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onsemi SZMMBZ5257BLT1G
- Part No.:
- SZMMBZ5257BLT1G
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
SZMMBZ5257BLT1G.pdf
- Description:
- DIODE ZENER 33V 225MW SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:11,205
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Product details
Overview
SZMMBZ5257BLT1G from onsemi is a 33 V, 225 mW Zener diode in SOT-23 package, designed for precision voltage regulation and overvoltage protection in space-constrained circuits. It delivers 33 V nominal Zener voltage at 3.8 mA test current, with 700 Ω dynamic impedance and ≤0.1 µA leakage at 25 V reverse bias, supporting use in portable power rails and ESD-sensitive signal conditioning.
For engineers reviewing the SZMMBZ5257BLT1G datasheet, pinout, applications, or equivalent options, key selection criteria include Zener voltage tolerance (±5%), thermal resistance (556 °C/W on FR-5), AEC-Q101 qualification, and 16 kV HBM ESD rating - all critical for automotive and high-reliability portable designs.
Technical Context
This device operates as a two-terminal voltage reference using avalanche breakdown in silicon PN junction. Its 33 V nominal Zener voltage falls within the 2.4–91 V family range and exhibits a positive temperature coefficient near zero crossing - typical for mid-voltage Zeners - enabling stable regulation across −65°C to +150°C junction temperature.
The SOT-23 package features cathode-marked polarity, no internal connection on pin 2, and supports automated placement. With 225 W peak pulse power (8 × 20 µs), it handles transient surges while maintaining 225 mW steady-state dissipation on FR-5 board - derated linearly above 25°C ambient.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 31.35–34.65 V at 3.8 mA - ensures ±5% regulation window for 33 V nominal rail stabilization |
| Power Dissipation (PD) | 225 mW on FR-5 board - defines maximum continuous DC power handling without heatsinking |
| Zener Impedance (ZZT) | 700 Ω at IZT = 3.8 mA - indicates voltage regulation sensitivity to load current changes |
| Leakage Current (IR) | ≤0.1 µA at VR = 25 V - guarantees minimal standby current draw in battery-powered systems |
| ESD Rating | Class 3 (>16 kV HBM) - enables direct integration into handheld and automotive interface nodes without external ESD clamps |
| Junction Temp Range | −65°C to +150°C - supports operation in under-hood automotive and industrial environments |
| Thermal Resistance (RJA) | 556 °C/W on FR-5 - determines temperature rise per milliwatt, critical for thermal margin analysis |
Pinout & Package
Package: SOT-23 (TO-236), 2.90 × 1.30 × 1.00 mm, Pb-free, void-free thermosetting plastic case with corrosion-resistant finish. Cathode indicated by band; pin 2 is unconnected.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Anode | Forward-biased terminal during conduction; connects to lower-potential side of regulated node |
| 2 | No Connection | Internally isolated; must remain floating - no PCB trace or pad required |
| 3 | Cathode | Zener breakdown terminal; connects to higher-potential side and serves as voltage reference output |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 Qualified | Validated for automotive applications including engine control modules and infotainment power supplies |
| 225 mW Continuous Power | Enables compact voltage clamping without external heat sinking on standard FR-5 PCBs |
| 16 kV HBM ESD Robustness | Eliminates need for discrete ESD protection in USB, sensor, and I/O interface lines |
| Low Leakage (≤0.1 µA) | Preserves battery life in always-on circuits such as real-time clock backup and low-power MCU reset rails |
| Pb-Free & RoHS Compliant | Meets global environmental compliance requirements for consumer, industrial, and automotive end equipment |
Applications
| Automotive Body Control Module | Portable Medical Sensor Interface |
|---|---|
|
Use Scenario: Voltage clamping on LIN bus transceiver supply rail subject to load dump transients. IC Role / Device Role / Timing Role: Zener diode providing overvoltage protection and stable 33 V reference for regulator feedback. Use Value: Withstands 225 W pulse energy and maintains <0.1 µA leakage, ensuring system reliability during cold-crank and jump-start events. |
Use Scenario: Precision reference and ESD protection for analog front-end of wearable ECG amplifier. IC Role / Device Role / Timing Role: Dual-function Zener regulating bias voltage while shunting ESD strikes on electrode inputs. Use Value: 16 kV HBM rating and 700 Ω impedance enable direct integration without added TVS or RC filtering, reducing BOM count. |
| Industrial PLC I/O Protection | Smartphone Camera Module Power Rail |
|
Use Scenario: Overvoltage suppression on 24 V digital input channel exposed to field wiring surges. IC Role / Device Role / Timing Role: Fast-response Zener clamp limiting transient voltage to safe levels for downstream logic ICs. Use Value: 8 × 20 µs pulse capability and −65°C to +150°C operation ensure robustness in factory-floor environments. |
Use Scenario: Voltage regulation and surge protection for CIS image sensor bias supply in tight-space camera module. IC Role / Device Role / Timing Role: Compact 33 V Zener stabilizing analog supply while absorbing ESD from lens actuator flex cables. Use Value: SOT-23 footprint and 2.90 × 1.30 mm size allow placement directly adjacent to sensor die, minimizing parasitic inductance. |
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-C33LT1G | 33 V nominal, 300 mW PD, 60 Ω ZZT, non-AEC-Q101 | Larger Zener impedance and no automotive qualification limit use to commercial-grade consumer products | Select when lower dynamic impedance is prioritized over automotive compliance and thermal derating margin |
| SZBZX84C33LT1G | 33 V nominal, 300 mW PD, 60 Ω ZZT, AEC-Q101 qualified | Higher power rating but same 33 V regulation; requires layout review for thermal dissipation differences | Choose for automotive applications needing tighter voltage regulation and higher pulse energy handling than SZMMBZ5257BLT1G |
Compared with BZX84-C33LT1G and SZBZX84C33LT1G, SZMMBZ5257BLT1G offers lower power dissipation (225 mW vs. 300 mW) and higher Zener impedance (700 Ω vs. 60 Ω), making it better suited for low-current reference and ESD clamping where precision is secondary to footprint and qualification - not for high-stability feedback loops.
Availability
SZMMBZ5257BLT1G is available at Aetrix Electronics and suitable for automotive body electronics, portable medical devices, industrial I/O modules, and smartphone camera subsystems requiring stable component supply and AEC-Q101-compliant sourcing.
Supply support for SZMMBZ5257BLT1G 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 is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.
SZMMBZ5257BLT1G belongs to the SZMMBZ52xxELT1G series - engineered for automotive-grade voltage regulation and transient suppression in space-constrained, high-reliability systems.
FAQ
What is the Zener voltage tolerance of SZMMBZ5257BLT1G?
The SZMMBZ5257BLT1G has a Zener voltage range of 31.35 V to 34.65 V at 3.8 mA test current, corresponding to a ±5% tolerance around the nominal 33 V rating. This tolerance is specified at TA = 25°C and applies to all units in the production lot, enabling predictable regulation in feedback and clamping circuits without binning.
Is SZMMBZ5257BLT1G suitable for automotive applications?
Yes, SZMMBZ5257BLT1G is AEC-Q101 qualified and PPAP capable, with manufacturing site and control change tracking enabled by the "SZ" prefix. It meets automotive requirements for temperature cycling, humidity resistance, and transient robustness - confirmed in onsemi's qualification report for the SZMMBZ52xxELT1G series.
What is the thermal resistance of SZMMBZ5257BLT1G on FR-5 board?
The thermal resistance from junction to ambient (RJA) for SZMMBZ5257BLT1G is 556 °C/W when mounted on FR-5 board per the datasheet's Note 2. This value assumes standard 1.0 × 0.75 × 0.62 inch board dimensions and defines the temperature rise per milliwatt of dissipated power under natural convection conditions.
Does SZMMBZ5257BLT1G have an internal connection on pin 2?
No, pin 2 of SZMMBZ5257BLT1G is explicitly designated as "No Connection" in the datasheet's pinout diagram (Style 8) and Electrical Characteristics table. It is internally unconnected and must remain electrically floating - no trace, pad, or solder joint should be assigned to this terminal in PCB layout.
What is the maximum reverse leakage current for SZMMBZ5257BLT1G?
The maximum reverse leakage current (IR) for SZMMBZ5257BLT1G is 0.1 µA at VR = 25 V and TA = 25°C, as specified in the Electrical Characteristics table. This ultra-low leakage supports long battery life in always-on monitoring circuits and prevents unintended discharge in backup power paths.
SZMMBZ5257BLT1G Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- TO-236-3, SC-59, SOT-23-3
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 33 V
- Tolerance:
- ±5%
- Power - Max:
- 225 mW
- Impedance (Max) (Zzt):
- 58 Ohms
- Current - Reverse Leakage @ Vr:
- 100 nA @ 25 V
- Voltage - Forward (Vf) (Max) @ If:
- 900 mV @ 10 mA
- Operating Temperature:
- -65°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-3 (TO-236)
SZMMBZ5257BLT1G FAQ
1.How can I place an order for SZMMBZ5257BLT1G through Aetrix?
Please submit a Request for Quotation (RFQ) for SZMMBZ5257BLT1G 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 SZMMBZ5257BLT1G reliable?
The price and inventory of SZMMBZ5257BLT1G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SZMMBZ5257BLT1G is usually 5 days.
3.What payment methods are accepted for SZMMBZ5257BLT1G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SZMMBZ5257BLT1G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SZMMBZ5257BLT1G?
SZMMBZ5257BLT1G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SZMMBZ5257BLT1G 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 SZMMBZ5257BLT1G?
For technical support, including SZMMBZ5257BLT1G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SZMMBZ5257BLT1G requirements.
6.How does Aetrix verify that SZMMBZ5257BLT1G is sourced from the original manufacturer or authorized distributors?
All SZMMBZ5257BLT1G 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 SZMMBZ5257BLT1G meets industry standards.
7.What is the process for return or replacement of SZMMBZ5257BLT1G?
All SZMMBZ5257BLT1G units undergo pre-shipment inspection (PSI). If there is an issue with SZMMBZ5257BLT1G, 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 SZMMBZ5257BLT1G part is unused and in its original packaging.
Return procedure for SZMMBZ5257BLT1G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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