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onsemi 1SMB5953BT3
- Part No.:
- 1SMB5953BT3
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
1SMB5953BT3.pdf
- Description:
- DIODE ZENER 150V 3W SMB
- Quantity:
- Payment:
- Shipping:
Inventory:5,398
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Product details
Overview
1SMB5953BT3 from onsemi is a 3 W surface-mount Zener diode with nominal Zener voltage of 150 V, ±5% tolerance, 2.5 mA test current (IZT), and maximum Zener impedance of 6000 Ω at IZT - designed for precision voltage regulation and overvoltage protection in DC power rails and industrial control circuits.
For engineers reviewing the 1SMB5953BT3 datasheet, pinout, applications, or equivalent options, key selection criteria include its 150 V nominal Zener voltage, 3 W steady-state power rating at TL = 75°C, 226 °C/W junction-to-ambient thermal resistance, and AEC−Q101 qualification status for automotive-grade reliability.
Technical Context
This device operates as a two-terminal voltage reference diode, conducting in reverse breakdown to clamp voltage at its specified Zener level. It exhibits a positive temperature coefficient above ~6 V, with typical θVZ ≈ +0.1 mV/°C for 150 V devices per Figure 4.
Designed for surface-mount assembly on FR-4 PCBs using the SMB (Case 403A) package, it supports top-side or bottom-side mounting and features a modified L-bend lead form for enhanced pad contact area and solder joint reliability under thermal cycling.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 142.5 V (min) to 157.5 V (max) at IZT = 2.5 mA - defines regulated output voltage window under nominal bias |
| Power Dissipation (PD) | 3.0 W @ TL = 75°C - maximum continuous power at lead temperature; derates linearly above 75°C at 25 mW/°C |
| Zener Impedance (ZZT) | 6000 Ω max @ IZT = 2.5 mA - indicates voltage regulation stiffness; higher impedance implies greater sensitivity to load current changes |
| Reverse Leakage (IR) | 0.25 μA max @ VR = 114 V - ensures minimal standby current in high-impedance sensing or hold-up circuits |
| Thermal Resistance (RJA) | 226 °C/W - determines junction temperature rise above ambient; requires adequate copper pour or heatsinking for sustained 3 W operation |
| ESD Rating | Class 3 (>16 kV) HBM - enables robust handling in automated SMT lines without special ESD controls |
| Package | SMB (Case 403A) - standardized surface-mount outline with cathode band marking and Pb-free termination (G suffix) |
Pinout & Package
SMB (Case 403A) plastic surface-mount package with cathode indicated by polarity band; dimensions: 3.56 mm × 4.32 mm × 2.20 mm (L × W × H); modified L-bend leads for improved solder fillet formation and mechanical stability.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / low-voltage reference node | Connected to circuit ground or lower-potential rail during Zener operation; carries full Zener current when regulating |
| Cathode | Reverse breakdown terminal / regulated output node | Connected to input supply or protected node; maintains stable voltage relative to anode during reverse conduction |
Key Features
| Feature | Design Value |
|---|---|
| 3 W Power Rating at Lead Temperature | Enables use in medium-power clamping applications without external heatsinking when mounted on ≥1 in² copper area |
| ±5% Zener Voltage Tolerance | Supports deterministic voltage threshold design for overvoltage cutoff and reference circuits without post-calibration |
| AEC−Q101 Qualified | Validated for automotive electronics including body control modules and powertrain subsystems requiring extended temperature and reliability compliance |
| UL 94 V−0 Flammability Rating | Meets safety standards for enclosed industrial equipment where flame propagation must be suppressed during fault conditions |
| Pb-Free (RoHS Compliant) Construction | Compatible with lead-free reflow profiles (peak 260°C for 10 s) and eliminates hazardous material concerns in global supply chains |
Applications
| Industrial Power Supply Protection | Automotive Body Control Module |
|---|---|
|
Use Scenario: Clamping transient spikes on 13.5–16 V battery-fed microcontroller supply rails during load dump events. IC Role / Device Role / Timing Role: Two-terminal shunt regulator providing fast-response overvoltage limiting upstream of LDOs and MCU VCC. Use Value: Withstands 150 V nominal breakdown and 3 W surge capability, absorbing energy before downstream ICs exceed absolute maximum ratings. |
Use Scenario: Stabilizing reference voltage for analog sensor signal conditioning in door module ECUs. IC Role / Device Role / Timing Role: Precision voltage reference source for ADC biasing and comparator thresholds. Use Value: ±5% tolerance and low leakage (<0.25 μA) ensure consistent reference accuracy across −40°C to +125°C operating range. |
| Telecom Line Card Surge Suppression | Medical Diagnostic Equipment Power Rails |
|
Use Scenario: Secondary overvoltage protection on isolated DC-DC converter outputs feeding FPGA I/O banks. IC Role / Device Role / Timing Role: Standby-mode Zener clamp activated only during fault conditions to prevent latch-up. Use Value: 6000 Ω ZZT limits regulation error under light loads while maintaining fast response to >100 V transients. |
Use Scenario: Providing fail-safe voltage limit on auxiliary 24 V logic rails in imaging subsystems. IC Role / Device Role / Timing Role: Passive overvoltage guard ensuring compliance with IEC 60601-1 creepage and clearance requirements. Use Value: UL 94 V−0 housing and AEC−Q101 qualification support safety-critical design documentation and regulatory audits. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N5953B | Same 150 V nominal Zener voltage and ±5% tolerance, but DO-41 through-hole package; 1.5 W power rating | Requires PCB through-hole mounting and offers lower power handling; unsuitable for high-density SMT layouts | Select when legacy board redesign is impractical and thermal constraints allow ≤1.5 W dissipation |
| SZ1SMB5953BT3G | Identical electrical specs and SMB package; differs only in "SZ" prefix denoting AEC−Q101 qualification and PPAP capability | Required for automotive production programs needing certified process control and traceability documentation | Choose for new automotive designs where PPAP submission and zero-defect manufacturing are mandatory |
Compared with 1SMB5953BT3, 1N5953B trades surface-mount compatibility and power for through-hole ease-of-rework, while SZ1SMB5953BT3G adds automotive qualification overhead without altering electrical behavior - enabling direct substitution only where AEC−Q101 compliance is contractually required.
Availability
1SMB5953BT3 is available at Aetrix Electronics and suitable for industrial power supply protection, automotive body control modules, telecom line card surge suppression, and medical diagnostic equipment power rails requiring stable component supply and long-term obsolescence management.
Supply support for 1SMB5953BT3 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 management, analog, sensors, and connectivity solutions for automotive, industrial, cloud, and consumer markets.
The 1SMB59xxBT3 series belongs to onsemi's high-reliability Zener regulator portfolio, engineered for stable voltage reference and transient suppression in harsh environments - particularly where AEC−Q101 compliance, Pb-free assembly, and surface-mount scalability are critical.
FAQ
What is the Zener voltage tolerance of the 1SMB5953BT3?
The 1SMB5953BT3 has a ±5% Zener voltage tolerance, meaning its nominal 150 V breakdown voltage falls between 142.5 V and 157.5 V when measured at IZT = 2.5 mA and TL = 30°C. This tolerance is explicitly defined in the Electrical Characteristics table on page 3 of the official datasheet and applies to all units regardless of date code or lot.
Can the 1SMB5953BT3 be used in automotive applications?
The 1SMB5953BT3 itself is not AEC−Q101 qualified; however, its automotive-grade counterpart SZ1SMB5953BT3G is fully qualified and PPAP-capable. The 1SMB5953BT3 shares identical electrical parameters and SMB packaging but lacks the controlled manufacturing site and documentation required for automotive production - making it suitable only for non-safety-critical prototyping or industrial use.
What is the maximum steady-state power dissipation for the 1SMB5953BT3 at room temperature?
At TA = 25°C, the 1SMB5953BT3 is rated for 550 mW steady-state power dissipation, derating linearly at 4.4 mW/°C above that temperature. This value is significantly lower than its 3 W rating at TL = 75°C because ambient-based derating accounts for worst-case PCB thermal resistance, whereas lead-temperature rating assumes ideal heat sinking at the package leads.
How does the Zener impedance of the 1SMB5953BT3 affect voltage regulation accuracy?
The 1SMB5953BT3 has a maximum Zener impedance (ZZT) of 6000 Ω at IZT = 2.5 mA. This relatively high impedance means its regulated voltage will vary approximately 15 V for every 2.5 mA change in load current - limiting use to low-current reference or infrequent-clamp applications rather than high-precision active regulation circuits.
Is the 1SMB5953BT3 RoHS compliant and lead-free?
Yes, the "G" suffix in 1SMB5953BT3 indicates Pb-free construction per RoHS Directive 2011/65/EU. The device uses matte tin-plated leads and complies with JEDEC J-STD-020 moisture sensitivity level (MSL) 1, supporting standard lead-free reflow profiles with peak temperature up to 260°C for 10 seconds.
1SMB5953BT3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- DO-214AA, SMB
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Voltage - Zener (Nom) (Vz):
- 150 V
- Tolerance:
- ±5%
- Power - Max:
- 3 W
- Impedance (Max) (Zzt):
- 600 Ohms
- Current - Reverse Leakage @ Vr:
- 1 µA @ 114 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
1SMB5953BT3 FAQ
1.How can I place an order for 1SMB5953BT3 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMB5953BT3 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 1SMB5953BT3 reliable?
The price and inventory of 1SMB5953BT3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMB5953BT3 is usually 5 days.
3.What payment methods are accepted for 1SMB5953BT3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMB5953BT3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMB5953BT3?
1SMB5953BT3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMB5953BT3 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 1SMB5953BT3?
For technical support, including 1SMB5953BT3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMB5953BT3 requirements.
6.How does Aetrix verify that 1SMB5953BT3 is sourced from the original manufacturer or authorized distributors?
All 1SMB5953BT3 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 1SMB5953BT3 meets industry standards.
7.What is the process for return or replacement of 1SMB5953BT3?
All 1SMB5953BT3 units undergo pre-shipment inspection (PSI). If there is an issue with 1SMB5953BT3, 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 1SMB5953BT3 part is unused and in its original packaging.
Return procedure for 1SMB5953BT3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1SMB5953BT3 Tags
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