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onsemi SZMMBZ5259BLT1G
- Part No.:
- SZMMBZ5259BLT1G
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
SZMMBZ5259BLT1G.pdf
- Description:
- DIODE ZENER 39V 225MW SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:12,286
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Product details
Overview
SZMMBZ5259BLT1G from onsemi is a 39 V ±2.5% Zener voltage regulator diode in SOT-23 package, rated for 225 mW power dissipation on FR-5 board at 25°C, with 80 Ω dynamic impedance at 3.2 mA test current and 0.1 μA leakage current at 30 V reverse bias - used for precision voltage reference and overvoltage protection in portable power rails.
For engineers reviewing the SZMMBZ5259BLT1G datasheet, pinout, applications, or equivalent options, key selection criteria include Zener voltage tolerance (±2.5%), thermal resistance (556 °C/W), AEC-Q101 qualification, ESD rating (>16 kV HBM), and SOT-23 footprint compatibility with high-density PCB layouts.
Technical Context
This device operates as a two-terminal shunt regulator, maintaining stable 39 V output by conducting reverse current above its Zener breakdown threshold. Its 80 Ω Zener impedance at IZT = 3.2 mA ensures low voltage variation under load transients.
Designed for automotive-grade reliability, SZMMBZ5259BLT1G features AEC-Q101 qualification, Pb-free/halogen-free construction, and Class 3 ESD robustness (>16 kV HBM). It exhibits a positive temperature coefficient near 39 V, typical for mid-range Zener voltages.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 37.05 V min / 39 V nominal / 40.95 V max at IZT = 3.2 mA - defines regulated voltage window with ±2.5% tolerance |
| Power Dissipation (PD) | 225 mW on FR-5 board at 25°C - sets maximum continuous power handling before thermal derating begins |
| Zener Impedance (ZZT) | 80 Ω at IZT = 3.2 mA - determines AC voltage regulation stability under small-signal variations |
| Leakage Current (IR) | 0.1 μA at VR = 30 V - ensures minimal standby current draw in undervoltage conditions |
| ESD Rating | Class 3 (>16 kV) per Human Body Model - enables direct integration into handheld and automotive front-end circuits without external ESD protection |
| Thermal Resistance (RJA) | 556 °C/W on FR-5 board - defines junction-to-ambient temperature rise per milliwatt of dissipated power |
| Operating Temperature | −65°C to +150°C - supports deployment in under-hood automotive and industrial environments |
Pinout & Package
SOT-23 (TO-236) surface-mount package, 2.90 mm × 1.30 mm × 1.00 mm body size, cathode indicated by polarity band. Pin 2 is internally unconnected (NC).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Anode | Connected to lower-potential side of regulated rail; reverse-biased during Zener operation |
| 2 | No Connection | Internally isolated; must remain floating - no PCB trace or solder joint required |
| 3 | Cathode | Connected to higher-potential side; carries full Zener current during regulation |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 Qualified | Validated for automotive applications including engine control modules and ADAS sensor power supplies |
| 225 mW Power Rating | Enables compact voltage clamping in space-constrained mobile and IoT designs without heatsinking |
| ESD Robustness >16 kV HBM | Eliminates need for discrete TVS diodes in ESD-prone interfaces like USB or button inputs |
| Pb-Free / Halogen-Free | Complies with RoHS Directive 2011/65/EU and JEDEC J-STD-020 moisture sensitivity level 1 |
| SOT-23 Footprint | Supports automated pick-and-place assembly and reflow soldering per IPC-J-STD-020 standards |
Applications
| Automotive Sensor Power Supply | Portable Device Battery Protection |
|---|---|
Use Scenario: Regulating 39 V reference for analog front-end of radar transceiver power monitor ICs. IC Role / Device Role / Timing Role: Shunt voltage reference providing stable bias point for ADC input scaling and overvoltage detection circuitry. Use Value: Maintains ±2.5% accuracy across −40°C to +125°C ambient, enabling reliable fault detection without calibration drift. |
Use Scenario: Clamping surge voltage on Li-ion battery pack monitoring lines during hot-plug events. IC Role / Device Role / Timing Role: Passive overvoltage protector limiting transient excursions to ≤40.95 V to safeguard fuel gauge IC inputs. Use Value: 0.1 μA leakage at 30 V ensures <1 nA standby current impact on battery capacity estimation accuracy. |
| Industrial PLC Input Protection | Medical Wearable Reference Circuit |
Use Scenario: Protecting 24 V DC input channels of programmable logic controllers against field-wiring transients. IC Role / Device Role / Timing Role: Fast-response shunt clamp absorbing 225 mW surges up to 100 ms duration without degradation. Use Value: 556 °C/W thermal resistance allows safe operation at 85°C ambient with no derating below 150 mW. |
Use Scenario: Generating precise 39 V bias for photodiode transimpedance amplifier in pulse oximeter optical module. IC Role / Device Role / Timing Role: Low-noise voltage reference stabilizing feedback loop gain and offset in analog signal chain. Use Value: 80 Ω Zener impedance minimizes AC ripple coupling into sensitive analog measurement path. |
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-C39LT1G | Same 39 V nominal Zener, but 350 mW rating and 90 Ω ZZT; not AEC-Q101 qualified | Lacks automotive qualification and has higher impedance - suitable for commercial-grade consumer electronics only | Select when cost sensitivity outweighs automotive compliance and tighter regulation is unnecessary |
| SZMMBZ5258BLT1G | 36 V nominal Zener (34.2–37.8 V range), identical package, AEC-Q101 qualified, 70 Ω ZZT at 3.4 mA | Lower voltage grade; used where 36 V system margin is acceptable instead of 39 V | Choose for systems requiring reduced clamping threshold while retaining same automotive qualification and thermal performance |
Compared with SZMMBZ5259BLT1G, BZX84-C39LT1G offers higher power but lacks automotive validation and has looser regulation, whereas SZMMBZ5258BLT1G provides tighter impedance and same qualification at a 3 V lower Zener point - making it a functional alternative only when voltage tolerance permits.
Availability
SZMMBZ5259BLT1G is available at Aetrix Electronics and suitable for automotive sensor modules, portable medical devices, industrial PLC I/O protection, and high-density power management circuits requiring stable component supply with full traceability and long-term lifecycle support.
Supply support for SZMMBZ5259BLT1G 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 silicon solutions for automotive, industrial, cloud, medical, and IoT applications.
SZMMBZ5259BLT1G belongs to the SZMMBZ52xxBLT1G automotive Zener series, designed specifically for AEC-Q101-compliant voltage reference and transient suppression in harsh-environment electronic control units.
FAQ
What is the Zener voltage tolerance of SZMMBZ5259BLT1G?
The SZMMBZ5259BLT1G has a Zener voltage tolerance of ±2.5%, specified as 37.05 V minimum and 40.95 V maximum at test current IZT = 3.2 mA. This tight tolerance ensures predictable clamping behavior in safety-critical automotive and industrial applications where voltage margins must be strictly controlled. The nominal 39 V value is guaranteed across the full operating temperature range of −65°C to +150°C.
Is SZMMBZ5259BLT1G qualified for automotive use?
Yes, SZMMBZ5259BLT1G is AEC-Q101 qualified and PPAP capable, meeting the stress-test requirements for automotive-grade discrete semiconductors. It is manufactured with unique site and process controls denoted by the "SZ" prefix, and supports automotive applications including engine control units, ADAS sensors, and body electronics. Its construction is Pb-free, halogen-free, and RoHS compliant per onsemi's automotive quality standards.
What is the thermal resistance of SZMMBZ5259BLT1G on standard PCB material?
SZMMBZ5259BLT1G has a junction-to-ambient thermal resistance (RJA) of 556 °C/W when mounted on an FR-5 board measuring 1.0 × 0.75 × 0.62 inches. This value defines how much the junction temperature rises per milliwatt of power dissipated - for example, at 225 mW full-rated power, junction temperature increases by approximately 125°C above ambient. Derating begins above 25°C at 1.8 mW/°C.
Does SZMMBZ5259BLT1G have an internal connection on pin 2?
No, pin 2 of SZMMBZ5259BLT1G is a no-connect (NC) terminal - it is not bonded internally and must remain electrically floating on the PCB. The device uses only pins 1 (anode) and 3 (cathode) for operation. This NC configuration is confirmed in the marking diagram and mechanical outline documentation for Style 8 SOT-23 packages, and misconnecting pin 2 may compromise reliability or cause assembly defects.
What is the maximum leakage current specification for SZMMBZ5259BLT1G?
The maximum reverse leakage current (IR) for SZMMBZ5259BLT1G is 0.1 μA at VR = 30 V and TA = 25°C. This ultra-low leakage ensures minimal parasitic current draw in standby or undervoltage conditions - critical for battery-powered systems such as wearables and remote sensors where microamp-level currents directly impact operational lifetime. Leakage remains within specification across the full −65°C to +150°C temperature range.
SZMMBZ5259BLT1G 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):
- 39 V
- Tolerance:
- ±5%
- Power - Max:
- 225 mW
- Impedance (Max) (Zzt):
- 80 Ohms
- Current - Reverse Leakage @ Vr:
- 100 nA @ 30 V
- Voltage - Forward (Vf) (Max) @ If:
- 900 mV @ 10 mA
- Operating Temperature:
- -65°C ~ 150°C
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-3 (TO-236)
SZMMBZ5259BLT1G FAQ
1.How can I place an order for SZMMBZ5259BLT1G through Aetrix?
Please submit a Request for Quotation (RFQ) for SZMMBZ5259BLT1G 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 SZMMBZ5259BLT1G reliable?
The price and inventory of SZMMBZ5259BLT1G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SZMMBZ5259BLT1G is usually 5 days.
3.What payment methods are accepted for SZMMBZ5259BLT1G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SZMMBZ5259BLT1G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SZMMBZ5259BLT1G?
SZMMBZ5259BLT1G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SZMMBZ5259BLT1G 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 SZMMBZ5259BLT1G?
For technical support, including SZMMBZ5259BLT1G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SZMMBZ5259BLT1G requirements.
6.How does Aetrix verify that SZMMBZ5259BLT1G is sourced from the original manufacturer or authorized distributors?
All SZMMBZ5259BLT1G 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 SZMMBZ5259BLT1G meets industry standards.
7.What is the process for return or replacement of SZMMBZ5259BLT1G?
All SZMMBZ5259BLT1G units undergo pre-shipment inspection (PSI). If there is an issue with SZMMBZ5259BLT1G, 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 SZMMBZ5259BLT1G part is unused and in its original packaging.
Return procedure for SZMMBZ5259BLT1G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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