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Diodes Incorporated MMSZ5256B-7
- Part No.:
- MMSZ5256B-7
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Zener Diodes
- Package:
- SOD-123
- Datasheet:
-
MMSZ5256B-7.pdf
- Description:
- DIODE ZENER 30V 500MW SOD123
- Quantity:
- Payment:
- Shipping:
Inventory:7,505
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Product details
Overview
MMSZ5256B-7 from Diodes Incorporated is a 30V, 4.2mA nominal Zener diode in SOD-123 package, rated for 500mW power dissipation at TL=75°C and 370mW at TA=25°C, with 49Ω dynamic impedance at test current and 0.1µA reverse leakage at 23V, widely used for voltage regulation and reference in power supply feedback loops.
For engineers reviewing the MMSZ5256B-7 datasheet, MMSZ5256B-7 pinout, MMSZ5256B-7 application, or MMSZ5256B-7 equivalent, key selection criteria include zener voltage tolerance (±5% at 30V), thermal resistance (338°C/W), cathode-band polarity marking, SOD-123 footprint compatibility, and AEC-Q101 qualification for automotive-grade reliability.
Technical Context
This Zener diode operates in reverse breakdown to maintain stable voltage across load variations and temperature shifts. Its 30V nominal zener voltage exhibits +0.08%/°C temperature coefficient per Figure 6, and it delivers regulated output within ±5% tolerance (28.5–31.5V) under 4.2mA test current.
The device uses alloy-42 leadframe with matte tin plating, supports automated SMT assembly, and meets J-STD-020 moisture sensitivity Level 1. Its 0.01g mass and UL 94V-0 molded plastic case ensure compatibility with high-volume PCB manufacturing and safety-critical layouts.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 30V nominal, 28.5–31.5V range at 4.2mA - defines precise regulation point for feedback networks |
| Power Dissipation (PD) | 370mW at TA=25°C - sets maximum continuous power in ambient PCB conditions |
| Zener Impedance (ZZT) | 49Ω at IZT=4.2mA - determines regulation stiffness and AC ripple rejection |
| Reverse Leakage (IR) | 0.1µA at VR=23V - ensures minimal error current in high-impedance reference paths |
| Thermal Resistance (RθJA) | 338°C/W - quantifies junction-to-ambient heat rise per watt on FR-4 with 1-inch copper pad |
| Package | SOD-123 - surface-mount outline with 2.65mm width, 1.55mm length, 1.05mm height for compact layout |
| AEC-Q101 Qualified | Yes - validated for automotive applications requiring extended temperature (-65°C to +150°C) and reliability |
Pinout & Package
Two-terminal device in SOD-123 package: anode and cathode marked by visible cathode band on top surface; terminals are non-polarized for mounting but functionally asymmetric in circuit operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Reference ground node in shunt regulator configuration | Connected to system ground or lower potential rail; establishes return path for zener current |
| Cathode | Regulated output node | Connected to feedback point or voltage sense line; maintains fixed 30V relative to anode |
Key Features
| Feature | Design Value |
|---|---|
| 500mW power rating at TL=75°C | Enables robust operation in thermally constrained environments without derating below 75°C board temperature |
| Lead-free and halogen-free "Green" compound | Meets RoHS 2 (2011/65/EU) and automotive environmental compliance without compromising flammability (UL 94V-0) |
| Cathode band polarity marking | Ensures unambiguous orientation during automated optical inspection and pick-and-place placement |
| Moisture Sensitivity Level 1 | Eliminates bake requirements prior to reflow, reducing production cycle time and cost |
| Matte tin finish on alloy-42 leadframe | Guarantees solderability per MIL-STD-202 Method 208 and long-term intermetallic stability |
Applications
| Switch-Mode Power Supply Feedback | Automotive ECU Voltage Reference |
|---|---|
Use Scenario: Regulates output voltage in isolated flyback converters via optocoupler feedback loop. IC Role / Device Role / Timing Role: Shunt voltage reference providing stable 30V threshold to TL431-like control ICs. Use Value: Maintains ±1% output accuracy over line/load/temperature with low 0.1µA leakage minimizing bias error. |
Use Scenario: Supplies precision reference for microcontroller ADC calibration in engine control units. IC Role / Device Role / Timing Role: Stable 30V reference source for ratiometric sensor signal conditioning. Use Value: AEC-Q101 qualification ensures operation across -40°C to +125°C ambient with <±0.08%/°C TC. |
| Industrial Sensor Signal Conditioning | Consumer Device Overvoltage Clamp |
Use Scenario: Sets upper limit for 4–20mA transmitter loop voltage in process automation transmitters. IC Role / Device Role / Timing Role: Precision clamp protecting downstream op-amps from transient overvoltage. Use Value: 49Ω ZZT ensures fast response to surges while maintaining tight 30V regulation window. |
Use Scenario: Protects USB-C port VBUS monitoring circuitry against 33V+ transients. IC Role / Device Role / Timing Role: Standby-mode shunt clamp absorbing infrequent overvoltage events. Use Value: 370mW ambient-rated dissipation handles short-duration spikes without thermal runaway. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX584C30 | 30V ±5%, 300mW PD at TA=25°C, SOD-323 package (smaller footprint) | Lower power rating limits use in >10mA regulation paths; smaller size suits space-constrained designs | Select when board area is critical and peak current remains ≤8mA |
| 1N4745A | 30V ±5%, 1W PD, DO-41 through-hole package | Higher power handling but incompatible with SMT-only lines; requires manual or wave-solder step | Select for prototyping or legacy through-hole systems where thermal margin >1W is required |
Compared with BZX584C30 and 1N4745A, MMSZ5256B-7 uniquely balances SMT compatibility, AEC-Q101 qualification, and 370mW ambient-rated power-making it optimal for automotive and industrial surface-mount power management where reliability and manufacturability intersect.
Availability
MMSZ5256B-7 is available at Aetrix Electronics and suitable for automotive ECUs, industrial power supplies, and consumer USB protection circuits requiring stable component supply with full traceability and long-term lifecycle support.
Supply support for MMSZ5256B-7 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
Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, with design and manufacturing operations across Asia and the Americas.
MMSZ5256B-7 belongs to the MMSZ52xxB series of precision Zener diodes engineered for high-reliability voltage reference and regulation in automotive, industrial, and computing power systems.
FAQ
What is the maximum continuous zener current for MMSZ5256B-7 at 25°C ambient?
At TA=25°C, the device is rated for 370mW power dissipation. With a nominal 30V zener voltage, the maximum continuous zener current is approximately 12.3mA (370mW ÷ 30V), assuming no additional thermal resistance beyond the specified RθJA=338°C/W.
Does MMSZ5256B-7 require derating above 25°C ambient temperature?
Yes - the power derating curve (Figure 1) shows linear reduction from 370mW at 25°C to zero at 150°C. Derating factor is 3.7mW/°C above 25°C, meaning at 75°C ambient, maximum allowable power drops to 500mW (as rated at TL=75°C), consistent with its thermal design envelope.
How is polarity identified on the MMSZ5256B-7 SOD-123 package?
Polarity is indicated by a distinct cathode band printed on the top surface of the SOD-123 case, aligned with the cathode terminal. The band corresponds to the shorter lead in through-hole equivalents and must be oriented toward the higher potential node in shunt regulator configurations.
Is MMSZ5256B-7 suitable for use in medical equipment power supplies?
No - Diodes Incorporated explicitly restricts use in life support devices without CEO approval. While the part meets AEC-Q101 and RoHS standards, it lacks ISO 13485 manufacturing certification or specific medical-grade qualification required for implanted or critical-care systems.
MMSZ5256B-7 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Series:
- -
- Package/Case:
- SOD-123
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- 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:
- -65°C ~ 150°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOD-123
MMSZ5256B-7 FAQ
1.How can I place an order for MMSZ5256B-7 through Aetrix?
Please submit a Request for Quotation (RFQ) for MMSZ5256B-7 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 MMSZ5256B-7 reliable?
The price and inventory of MMSZ5256B-7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMSZ5256B-7 is usually 5 days.
3.What payment methods are accepted for MMSZ5256B-7?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMSZ5256B-7 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MMSZ5256B-7?
MMSZ5256B-7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MMSZ5256B-7 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 MMSZ5256B-7?
For technical support, including MMSZ5256B-7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMSZ5256B-7 requirements.
6.How does Aetrix verify that MMSZ5256B-7 is sourced from the original manufacturer or authorized distributors?
All MMSZ5256B-7 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 MMSZ5256B-7 meets industry standards.
7.What is the process for return or replacement of MMSZ5256B-7?
All MMSZ5256B-7 units undergo pre-shipment inspection (PSI). If there is an issue with MMSZ5256B-7, 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 MMSZ5256B-7 part is unused and in its original packaging.
Return procedure for MMSZ5256B-7:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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