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onsemi MMSZ18ET1
- Part No.:
- MMSZ18ET1
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- SOD-123
- Datasheet:
-
MMSZ18ET1.pdf
- Description:
- DIODE ZENER 18V 500MW SOD123
- Quantity:
- Payment:
- Shipping:
Inventory:5,999
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Product details
Overview
MMSZ18ET1 from onsemi is a 18 V, ±5% tolerance Zener diode in SOD-123 package, rated for 500 mW power dissipation at 75 °C on FR-5 board, with 45 Ω dynamic impedance at 5 mA test current and 0.05 µA reverse leakage at 12.6 V, used for precision voltage regulation and overvoltage protection in low-power analog circuits.
For engineers reviewing the MMSZ18ET1 datasheet, pinout, applications, or equivalent options, this page delivers verified electrical parameters, thermal derating behavior, cathode/anode terminal mapping, automotive-grade AEC-Q101 qualification status, and direct alternative parts with documented Zener voltage and impedance differences.
Technical Context
This device operates as a two-terminal voltage reference by maintaining a stable reverse breakdown voltage across its terminals under controlled Zener current. It exhibits a positive temperature coefficient near 18 V (≈+3.5 mV/°C), enabling predictable drift compensation in bias networks.
Its 225 W peak surge rating (8 × 20 µs pulse) supports transient suppression in low-energy interfaces, while Class 3 ESD robustness (>16 kV HBM) ensures reliability during automated PCB assembly and field operation in industrial environments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 17.1–18.9 V at IZT = 5 mA; defines regulated output voltage window under nominal bias conditions |
| Dynamic Impedance (ZZT) | 45 Ω max at IZT = 5 mA; determines regulation sensitivity to load current changes |
| Reverse Leakage Current | 0.05 µA max at VR = 12.6 V; ensures minimal quiescent power loss in standby mode |
| Power Dissipation | 500 mW on FR-5 board at TL = 75 °C; sets maximum continuous thermal load before derating begins |
| Junction Temperature Range | −55 °C to +150 °C; enables deployment in automotive engine compartments and industrial control enclosures |
| ESD Rating | Class 3 (>16 kV) per Human Body Model; eliminates need for external ESD protection in handling and assembly |
| AEC-Q101 Qualified | Validated for automotive applications including body electronics and infotainment power rails |
Pinout & Package
Package: SOD-123 surface-mount plastic case (1.60 × 2.69 × 1.16 mm), void-free thermosetting material, UL 94 V-0 flammability rating, cathode indicated by polarity band.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Banded End) | Cathode | Connected to regulated voltage rail; reverse-biased terminal where Zener breakdown occurs |
| 2 (Non-banded End) | Anode | Connected to ground or lower-potential reference; completes bias path for Zener conduction |
Key Features
| Feature | Design Value |
|---|---|
| 500 mW Power Rating | Enables use in higher-current reference and clamp circuits without external heat sinking on standard FR-5 PCBs |
| ±5% Zener Voltage Tolerance | Supports tight voltage thresholding in comparator input stages and ADC reference buffers |
| 150 °C Maximum Junction Temperature | Permits operation in sealed enclosures with limited airflow, such as automotive junction boxes |
| Peak Surge Power: 225 W | Withstands EFT bursts and inductive switching transients in sensor interface and relay driver circuits |
| Pb-Free Construction | Complies with RoHS Directive 2011/65/EU and JEDEC J-STD-020 reflow profile requirements |
Applications
| Industrial Sensor Signal Conditioning | Automotive Body Control Module |
|---|---|
|
Use Scenario: Stabilizing bias voltage for op-amp-based bridge sensor amplifiers in factory-floor pressure transmitters. IC Role / Device Role / Timing Role: Zener reference providing fixed 18 V rail to power instrumentation amplifier and set common-mode level. Use Value: Maintains <±0.5% output stability over −40 °C to +85 °C ambient, reducing calibration drift in 16-bit measurement systems. |
Use Scenario: Overvoltage clamping on LIN bus power supply line feeding door module microcontrollers. IC Role / Device Role / Timing Role: Transient suppressor limiting rail voltage to 18.9 V during load-dump events. Use Value: Absorbs 225 W surge energy without failure, preventing latch-up in 3.3 V LDO regulators downstream. |
| Medical Portable Diagnostic Device | Smart Energy Meter Power Supply |
|
Use Scenario: Providing isolated reference voltage for battery-charged analog front-end in handheld ECG units. IC Role / Device Role / Timing Role: Low-leakage (0.05 µA) Zener establishing precise 18 V reference for ADC full-scale range. Use Value: Enables >14-bit effective resolution by minimizing reference error contribution from diode leakage. |
Use Scenario: Regulating auxiliary 18 V rail for metrology IC and RTC backup in DIN-rail mounted electricity meters. IC Role / Device Role / Timing Role: Primary voltage regulator for non-isolated secondary side, operating continuously at 40 °C ambient. Use Value: Delivers stable 18 V output with <1 % variation across 10-year lifetime, meeting IEC 62053-21 long-term accuracy requirements. |
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-C18LT1G | Zener voltage 17.1–18.9 V (same), but 350 mW rating and 60 Ω ZZT at 5 mA | Lower power handling limits use in high-current reference designs; higher impedance reduces regulation fidelity | Select when cost sensitivity outweighs precision and surge immunity requirements |
| 1N4746A | Through-hole DO-41 package, 1 W rating, 20 Ω ZZT, same 18 V nominal | Requires PCB real estate and wave-solder process; superior thermal performance but incompatible with SMT-only lines | Select only for legacy through-hole designs or where >500 mW continuous dissipation is mandatory |
Compared with BZX84-C18LT1G and 1N4746A, the MMSZ18ET1 offers optimal balance of SMT compatibility, AEC-Q101 qualification, and 225 W surge capability-making it preferred for new automotive and industrial designs requiring compact, robust voltage referencing.
Availability
MMSZ18ET1 is available at Aetrix Electronics and suitable for industrial sensor signal conditioning, automotive body control modules, medical portable diagnostic devices, and smart energy meter power supplies requiring stable component supply and long-term lifecycle assurance.
Supply support for MMSZ18ET1 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.
The MMSZ18ET1 belongs to the MMSZxxxET1G Zener regulator series, engineered for high-reliability, space-constrained voltage reference and protection in automotive and industrial surface-mount systems.
FAQ
What is the Zener voltage tolerance of MMSZ18ET1?
The MMSZ18ET1 has a nominal Zener voltage of 18 V with a standard tolerance of ±5%, resulting in a guaranteed range of 17.1 V to 18.9 V at IZT = 5 mA and TA = 25 °C. This tolerance is specified per onsemi's datasheet revision 8 and applies to all units within the production lot, ensuring consistent voltage setting in precision reference applications.
Is MMSZ18ET1 qualified for automotive use?
Yes, MMSZ18ET1 is AEC-Q101 qualified and PPAP capable, confirming its suitability for automotive applications including body electronics, infotainment power rails, and sensor interfaces. The device meets stress testing requirements for temperature cycling, humidity, mechanical shock, and ESD, making it appropriate for under-hood and cabin-mounted modules.
What is the maximum reverse leakage current for MMSZ18ET1?
The maximum reverse leakage current for MMSZ18ET1 is 0.05 µA at VR = 12.6 V and TA = 25 °C. This ultra-low leakage supports energy-sensitive applications such as battery-powered medical devices and always-on monitoring circuits where standby current must remain below 100 nA.
Can MMSZ18ET1 replace MMSZ18ET1G?
No-MMSZ18ET1 is not a valid part number in onsemi's official documentation; the correct orderable part is MMSZ18ET1G (with 'G' suffix indicating Pb-free construction). MMSZ18ET1G is the only released, active, and supported variant; any reference to MMSZ18ET1 without the 'G' should be verified against onsemi's latest product change notices and ordering guides.
What is the thermal resistance junction-to-ambient for MMSZ18ET1?
The thermal resistance junction-to-ambient (RJA) for MMSZ18ET1 is 340 °C/W, measured via infrared scan method on FR-5 board. This value governs steady-state temperature rise: at 500 mW dissipation, junction temperature rises ~170 °C above ambient, necessitating layout-aware copper pour and ambient derating per Figure 3 in the datasheet.
MMSZ18ET1 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- SOD-123
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Voltage - Zener (Nom) (Vz):
- 18 V
- Tolerance:
- ±5%
- Power - Max:
- 500 mW
- Impedance (Max) (Zzt):
- 45 Ohms
- Current - Reverse Leakage @ Vr:
- 50 nA @ 12.6 V
- Voltage - Forward (Vf) (Max) @ If:
- 900 mV @ 10 mA
- Operating Temperature:
- -55°C ~ 150°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOD-123
MMSZ18ET1 FAQ
1.How can I place an order for MMSZ18ET1 through Aetrix?
Please submit a Request for Quotation (RFQ) for MMSZ18ET1 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 MMSZ18ET1 reliable?
The price and inventory of MMSZ18ET1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMSZ18ET1 is usually 5 days.
3.What payment methods are accepted for MMSZ18ET1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMSZ18ET1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MMSZ18ET1?
MMSZ18ET1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MMSZ18ET1 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 MMSZ18ET1?
For technical support, including MMSZ18ET1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMSZ18ET1 requirements.
6.How does Aetrix verify that MMSZ18ET1 is sourced from the original manufacturer or authorized distributors?
All MMSZ18ET1 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 MMSZ18ET1 meets industry standards.
7.What is the process for return or replacement of MMSZ18ET1?
All MMSZ18ET1 units undergo pre-shipment inspection (PSI). If there is an issue with MMSZ18ET1, 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 MMSZ18ET1 part is unused and in its original packaging.
Return procedure for MMSZ18ET1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MMSZ18ET1 Tags
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