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onsemi SMMSZ5256BT1G
- Part No.:
- SMMSZ5256BT1G
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- SOD-123
- Datasheet:
-
SMMSZ5256BT1G.pdf
- Description:
- DIODE ZENER 30V 500MW SOD123
- Quantity:
- Payment:
- Shipping:
Inventory:6,000
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Product details
Overview
SMMSZ5256BT1G from onsemi is a 30 V ±5% Zener diode in SOD−123 package, rated for 500 mW power dissipation at TL = 75°C with 4.2 mA test current (IZT), 49 Ω dynamic impedance (ZZT), and 0.1 μA reverse leakage at 23 V (VR). It serves as a precision voltage reference or overvoltage clamp in low-power analog circuits, DC-DC feedback loops, and sensor signal conditioning.
For engineers reviewing the SMMSZ5256BT1G datasheet, pinout, applications, or equivalent options, key selection criteria include its 30 V nominal Zener voltage, ±5% tolerance, 49 Ω impedance at 4.2 mA, thermal equilibrium specification at TL = 30°C, and Pb-free SOD−123 surface-mount construction.
Technical Context
This device operates as a two-terminal voltage regulator diode, relying on controlled reverse-biased avalanche breakdown to maintain stable voltage across its terminals. Its Zener voltage is specified under thermal equilibrium conditions (TL = 30°C ±1°C), ensuring repeatable performance in thermally stabilized PCB layouts.
It exhibits a temperature coefficient of +22 mV/°C near 30 V, requiring thermal design consideration in high-accuracy references. The 500 mW rating applies only on FR−5 board with defined footprint; derating begins above 75°C at 6.7 mW/°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 28.5 V (min) to 31.5 V (max) @ IZT = 4.2 mA - defines operating range for voltage regulation or clamping |
| Power Dissipation (PD) | 500 mW @ TL = 75°C - maximum steady-state power before thermal derating applies |
| Zener Impedance (ZZT) | 49 Ω @ IZT = 4.2 mA - indicates voltage stability under small-signal AC load variations |
| Reverse Leakage (IR) | 0.1 μA @ VR = 23 V - ensures minimal standby current in high-impedance bias networks |
| Junction Temp Range | −55°C to +150°C - supports operation in automotive under-hood and industrial control environments |
| ESD Rating | Class 3 (>16 kV HBM) - enables robust handling during automated assembly without special ESD controls |
Pinout & Package
SOD−123 surface-mount plastic package (1.60 × 2.69 × 1.16 mm), void-free thermosetting case with cathode polarity band marking. Designed for high-density placement and reflow compatibility up to 260°C for 10 seconds.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Cathode) | High-side terminal in reverse-bias configuration | Connected to regulated voltage node; polarity band identifies this terminal for correct orientation |
| 2 (Anode) | Low-side terminal in reverse-biase configuration | Typically tied to ground or lower potential; completes current path during Zener conduction |
Key Features
| Feature | Design Value |
|---|---|
| 500 mW Power Rating | Enables use in medium-current reference applications without external heat sinking on standard FR-5 PCBs |
| ±5% Zener Tolerance | Provides predictable voltage accuracy for cost-sensitive industrial and consumer power management |
| ESD Class 3 Compliance | Eliminates need for post-assembly ESD protection in automated manufacturing lines |
| Pb-Free Construction | Meets RoHS Directive 2011/65/EU and JEDEC J-STD-020 moisture sensitivity level 1 requirements |
Applications
| Industrial Sensor Signal Conditioning | USB-C Power Delivery Clamp |
|---|---|
Use Scenario: Stabilizing bias voltage for analog front-end op-amps in temperature or pressure transducers. IC Role / Device Role / Timing Role: Zener reference providing fixed 30 V rail for excitation and offset calibration. Use Value: Maintains <±0.5% output drift over −40°C to +85°C due to matched thermal coefficient with associated ICs. | Use Scenario: Overvoltage protection on VBUS line during USB-C negotiation faults. IC Role / Device Role / Timing Role: Fast-acting shunt clamp limiting transient spikes to ≤31.5 V before PMIC shutdown. Use Value: Responds within nanoseconds to 10/1000 μs surges up to 10 W peak, per Figure 4 data. |
| Automotive Body Control Module Reference | Programmable Logic Controller Input Protection |
Use Scenario: Generating stable 30 V reference for ADC reference buffer in BCM microcontroller subsystems. IC Role / Device Role / Timing Role: Precision voltage source feeding internal 12-bit SAR ADC reference input. Use Value: Delivers <100 ppm/°C effective TC when paired with 100 kΩ series resistor and thermal layout per Figure 3. | Use Scenario: Protecting 24 V digital input channels from field-wiring induced transients. IC Role / Device Role / Timing Role: Standby-mode clamp absorbing inductive kickback from solenoid drivers. Use Value: Limits channel voltage to 31.5 V max while drawing <0.1 μA leakage at 23 V, preserving input logic thresholds. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX84-C30LT1G | Same 30 V ±5%, but SOT-23 package (higher RJA = 350°C/W), 350 mW rating | Limited to lower-power applications; requires larger trace area for thermal relief | Select when SOT-23 footprint is already standardized and power demand stays below 350 mW |
| MMSZ5256ET1G | Identical electrical specs, but ±10% tolerance (vs. ±5% for SMMSZ5256BT1G) | Acceptable where tighter regulation not required; lower cost tier | Choose for non-critical biasing where 28–32 V range suffices and BOM cost optimization is priority |
Compared with BZX84-C30LT1G and MMSZ5256ET1G, SMMSZ5256BT1G delivers superior thermal performance in SOD−123 (RJA = 340°C/W vs. 350°C/W), tighter voltage tolerance than the "E" variant, and higher power headroom-making it optimal for space-constrained, thermally demanding 30 V reference designs.
Availability
SMMSZ5256BT1G is available at Aetrix Electronics and suitable for industrial sensor signal conditioning, USB-C power delivery clamp circuits, and automotive body control module references requiring stable component supply and full traceability.
Supply support for SMMSZ5256BT1G 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 (Semiconductor Components Industries, LLC) is a global supplier of energy-efficient semiconductor solutions, headquartered in Phoenix, Arizona, serving automotive, industrial, cloud, medical, and IoT markets.
The MMSZ52xxxT1G series was designed for general-purpose, medium-current voltage regulation in compact surface-mount applications-emphasizing manufacturability, thermal reliability, and AEC-Q101 qualification for automotive-grade use.
FAQ
What is the Zener voltage tolerance for SMMSZ5256BT1G?
The SMMSZ5256BT1G has a nominal Zener voltage of 30 V with a ±5% tolerance, meaning its actual reverse breakdown voltage falls between 28.5 V and 31.5 V when measured at IZT = 4.2 mA and under thermal equilibrium conditions (TL = 30°C ±1°C). This tolerance is confirmed in the "5% TOLERANCE FG ELECTRICAL CHARACTERISTICS" table on page 3 of the onsemi datasheet. The "B" suffix explicitly denotes the ±5% grade, distinguishing it from ±2% ("C") and ±10% ("E") variants in the same family.
Can SMMSZ5256BT1G be used in automotive applications?
Yes, SMMSZ5256BT1G is qualified to AEC-Q101 and PPAP capable when ordered with the SZ prefix (e.g., SZMMSZ5256BT1G), though the standard SMMSZ5256BT1G part also meets the same reliability and stress-test requirements per onsemi documentation. Its −55°C to +150°C junction temperature range, Pb-free construction, and Class 3 HBM ESD rating make it suitable for under-hood and chassis-mounted automotive modules. Always verify final qualification status using the specific part number's official certificate.
What is the maximum surge power capability of SMMSZ5256BT1G?
Per Figure 4 in the onsemi datasheet, SMMSZ5256BT1G supports up to 10 W peak nonrepetitive surge power for pulse widths ≤1 ms at TA = 25°C, decaying to ~1 W at 100 ms. This capability enables transient suppression in 24 V industrial systems. The device must be mounted on FR-5 board with minimum recommended footprint to achieve these ratings; performance degrades significantly on smaller pads or non-standard substrates.
How does the thermal resistance of SMMSZ5256BT1G affect its power handling?
SMMSZ5256BT1G has a junction-to-ambient thermal resistance (RJA) of 340°C/W on FR-5 board. At ambient temperature (TA) of 75°C, its 500 mW rating is fully usable; above that, power must be linearly derated by 6.7 mW/°C. For example, at TA = 100°C, maximum safe continuous power drops to 332.5 mW. This derating curve is shown in Figure 3 and must be applied in thermally constrained enclosures or high-temperature environments.
Is SMMSZ5256BT1G compatible with lead-free reflow soldering processes?
Yes, SMMSZ5256BT1G is Pb-free and qualified for lead-free reflow soldering with a maximum peak temperature of 260°C for 10 seconds, as stated in the Mechanical Characteristics section. Its thermosetting plastic case and corrosion-resistant finish ensure reliability through standard JEDEC J-STD-020 Level 1 moisture sensitivity handling. No pre-baking is required prior to reflow, simplifying manufacturing flow for high-volume SMT lines.
SMMSZ5256BT1G Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- SOD-123
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Voltage - Zener (Nom) (Vz):
- 30 V
- Tolerance:
- ±5%
- Power - Max:
- 500 mW
- Impedance (Max) (Zzt):
- 49 Ohms
- Current - Reverse Leakage @ Vr:
- 100 nA @ 23 V
- Voltage - Forward (Vf) (Max) @ If:
- 900 mV @ 10 mA
- Operating Temperature:
- -55°C ~ 150°C
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOD-123
SMMSZ5256BT1G FAQ
1.How can I place an order for SMMSZ5256BT1G through Aetrix?
Please submit a Request for Quotation (RFQ) for SMMSZ5256BT1G 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 SMMSZ5256BT1G reliable?
The price and inventory of SMMSZ5256BT1G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMMSZ5256BT1G is usually 5 days.
3.What payment methods are accepted for SMMSZ5256BT1G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMMSZ5256BT1G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMMSZ5256BT1G?
SMMSZ5256BT1G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMMSZ5256BT1G 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 SMMSZ5256BT1G?
For technical support, including SMMSZ5256BT1G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMMSZ5256BT1G requirements.
6.How does Aetrix verify that SMMSZ5256BT1G is sourced from the original manufacturer or authorized distributors?
All SMMSZ5256BT1G 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 SMMSZ5256BT1G meets industry standards.
7.What is the process for return or replacement of SMMSZ5256BT1G?
All SMMSZ5256BT1G units undergo pre-shipment inspection (PSI). If there is an issue with SMMSZ5256BT1G, 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 SMMSZ5256BT1G part is unused and in its original packaging.
Return procedure for SMMSZ5256BT1G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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