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onsemi 1SMB5944BT3
- Part No.:
- 1SMB5944BT3
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
1SMB5944BT3.pdf
- Description:
- DIODE ZENER 62V 3W SMB
- Quantity:
- Payment:
- Shipping:
Inventory:8,660
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Product details
Overview
1SMB5944BT3 from onsemi is a 3 W surface-mount Zener diode with nominal Zener voltage of 62 V (±5%), maximum Zener impedance of 6 Ω at 100 mA test current, and reverse leakage current ≤0.25 μA at 47.1 V. It serves as a precision voltage reference or overvoltage clamp in DC power regulation circuits for industrial control modules.
For engineers reviewing the 1SMB5944BT3 datasheet, pinout, applications, or equivalent options, key selection criteria include its 62 V nominal Zener voltage, 3 W steady-state power rating at 75 °C lead temperature, 1500 Ω maximum Zener impedance at knee current, and AEC−Q101 qualification status for automotive-grade reliability.
Technical Context
This device operates as a two-terminal voltage-regulating diode, conducting in reverse breakdown to maintain stable voltage across load. Its thermal resistance from junction-to-lead is 40 °C/W, enabling efficient heat transfer to PCB copper when mounted with zero lead length.
The 1SMB5944BT3 exhibits a positive temperature coefficient above ~6 V, with typical VZ drift of +3.5 mV/°C near 62 V. It supports non-repetitive surge power up to 100 W for 1 ms pulses per Figure 2, and features ESD robustness >16 kV HBM per Class 3 rating.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Nominal Zener Voltage | 62 V ±5% - defines regulated output voltage under 100 mA DC test current (IZT) |
| Maximum Steady-State Power | 3.0 W @ TL = 75°C - usable power dissipation with proper PCB copper heatsinking |
| Zener Impedance | 6 Ω max @ IZT = 100 mA - low dynamic resistance ensures tight voltage regulation under load variation |
| Reverse Leakage Current | ≤0.25 μA @ VR = 47.1 V - minimal standby power loss in high-impedance bias networks |
| Maximum Zener Current | 47.1 A - peak DC current before exceeding 3 W power limit at 62 V |
| Thermal Resistance (Junction-to-Lead) | 40 °C/W - enables thermal design with direct lead-to-copper conduction path |
| ESD Rating | Class 3 (>16 kV) HBM - withstands handling and board-level electrostatic discharge events |
Pinout & Package
Package: SMB (Case 403A), surface-mount plastic package with modified L-bend leads, cathode indicated by polarity band. Dimensions per ON Semiconductor drawing CASE 403A−03: D = 3.30–3.95 mm, E = 4.06–4.60 mm, L = 0.76–1.60 mm.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / Zener cathode reference | Connected to lower-potential node; reverse bias applied between cathode and anode to activate regulation |
| Cathode | Zener breakdown terminal / voltage reference output | Marked with band; delivers regulated 62 V when reverse biased and current ≥ IZK (1 mA) |
Key Features
| Feature | Design Value |
|---|---|
| 3 W power rating at TL = 75°C | Enables compact voltage clamping in space-constrained industrial power supplies without forced air cooling |
| AEC−Q101 qualified | Validated for automotive electronics applications requiring extended temperature operation (−65 °C to +150 °C) |
| Pb−Free (RoHS-compliant) packaging | Meets global environmental compliance requirements without compromising solderability or thermal performance |
| Flat handling surface | Ensures consistent pick-and-place accuracy during automated SMT assembly on high-volume production lines |
| UL 94 V−0 flammability rating | Provides fire safety assurance in enclosed equipment housings and safety-critical power systems |
Applications
| Industrial Power Supply Clamp | Automotive ECU Voltage Reference |
|---|---|
Use Scenario: Clamping transient spikes on 48 V DC bus in programmable logic controller (PLC) backplane. IC Role / Device Role / Timing Role: Two-terminal shunt regulator absorbing surge energy to protect downstream DC/DC converters. Use Value: Limits voltage to ≤65.1 V (VZ max) during 100 W/1 ms surges, preventing MOSFET gate oxide failure. |
Use Scenario: Providing stable 62 V reference for analog sensor signal conditioning in engine control unit (ECU) power management ASIC. IC Role / Device Role / Timing Role: Precision Zener reference source for ADC biasing and comparator thresholds. Use Value: Maintains ±5% voltage tolerance across −40 °C to +125 °C ambient, meeting AEC−Q101 thermal stability requirements. |
| Telecom Line Card Protection | Renewable Energy Inverter Snubber |
Use Scenario: Overvoltage protection on -48 V telecom distribution rail against lightning-induced transients. IC Role / Device Role / Timing Role: Fast-acting shunt clamp activated at 62 V to divert surge current away from sensitive line interface ICs. Use Value: Withstands 100 W non-repetitive pulses (Figure 2) and exhibits <1 ns response time to protect 10/100 Mbps Ethernet PHYs. |
Use Scenario: Snubbing voltage overshoot across IGBT collector-emitter during turn-off in solar microinverter DC link. IC Role / Device Role / Timing Role: Passive snubber element clamping switching spikes to prevent IGBT avalanche stress. Use Value: 6 Ω Zener impedance at 100 mA ensures rapid voltage stabilization, reducing dv/dt stress and EMI emissions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N5944BRLG | Same 62 V nominal Zener voltage, but DO-41 through-hole package; 1.5 W power rating; no AEC−Q101 qualification | Limited to low-power, non-automotive PCBs where manual assembly or wave soldering is used | Select when legacy through-hole layout exists and thermal demand is ≤1.5 W |
| SZ1SMB5944BT3G | Identical electrical specs and SMB package; "SZ" prefix denotes automotive-specific traceability and PPAP support | Required for Tier 1 automotive BOMs needing full process documentation and change control | Choose for new automotive designs requiring AEC−Q101 PPAP submission and lot traceability |
Compared with 1SMB5944BT3, 1N5944BRLG offers lower cost and legacy compatibility but lacks surface-mount efficiency and automotive qualification, while SZ1SMB5944BT3G adds manufacturing rigor for automotive supply chains without altering electrical behavior.
Availability
1SMB5944BT3 is available at Aetrix Electronics and suitable for industrial power supply clamp, automotive ECU voltage reference, telecom line card protection, and renewable energy inverter snubber applications requiring stable component supply, RoHS compliance, and AEC−Q101–grade reliability.
Supply support for 1SMB5944BT3 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
onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and consumer markets.
The 1SMB5944BT3 belongs to the 1SMB59xxBT3 series of 3 W surface-mount Zener regulators, designed for high-reliability DC voltage reference and overvoltage protection in harsh-environment applications.
FAQ
What is the nominal Zener voltage and tolerance of the 1SMB5944BT3?
The 1SMB5944BT3 has a nominal Zener voltage of 62 V with a tolerance of ±5%, meaning its actual breakdown voltage falls between 58.9 V and 65.1 V when tested at 100 mA (IZT). This specification is measured at TL = 30°C and reflects the device's precision as a voltage reference or clamp in DC power circuits. The 1SMB5944BT3 maintains this tolerance across its qualified operating temperature range.
How much power can the 1SMB5944BT3 dissipate continuously?
The 1SMB5944BT3 is rated for 3.0 W maximum steady-state power dissipation at a lead temperature (TL) of 75°C, with derating of 25 mW/°C above that point. At 25°C ambient (TA), its power rating drops to 550 mW due to higher junction-to-ambient thermal resistance (226 °C/W). Effective PCB copper area is critical to achieve the full 3 W rating, as thermal performance depends on lead-to-copper conduction rather than ambient convection.
Is the 1SMB5944BT3 suitable for automotive applications?
Yes, the 1SMB5944BT3 is AEC−Q101 qualified and PPAP capable, making it suitable for automotive electronic control units (ECUs), body control modules, and infotainment power supplies. It operates across −65 °C to +150 °C and meets stringent reliability and traceability requirements. While the standard 1SMB5944BT3 meets AEC−Q101, the SZ1SMB5944BT3G variant provides additional automotive-specific process controls and documentation for Tier 1 suppliers.
What is the Zener impedance of the 1SMB5944BT3 and why does it matter?
The 1SMB5944BT3 has a maximum Zener impedance (ZZT) of 6 Ω at IZT = 100 mA. This low dynamic resistance ensures minimal voltage deviation under varying load currents - for example, a 10 mA change in Zener current causes only ~60 mV shift in output voltage. Low ZZT is essential for stable reference generation in precision analog circuits and effective transient clamping in power rails where regulation tightness directly impacts system robustness.
Does the 1SMB5944BT3 have RoHS and lead-free compliance?
Yes, the "G" suffix in the ordering code (1SMB5944BT3G) explicitly indicates Pb−Free (RoHS-compliant) packaging. The device uses lead-free terminations and complies with JEDEC J-STD-020 moisture sensitivity level (MSL) requirements. All external surfaces are corrosion resistant and leads are readily solderable using standard reflow profiles, including lead-free SAC305 processes up to 260°C for 10 seconds.
1SMB5944BT3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- DO-214AA, SMB
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Voltage - Zener (Nom) (Vz):
- 62 V
- Tolerance:
- ±5%
- Power - Max:
- 3 W
- Impedance (Max) (Zzt):
- 100 Ohms
- Current - Reverse Leakage @ Vr:
- 1 µA @ 47.1 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.5 V @ 200 mA
- Operating Temperature:
- -65°C ~ 150°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMB
1SMB5944BT3 FAQ
1.How can I place an order for 1SMB5944BT3 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMB5944BT3 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 1SMB5944BT3 reliable?
The price and inventory of 1SMB5944BT3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMB5944BT3 is usually 5 days.
3.What payment methods are accepted for 1SMB5944BT3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMB5944BT3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMB5944BT3?
1SMB5944BT3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMB5944BT3 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 1SMB5944BT3?
For technical support, including 1SMB5944BT3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMB5944BT3 requirements.
6.How does Aetrix verify that 1SMB5944BT3 is sourced from the original manufacturer or authorized distributors?
All 1SMB5944BT3 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 1SMB5944BT3 meets industry standards.
7.What is the process for return or replacement of 1SMB5944BT3?
All 1SMB5944BT3 units undergo pre-shipment inspection (PSI). If there is an issue with 1SMB5944BT3, 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 1SMB5944BT3 part is unused and in its original packaging.
Return procedure for 1SMB5944BT3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1SMB5944BT3 Tags
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