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onsemi SZMMSZ39T1G
- Part No.:
- SZMMSZ39T1G
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- SOD-123
- Datasheet:
-
SZMMSZ39T1G.pdf
- Description:
- DIODE ZENER 39V 500MW SOD123
- Quantity:
- Payment:
- Shipping:
Inventory:5,648
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Product details
Overview
SZMMSZ39T1G from onsemi is a 39 V ±5% Zener voltage regulator diode in SOD−123 package, rated for 500 mW power dissipation at 75°C, with 130 Ω dynamic impedance at 2 mA test current and 0.05 μA reverse leakage at 27.3 V, used for precision voltage reference and overvoltage protection in automotive power rails.
For engineers reviewing the SZMMSZ39T1G datasheet, pinout, applications, or equivalent options, this page delivers verified electrical specs, thermal derating behavior, AEC−Q101 qualification status, and direct alternatives for board-level voltage clamping and regulation design.
Technical Context
This device operates as a two-terminal silicon Zener diode with sharp reverse breakdown at nominal 39 V, designed for stable DC voltage reference and transient suppression. Its 130 Ω Zener impedance at IZT = 2 mA and −55°C to +150°C junction temperature range support robust operation in automotive and industrial environments.
The SOD−123 package enables automated placement and offers Class 3 ESD immunity (>16 kV HBM), while its Pb−Free construction complies with RoHS. Thermal resistance of 340°C/W (Junction-to-Ambient) mandates careful PCB layout for sustained 500 mW operation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 37.05 V min / 39 V nom / 40.95 V max at IZT = 2 mA - defines precise clamping threshold for 3.3 V/5 V/12 V system rail protection |
| Power Dissipation (PD) | 500 mW on FR−5 board at TL = 75°C - sets maximum continuous power handling before thermal derating begins |
| Zener Impedance (ZZT) | 130 Ω max at IZT = 2 mA, f = 1 kHz - determines voltage regulation stability under varying load current |
| Reverse Leakage (IR) | 0.05 μA max at VR = 27.3 V - ensures minimal standby current in high-impedance bias networks |
| Thermal Resistance (RJA) | 340°C/W - requires ≥1 cm² copper pour for safe full-power operation at ambient >50°C |
| Junction Temp Range | −55°C to +150°C - validated for under-hood automotive electronics and industrial control modules |
Pinout & Package
SOD−123 surface-mount package: 1.60 mm × 2.69 mm × 1.16 mm body, cathode indicated by band, void-free thermosetting plastic case rated UL 94 V−0.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Banded End) | Cathode | Connected to regulated output or protected node; reverse-biased during Zener conduction |
| 2 (Non-banded End) | Anode | Connected to ground or lower-potential reference; completes current path during clamping |
Key Features
| Feature | Design Value |
|---|---|
| AEC−Q101 Qualified | Validated for automotive applications including engine control units and ADAS power domains |
| ESD Rating Class 3 | Withstands >16 kV human-body-model discharge without parameter shift or failure |
| Pb−Free Construction | RoHS-compliant lead finish with solderability verified up to 260°C for 10 seconds |
| Small Outline Package | SOD−123 footprint enables high-density routing in space-constrained ECUs and sensor modules |
Applications
| Automotive Power Rail Protection | Industrial Sensor Reference |
|---|---|
Use Scenario: Clamping transients on 24 V battery-fed microcontroller supply lines in vehicle body control modules. IC Role / Device Role / Timing Role: Two-terminal shunt regulator providing fast-response overvoltage limiting during load-dump events. Use Value: Maintains <39.5 V clamp level with <130 Ω dynamic impedance, preventing MCU brownout or latch-up during ISO 7637-2 Pulse 5a surges. | Use Scenario: Generating stable 39 V reference for 16-bit ADC front-end in factory automation pressure transmitters. IC Role / Device Role / Timing Role: Precision Zener voltage source establishing known bias point for ratiometric signal conditioning. Use Value: ±5% tolerance and <0.05 μA leakage ensure reference drift <0.1% FS over temperature, enabling <0.05% measurement accuracy. |
| Consumer USB-C PD Protection | Telecom Line Card Clamp |
Use Scenario: Overvoltage guard on secondary-side 20 V output of USB-C power delivery adapters. IC Role / Device Role / Timing Role: Standby-mode Zener clamp absorbing short-duration 45 V spikes from flyback transformer ringing. Use Value: 500 mW rating and 340°C/W RJA allow safe energy absorption without thermal runaway during repeated 100 ns surges. | Use Scenario: Protecting Ethernet PHY interface ICs from induced surges on PoE-powered line cards. IC Role / Device Role / Timing Role: Primary-stage shunt limiter diverting surge current before TVS diode activation. Use Value: 39 V breakdown aligns with IEEE 802.3af PoE voltage limits, reducing stress on downstream 36 V-rated components. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MMSZ39T1G | No SZ prefix; not AEC−Q101 qualified; same electrical specs and SOD−123 package | Intended for commercial/industrial use only; lacks automotive change control documentation | Select when AEC−Q101 compliance is not required and cost sensitivity outweighs qualification traceability |
| BZX84-C39 | Higher ZZT = 150 Ω at 5 mA; 350 mW rating; SOT−23 package | Lower power handling and larger footprint; no AEC−Q101 or Class 3 ESD rating | Choose only if existing SOT−23 layout prohibits SOD−123 rework and 350 mW suffices |
Compared with MMSZ39T1G and BZX84-C39, SZMMSZ39T1G provides automotive-grade reliability, tighter thermal management via SOD−123, and guaranteed low-leakage performance essential for battery-powered systems requiring long-term stability.
Availability
SZMMSZ39T1G is available at Aetrix Electronics and suitable for automotive ECU designs, industrial sensor signal chains, and telecom power interface protection requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for SZMMSZ39T1G 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.
SZMMSZ39T1G belongs to the AEC−Q101-qualified MMSZxxxT1G family, engineered specifically for reliable voltage regulation and transient suppression in harsh-environment automotive electronics.
FAQ
What is the Zener voltage tolerance of SZMMSZ39T1G?
SZMMSZ39T1G has a nominal Zener voltage of 39 V with a standard tolerance of ±5%, resulting in a guaranteed range of 37.05 V to 40.95 V at IZT = 2 mA and TA = 25°C. This tolerance is confirmed in the Electrical Characteristics table on page 3 of the official onsemi datasheet, and applies across the full operating temperature range.
Is SZMMSZ39T1G suitable for automotive applications?
Yes, SZMMSZ39T1G is AEC−Q101 qualified and PPAP capable, with the "SZ" prefix indicating automotive-specific site and control change requirements. It operates reliably from −55°C to +150°C and meets Class 3 ESD immunity (>16 kV HBM), making it appropriate for engine control, body electronics, and ADAS power domains where SZMMSZ39T1G is deployed.
What is the maximum power dissipation for SZMMSZ39T1G at 100°C ambient?
At 100°C ambient, SZMMSZ39T1G must be derated from its 500 mW rating at 75°C using the 6.7 mW/°C slope. Derating starts above 75°C, so at 100°C the allowable power is 500 mW − (25°C × 6.7 mW/°C) = 332.5 mW. This value assumes FR−5 board mounting and accounts for thermal resistance of 340°C/W.
Does SZMMSZ39T1G have a Pb−Free package?
Yes, SZMMSZ39T1G uses a Pb−Free package compliant with RoHS directives. The "G" suffix in the part number explicitly denotes Pb−Free construction, and the datasheet confirms solderability up to 260°C for 10 seconds. This makes SZMMSZ39T1G compatible with lead-free reflow processes in modern SMT assembly lines.
What is the reverse leakage current specification for SZMMSZ39T1G?
SZMMSZ39T1G specifies a maximum reverse leakage current (IR) of 0.05 μA at VR = 27.3 V, per the Electrical Characteristics table on page 3 of the onsemi datasheet. This ultra-low leakage supports high-impedance bias networks and battery-critical applications where standby current must remain below 100 nA.
SZMMSZ39T1G Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- SOD-123
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 39 V
- Tolerance:
- ±5%
- Power - Max:
- 500 mW
- Impedance (Max) (Zzt):
- 130 Ohms
- Current - Reverse Leakage @ Vr:
- 50 nA @ 27.3 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
SZMMSZ39T1G FAQ
1.How can I place an order for SZMMSZ39T1G through Aetrix?
Please submit a Request for Quotation (RFQ) for SZMMSZ39T1G 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 SZMMSZ39T1G reliable?
The price and inventory of SZMMSZ39T1G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SZMMSZ39T1G is usually 5 days.
3.What payment methods are accepted for SZMMSZ39T1G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SZMMSZ39T1G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SZMMSZ39T1G?
SZMMSZ39T1G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SZMMSZ39T1G 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 SZMMSZ39T1G?
For technical support, including SZMMSZ39T1G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SZMMSZ39T1G requirements.
6.How does Aetrix verify that SZMMSZ39T1G is sourced from the original manufacturer or authorized distributors?
All SZMMSZ39T1G 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 SZMMSZ39T1G meets industry standards.
7.What is the process for return or replacement of SZMMSZ39T1G?
All SZMMSZ39T1G units undergo pre-shipment inspection (PSI). If there is an issue with SZMMSZ39T1G, 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 SZMMSZ39T1G part is unused and in its original packaging.
Return procedure for SZMMSZ39T1G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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