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onsemi MMBZ5248B
- Part No.:
- MMBZ5248B
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
MMBZ5248B.pdf
- Description:
- DIODE ZENER 18V 350MW SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:8,131
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Product details
Overview
MMBZ5248B from Fairchild Semiconductor is a 18 V, 5% tolerance Zener diode in SOT-23 package, rated for 350 mW power dissipation, with 21 Ω dynamic impedance at 5 mA test current and 0.25 µA reverse leakage at 14.4 V, used for precision voltage regulation and overvoltage protection in low-power analog circuits.
For engineers reviewing the MMBZ5248B datasheet, pinout, applications, or equivalent options, key selection criteria include Zener voltage tolerance, dynamic impedance at specified test current, reverse leakage at rated VR, thermal stability across -55°C to +150°C, and SOT-23 footprint compatibility with space-constrained PCB layouts.
Technical Context
The MMBZ5248B operates as a silicon planar Zener diode optimized for stable voltage reference and clamping functions in DC bias networks and feedback paths. It exhibits a nominal Zener voltage of 18 V with ±5% tolerance, 21 Ω dynamic impedance (ZZ) measured at IZ = 5 mA, and maintains <0.25 µA reverse leakage current at VR = 14.4 V.
Its thermal performance is defined by a maximum junction temperature of +150°C and storage range from –55°C to +150°C. Forward voltage is capped at 0.9 V at IF = 10 mA, supporting bidirectional transient suppression when paired with complementary devices.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 18 V ±5% - defines precise clamping threshold for 15–21 V operating window |
| Dynamic Impedance (ZZ) | 21 Ω @ IZ = 5 mA - determines regulation stiffness under load variation |
| Reverse Leakage (IR) | 0.25 µA @ VR = 14.4 V - ensures minimal quiescent current in standby mode |
| Power Dissipation (PD) | 350 mW - sets maximum continuous power handling in SOT-23 package |
| Forward Voltage (VF) | ≤0.9 V @ IF = 10 mA - enables use in low-voltage bidirectional ESD clamp configurations |
| Junction Temperature (TJ) | +150°C max - supports operation in high-ambient industrial environments |
Pinout & Package
MMBZ5248B is housed in a standard SOT-23 surface-mount package with three terminals: anode (Pin 1), cathode (Pin 2), and no-connect (Pin 3). Pin 3 is internally unconnected and must remain floating per datasheet connection diagram.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 | Anode | Connects to lower-potential node in reverse-bias Zener configuration |
| Pin 2 | Cathode | Connects to higher-potential node; polarity mark on package aligns with this terminal |
| Pin 3 | No-connect (NC) | Internally isolated; must not be soldered or tied to any net |
Key Features
| Feature | Design Value |
|---|---|
| ±5% Zener voltage tolerance | Enables predictable clamping without post-production trimming in cost-sensitive designs |
| Low dynamic impedance (21 Ω) | Maintains tight output voltage regulation under varying load currents up to 5 mA |
| SOT-23 footprint | Supports automated placement and reflow in high-density consumer and portable electronics |
| 150°C junction rating | Allows reliable operation in thermally constrained enclosures without derating below 350 mW |
Applications
| Power Supply Reference | Overvoltage Clamp |
|---|---|
Use Scenario: Stabilizing feedback voltage in low-current linear regulators or op-amp reference nodes. IC Role / Device Role / Timing Role: Zener diode providing fixed 18 V reference point for error amplifier input. Use Value: Delivers stable regulation with <0.25 µA leakage, minimizing offset drift in precision analog stages. | Use Scenario: Protecting microcontroller I/O pins from transient overvoltage events. IC Role / Device Role / Timing Role: Shunt clamping device diverting surge current above 18 V to ground. Use Value: Limits voltage excursion to ≤18.9 V (5% tolerance) while dissipating <350 mW during transient. |
| Signal Level Translation | Battery Voltage Monitor |
Use Scenario: Biasing logic-level shifters between 3.3 V and 5 V domains using passive resistor-Zener networks. IC Role / Device Role / Timing Role: Voltage-limited sink in level-shifting divider network. Use Value: Ensures output never exceeds 18 V, preventing damage to downstream 5 V tolerant inputs. | Use Scenario: Monitoring 12 V lead-acid battery health via ADC input with scaled-down voltage. IC Role / Device Role / Timing Role: Precision 18 V reference in resistive divider for accurate full-scale calibration. Use Value: Enables ±0.9 V absolute accuracy in battery voltage reporting over temperature. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1SMA5927BT3G | 18 V, ±5%, 1.5 W power rating, DO-214AC package | Higher power handling but larger footprint; unsuitable for SOT-23-only layouts | Select when >350 mW surge energy absorption is required and board space permits DO-214AC |
| BZX84-C18 | 18 V, ±5%, 300 mW, SOT-23 package, 40 Ω ZZ @ 5 mA | Higher dynamic impedance reduces regulation accuracy under load variation | Choose for cost-sensitive designs where ±5% VZ suffices and tighter impedance is not critical |
Compared with 1SMA5927BT3G and BZX84-C18, the MMBZ5248B offers optimal balance of SOT-23 compatibility, 21 Ω low-impedance regulation, and 350 mW rating-making it preferred for compact, precision-clamp applications where thermal and spatial constraints exclude higher-power or higher-impedance alternatives.
Availability
MMBZ5248B is available at Aetrix Electronics and suitable for voltage reference, overvoltage protection, and signal-level translation requiring stable component supply in consumer, industrial control, and automotive body electronics.
Supply support for MMBZ5248B 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.
The MMBZ52xxB series was designed for general-purpose voltage regulation and transient suppression in space-constrained, low-power electronic systems where SOT-23 packaging and tight Zener tolerance were essential.
FAQ
What is the Zener voltage tolerance of MMBZ5248B?
The MMBZ5248B has a Zener voltage tolerance of ±5% at 18 V, meaning its actual breakdown voltage falls within 17.1 V to 18.9 V under standard test conditions (TA = 25°C, IZ = 5 mA). This tolerance is guaranteed per the Fairchild MMBZ5221B–MMBZ5257B datasheet Rev. A2 and applies across the full operating temperature range.
What is the maximum power dissipation rating for MMBZ5248B?
The MMBZ5248B is rated for 350 mW maximum power dissipation at TA = 25°C in free air. Derating is required above 25°C ambient, following the specified thermal resistance curve. This rating assumes proper PCB copper area for heat sinking and is validated per the Absolute Maximum Ratings table in the original Fairchild datasheet.
Does MMBZ5248B have a no-connect pin, and how should it be handled?
Yes, MMBZ5248B has Pin 3 designated as no-connect (NC) per the official connection diagram. It is internally unconnected and must remain electrically floating-never tied to ground, VCC, or any other net. Soldering or routing to Pin 3 may compromise device reliability or cause unpredictable behavior.
What is the forward voltage specification for MMBZ5248B?
The forward voltage (VF) of MMBZ5248B is specified as ≤0.9 V at IF = 10 mA, consistent across the entire MMBZ5200 series. This parameter supports dual-use in low-voltage clamping circuits and confirms diode functionality during forward-bias verification tests.
How does MMBZ5248B perform at elevated temperatures?
MMBZ5248B maintains operation up to +150°C junction temperature, with Zener voltage exhibiting predictable positive temperature coefficient behavior. The datasheet provides typical VZ vs. temperature curves showing drift of approximately +0.08%/°C near 18 V, enabling accurate compensation in high-temperature reference designs.
MMBZ5248B Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- TO-236-3, SC-59, SOT-23-3
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Voltage - Zener (Nom) (Vz):
- 18 V
- Tolerance:
- ±5%
- Power - Max:
- 350 mW
- Impedance (Max) (Zzt):
- 21 Ohms
- Current - Reverse Leakage @ Vr:
- 100 nA @ 14 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:
- SOT-23-3
MMBZ5248B FAQ
1.How can I place an order for MMBZ5248B through Aetrix?
Please submit a Request for Quotation (RFQ) for MMBZ5248B 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 MMBZ5248B reliable?
The price and inventory of MMBZ5248B are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMBZ5248B is usually 5 days.
3.What payment methods are accepted for MMBZ5248B?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMBZ5248B transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MMBZ5248B?
MMBZ5248B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MMBZ5248B 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 MMBZ5248B?
For technical support, including MMBZ5248B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMBZ5248B requirements.
6.How does Aetrix verify that MMBZ5248B is sourced from the original manufacturer or authorized distributors?
All MMBZ5248B 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 MMBZ5248B meets industry standards.
7.What is the process for return or replacement of MMBZ5248B?
All MMBZ5248B units undergo pre-shipment inspection (PSI). If there is an issue with MMBZ5248B, 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 MMBZ5248B part is unused and in its original packaging.
Return procedure for MMBZ5248B:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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