clamp during line surges or hot-swap events. Use Value: Absorbs 3 W continuously and handles non-repetitive surges up to 1000 W (Fig.10), preventing driver IC latch-up. |
Use Scenario: Output voltage stabilization and fault clamping in AC/DC wall adapters for consumer electronics. IC Role / Device Role / Timing Role: Secondary-side shunt regulator providing coarse output voltage control when primary-side regulation is insufficient. Use Value: Enables cost-effective regulation without optocoupler in low-power adapters, leveraging 36 V nominal Vz and 42 mA IZM. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MMBZ5245B (ON Semiconductor) | 200 mW SOT-23 device; 33 V nominal, ±5%, 100 Ω Zz @ 20 mA | Lower power rating limits use to signal-level clamping, not power-stage regulation | Select for space-constrained PCBs where 3 W dissipation is unnecessary |
| SMBJ36A (Littelfuse) | Transient voltage suppressor (TVS); 36 V standoff, 58.1 V clamping, 600 W peak pulse | Designed for surge suppression, not precision DC regulation; higher leakage and looser voltage tolerance | Choose when protecting against lightning or ESD transients-not for stable reference duties |
Compared with MMBZ5245B and SMBJ36A, the 1SMB5938 uniquely balances 3 W continuous power, 10.4 Ω regulation impedance, and SMB package manufacturability-making it suitable for mid-power DC regulation where both accuracy and thermal robustness are required.
Availability
1SMB5938 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 J-STD-020 Level 1 moisture handling.
Supply support for 1SMB5938 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, analog ICs, and protection components for industrial and consumer markets.
The 1SMB59xx series was designed specifically for surface-mount voltage regulation and clamping in compact, high-efficiency power conversion systems-emphasizing thermal robustness, automated assembly compatibility, and tight parametric consistency.
FAQ
What is the nominal zener voltage and tolerance of the 1SMB5938?
The 1SMB5938 has a nominal zener voltage of 36 V with a tolerance of ±5%, corresponding to a guaranteed range of 34.2 V to 37.8 V at 38 mA test current (IZT). This specification is measured under thermal equilibrium at 25 °C ambient and reflects the device's precision as a DC voltage reference in regulation circuits.
What is the maximum continuous power dissipation for the 1SMB5938?
The 1SMB5938 is rated for 3 W continuous power dissipation when lead temperature (TL) is maintained at 75 °C, with a linear derating of 40 mW/°C above that temperature. At 25 °C ambient, its power rating drops to 550 mW due to higher junction-to-ambient thermal resistance (226 °C/W).
Does the 1SMB5938 require moisture sensitivity handling before reflow?
No-the 1SMB5938 is rated at Moisture Sensitivity Level 1 per J-STD-020, meaning it may be stored indefinitely at ≤30 °C/60% RH and placed directly into reflow without baking or dry-pack requirements. This simplifies manufacturing logistics and reduces assembly risk.
How does the 1SMB5938 compare to TVS diodes like SMBJ36A in overvoltage protection?
Unlike the SMBJ36A TVS diode-which clamps transients at 58.1 V with 600 W peak pulse capability-the 1SMB5938 regulates continuously at ~36 V with 10.4 Ω impedance. It is intended for steady-state voltage reference and moderate surge absorption, not high-energy transient suppression.
What is the zener impedance of the 1SMB5938 and why does it matter?
The 1SMB5938 exhibits 10.4 Ω dynamic impedance (ZZT) at 38 mA test current. This low value means the output voltage varies only ~0.4 V for a 40 mA load change-critical for maintaining regulation accuracy in feedback networks and reference circuits where stability under varying current is essential.
1SMB5938 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Taiwan Semiconductor Corporation
- Series:
- -
- Package/Case:
- DO-214AA, SMB
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 36 V
- Tolerance:
- ±5%
- Power - Max:
- 3 W
- Impedance (Max) (Zzt):
- 38 Ohms
- Current - Reverse Leakage @ Vr:
- 1 µA @ 27.4 V
- Voltage - Forward (Vf) (Max) @ If:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AA (SMB)
1SMB5938 FAQ
1.How can I place an order for 1SMB5938 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMB5938 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 1SMB5938 reliable?
The price and inventory of 1SMB5938 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMB5938 is usually 5 days.
3.What payment methods are accepted for 1SMB5938?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMB5938 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMB5938?
1SMB5938 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMB5938 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 1SMB5938?
For technical support, including 1SMB5938 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMB5938 requirements.
6.How does Aetrix verify that 1SMB5938 is sourced from the original manufacturer or authorized distributors?
All 1SMB5938 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 1SMB5938 meets industry standards.
7.What is the process for return or replacement of 1SMB5938?
All 1SMB5938 units undergo pre-shipment inspection (PSI). If there is an issue with 1SMB5938, 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 1SMB5938 part is unused and in its original packaging.
Return procedure for 1SMB5938:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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