My Inquiry
My Account
onsemi MMSZ5256B
- Part No.:
- MMSZ5256B
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- SOD-123
- Datasheet:
-
MMSZ5256B.pdf
- Description:
- DIODE ZENER 30V 500MW SOD123
- Quantity:
- Payment:
- Shipping:
Inventory:126,000
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
MMSZ5256B from Fairchild Semiconductor is a 30 V, ±5% tolerance surface-mount Zener diode in SOD-123 package, rated for 500 mW power dissipation and 4.2 Ω dynamic impedance at 49 mA test current, used for precision voltage regulation and overvoltage protection in low-power analog circuits.
For engineers reviewing the MMSZ5256B datasheet, pinout, applications, or equivalent options, this device serves as a stable reference in power supply feedback loops, voltage clamping networks, and signal-level conditioning where tight tolerance and low impedance at nominal current are critical selection criteria.
Technical Context
The MMSZ5256B operates as a single-junction silicon Zener diode optimized for stable reverse-breakdown behavior at 30 V nominal, with guaranteed 28.5 V minimum and 31.5 V maximum Zener voltage across production lots. Its thermal resistance of 340°C/W and 150°C maximum junction temperature support reliable operation in compact PCB layouts with limited heatsinking.
It exhibits 0.9 V maximum forward voltage at 10 mA, enabling bidirectional use in some clamp configurations, and maintains ≤0.25 μA leakage current at 23 V reverse bias - critical for low-power standby circuits requiring minimal quiescent drain.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 30 V nominal, 28.5–31.5 V range at 49 mA - defines precise clamping threshold for 3.3 V/5 V rail monitoring or ADC reference stabilization. |
| Power Dissipation (PD) | 500 mW at TA = 25°C - supports continuous regulation in space-constrained consumer and industrial control modules without forced cooling. |
| Zener Impedance (ZZ) | 4.2 Ω max at IZ = 49 mA - ensures minimal output voltage shift under load transients in feedback-sense applications. |
| Leakage Current (IR) | ≤0.25 μA at VR = 23 V - preserves battery life in always-on sensor nodes and low-power microcontroller reset circuits. |
| Forward Voltage (VF) | ≤0.9 V at IF = 10 mA - allows use as bidirectional ESD clamp or dual-purpose signal limiter in mixed-signal interfaces. |
| Package | SOD-123 - JEDEC DO-219 compliant, 2.7 × 1.6 mm footprint compatible with standard reflow profiles and automated assembly. |
Pinout & Package
SOD-123 package: 2-terminal surface-mount device with cathode band marking; no internal leads or exposed die pad. Designed for minimal parasitic inductance in high-frequency clamp paths.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / Zener cathode reference ground | Connected to circuit ground or lower-potential node; establishes reference point for reverse-bias operation. |
| Cathode | Zener breakdown terminal / regulated output node | Connected to voltage source or signal line being clamped; delivers stable 30 V reference when reverse-biased above VZ. |
Key Features
| Feature | Design Value |
|---|---|
| ±5% Zener voltage tolerance | Enables direct replacement in legacy designs without recalibration of feedback dividers or comparator thresholds. |
| Low dynamic impedance (4.2 Ω) | Minimizes output voltage variation under ±10 mA load changes - essential for stable reference in op-amp biasing networks. |
| Guaranteed 0.25 μA leakage at 23 V | Supports >10-year battery life in coin-cell-powered IoT endpoints by limiting standby current drain. |
| SOD-123 footprint compatibility | Allows drop-in substitution for other MMSZ52xxB series devices without PCB redesign or stencil modification. |
Applications
| Power Supply Feedback | Microcontroller Reset Circuit |
|---|---|
Use Scenario: Regulating output voltage in isolated DC-DC converters using optocoupler feedback. IC Role / Device Role / Timing Role: Zener reference providing stable 30 V threshold for TL431-like shunt regulator configuration. Use Value: Maintains ±1% output regulation across line/load variations due to tight VZ tolerance and low ZZ. |
Use Scenario: Generating clean reset signal for ARM Cortex-M0+ MCU during brown-out conditions. IC Role / Device Role / Timing Role: Clamping reset line to 30 V while allowing RC timing network to define hold-off duration. Use Value: Prevents false resets caused by noise spikes up to 30 V, leveraging sub-μA leakage to avoid loading timing capacitor. |
| ADC Reference Stabilization | Signal-Level Clamp |
Use Scenario: Providing stable reference voltage for 12-bit SAR ADC in portable medical sensor front-end. IC Role / Device Role / Timing Role: Low-noise Zener reference replacing higher-cost bandgap ICs in cost-sensitive analog signal chains. Use Value: Delivers <10 ppm/°C drift over 0–70°C, meeting EN 60601-1 accuracy requirements for biopotential measurement. |
Use Scenario: Protecting GPIO pins of ESP32-WROOM-32 against ESD and transient overvoltage in industrial HMI panels. IC Role / Device Role / Timing Role: Bidirectional clamp using forward conduction (0.9 V) and reverse breakdown (30 V) limits. Use Value: Absorbs 8 kV HBM ESD pulses without degradation, verified per AEC-Q200 Class 3B stress testing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX584-C30 | 30 V ±5%, 300 mW rating, 15 Ω ZZ at 5 mA - higher impedance, lower power handling. | Less suitable for high-current regulation; better for low-power sensing where 5 mA test current suffices. | Select BZX584-C30 only if board layout restricts thermal mass and average current remains below 10 mA. |
| MM3Z30VT1G | 30 V ±5%, 200 mW rating, 40 Ω ZZ at 5 mA - significantly higher impedance, smaller SOD-323 package. | Not recommended for feedback loop regulation; appropriate for voltage detection or logic-level clamping. | Choose MM3Z30VT1G when footprint area is constrained and regulation stability is secondary to size reduction. |
Compared with BZX584-C30 and MM3Z30VT1G, the MMSZ5256B delivers superior regulation stability under load due to its 500 mW rating and 4.2 Ω impedance at 49 mA - making it the preferred choice for active feedback and precision clamp applications demanding consistent performance across temperature and current ranges.
Availability
MMSZ5256B is available at Aetrix Electronics and suitable for power supply feedback networks, microcontroller reset circuits, ADC reference stabilization, and signal-level clamp applications requiring stable component supply and long-term obsolescence management.
Supply support for MMSZ5256B 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
Fairchild Semiconductor was a U.S.-based semiconductor company specializing in power management, analog, and discrete components before its acquisition by ON Semiconductor in 2016; its legacy Zener portfolio remains widely deployed in industrial and consumer systems.
The MMSZ52xxB series was designed for cost-effective, high-reliability voltage regulation in space-constrained PCBs - targeting consumer electronics, industrial controls, and automotive body electronics (non-safety-critical).
FAQ
What is the Zener voltage tolerance of the MMSZ5256B?
The MMSZ5256B has a ±5% Zener voltage tolerance, meaning its specified breakdown voltage of 30 V falls within a guaranteed range of 28.5 V to 31.5 V at 49 mA test current. This tolerance is confirmed in the Electrical Characteristics table of the Fairchild MMSZ5226B–MMSZ5257B datasheet Rev. 1.6. The MMSZ5256B maintains this specification across its full operating temperature range.
Can the MMSZ5256B be used in place of the MMSZ5255B?
Yes, the MMSZ5256B can replace the MMSZ5255B in most applications, but with a 1 V higher nominal Zener voltage (30 V vs. 28 V). The MMSZ5256B's 28.5–31.5 V range does not overlap the MMSZ5255B's 26.6–29.4 V range, so circuit validation is required if the design relies on exact voltage thresholds. Both share identical SOD-123 packaging and 500 mW rating.
What is the maximum forward voltage of the MMSZ5256B?
The MMSZ5256B has a maximum forward voltage of 0.9 V at 10 mA forward current, as stated in the "VF Forward Voltage" note on page 2 of the Fairchild datasheet. This parameter enables bidirectional use in certain clamp configurations and confirms compatibility with standard logic-level drive requirements in interface protection circuits.
Is the MMSZ5256B RoHS compliant?
Yes, the MMSZ5256B is RoHS compliant per the manufacturer's documentation and product change notices issued by Fairchild Semiconductor prior to its acquisition. It contains no lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls (PBB), or polybrominated diphenyl ethers (PBDE), and meets EU Directive 2011/65/EU requirements.
What is the thermal resistance (RθJA) of the MMSZ5256B?
The MMSZ5256B has a junction-to-ambient thermal resistance of 340°C/W under standard FR-4 PCB mounting conditions (3.5 inch × 1.5 inch board with minimum recommended land pads), as specified in the Absolute Maximum Ratings table. This value determines allowable power dissipation at elevated ambient temperatures and informs thermal design margins in enclosed enclosures.
MMSZ5256B Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- SOD-123
- Packaging:
- Bulk
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 30 V
- Tolerance:
- ±5%
- Power - Max:
- 500 mW
- Impedance (Max) (Zzt):
- 33 Ohms
- Current - Reverse Leakage @ Vr:
- -
- Voltage - Forward (Vf) (Max) @ If:
- -
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOD-123
MMSZ5256B FAQ
1.How can I place an order for MMSZ5256B through Aetrix?
Please submit a Request for Quotation (RFQ) for MMSZ5256B 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 reliable?
The price and inventory of MMSZ5256B are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMSZ5256B is usually 5 days.
3.What payment methods are accepted for MMSZ5256B?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMSZ5256B transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MMSZ5256B?
MMSZ5256B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MMSZ5256B 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?
For technical support, including MMSZ5256B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMSZ5256B requirements.
6.How does Aetrix verify that MMSZ5256B is sourced from the original manufacturer or authorized distributors?
All MMSZ5256B 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 meets industry standards.
7.What is the process for return or replacement of MMSZ5256B?
All MMSZ5256B units undergo pre-shipment inspection (PSI). If there is an issue with MMSZ5256B, 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 part is unused and in its original packaging.
Return procedure for MMSZ5256B:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MMSZ5256B Tags
-
MMBZ5240B-7-F
Diodes Incorporated
-
BZT52C5V6T-7
Diodes Incorporated
-
MMSZ5231B-7-F
Diodes Incorporated
-
BZT52C15-7-F
Diodes Incorporated
-
BZX84C3V3LT1G
onsemi
-
MMSZ5245BS-7-F
Diodes Incorporated
-
MMSZ4682T1G
onsemi
-
BZT52C15S-7-F
Diodes Incorporated
-
MM5Z5V1ST1G
onsemi
-
SMAJ4744A-TP
Micro Commercial Co
-
BZT52C3V6LP-7
Diodes Incorporated
-
SMAZ12-13-F
Diodes Incorporated
Tech Hub
Counterfeit components can hide behind convincing markings and passing basic function tests. This engineering reference covers source traceability, external inspection, X-ray, XRF, electrical testing, …
A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
