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Diodes Incorporated MMBZ5257BT-7-F
- Part No.:
- MMBZ5257BT-7-F
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Zener Diodes
- Package:
- SOT-523
- Datasheet:
-
MMBZ5257BT-7-F.pdf
- Description:
- DIODE ZENER 33V 150MW SOT523
- Quantity:
- Payment:
- Shipping:
Inventory:3,044
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Product details
Overview
MMBZ5257BT-7-F from Diodes Incorporated is a 33 V, 150 mW surface-mount Zener diode in SOT-523 package, with nominal zener voltage 33 V (min 31.35 V, max 34.65 V), test current 3.8 mA, dynamic impedance 58 Ω at 1 kHz, and reverse leakage ≤0.1 μA at 25 V, used for precision voltage regulation and reference in low-power sensor interfaces and portable power management circuits.
For engineers reviewing the MMBZ5257BT-7-F datasheet, MMBZ5257BT-7-F pinout, MMBZ5257BT-7-F application, or MMBZ5257BT-7-F equivalent, key selection criteria include zener voltage tolerance, dynamic impedance at specified test current, power derating behavior above 25°C, and SOT-523 thermal resistance (833 °C/W) for compact PCB layouts.
Technical Context
This Zener diode operates in reverse breakdown mode to maintain stable voltage across its terminals under varying load or supply conditions. Its planar die construction ensures consistent breakdown characteristics and low leakage, while the ultra-small SOT-523 footprint supports high-density automated assembly on space-constrained boards.
It delivers regulated output with ±3.5% voltage tolerance (31.35–34.65 V), exhibits 58 Ω dynamic impedance at 3.8 mA test current and 1 kHz, and maintains ≤0.1 μA reverse leakage at VR = 25 V - enabling reliable reference performance in battery-powered analog front-ends and voltage-monitoring circuits.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (Nom) | 33 V - precise regulation point for 3.3 V rail monitoring or 33 V bias generation |
| Zener Voltage Range | 31.35 V to 34.65 V - ±3.5% tolerance defines worst-case error in reference applications |
| Test Current (IZT) | 3.8 mA - operating point where voltage and impedance are specified; sets minimum bias requirement |
| Zener Impedance (ZZT) | 58 Ω at 1 kHz - determines AC regulation stability under dynamic load transients |
| Power Dissipation | 150 mW at 25°C - limits maximum continuous current to ~4.5 mA at 33 V before thermal derating |
| Reverse Leakage (IR) | ≤0.1 μA at 25 V - ensures negligible quiescent current draw in always-on sensing nodes |
| Thermal Resistance (RθJA) | 833 °C/W - requires careful pad layout per AP02001 to avoid exceeding 150°C junction temperature |
Pinout & Package
Package: SOT-523 - ultra-compact 3-terminal surface-mount plastic package (1.6 mm × 0.8 mm × 0.5 mm), UL 94V-0 rated, lead-free and RoHS compliant, optimized for pick-and-place assembly.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (A) | Forward conduction terminal / cathode reference ground path | Connected to system ground or lower-potential node when used in shunt regulation |
| Cathode (K) | Zener breakdown terminal / voltage reference output | Connected to regulated node; voltage develops across K-to-A during reverse bias |
| Case / Not Connected | Non-electrical mechanical termination | SOT-523 has no internal thermal pad; case is electrically isolated and non-functional |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-small SOT-523 footprint | Enables placement in <1.0 mm² board area - critical for wearables and hearing aids |
| Planar die construction | Ensures tight voltage distribution and repeatable Zener knee characteristics across production lots |
| 150 mW power rating with defined derating curve | Supports predictable thermal design up to +125°C ambient using standard FR-4 layout |
| Lead-free and RoHS-compliant plating | Matte tin finish over Alloy 42 leadframe meets IPC-J-STD-020D Level 1 moisture sensitivity |
Applications
| Battery Voltage Monitor | Low-Power Sensor Reference |
|---|---|
Use Scenario: Monitoring Li-ion cell voltage in portable medical devices to trigger low-battery alerts. IC Role / Device Role / Timing Role: Shunt Zener reference providing stable 33 V threshold for comparator input. Use Value: 0.1 μA leakage ensures <1 nA loading on high-impedance divider, preserving battery life over multi-year operation. | Use Scenario: Supplying precision bias to MEMS pressure sensor amplifier in IoT environmental nodes. IC Role / Device Role / Timing Role: Voltage reference source establishing fixed gain-setting point for instrumentation amplifier. Use Value: ±3.5% voltage tolerance and 58 Ω impedance enable sub-0.5% full-scale error in 12-bit ADC systems. |
| USB-C Power Negotiation Clamp | Industrial PLC Input Protection |
Use Scenario: Clamping CC line voltage during USB-C port detection to prevent false connection signals. IC Role / Device Role / Timing Role: Overvoltage clamp limiting CC pin to 33 V during hot-plug transients. Use Value: Fast Zener turn-on (ns-scale) and 150 mW surge capability absorb 100 ns/1 A pulses without degradation. | Use Scenario: Protecting 24 V digital input channels in factory automation controllers from field-wiring surges. IC Role / Device Role / Timing Role: Primary shunt regulator absorbing transient energy before TVS activation. Use Value: Low 58 Ω impedance ensures clamping voltage stays within 33.5 V during 100 mA fault currents. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX584-C33 | Same 33 V nominal, but SOD-523 package (slightly larger); 100 mW rating; 90 Ω Zzt | Higher impedance reduces regulation accuracy in precision references | Prefer for cost-sensitive industrial controls where ±5% voltage tolerance is acceptable |
| MMSZ5257T1G | Same 33 V nominal, SOD-123 package; 500 mW rating; 35 Ω Zzt; higher leakage (1.0 μA) | Larger footprint and higher leakage limit use in ultra-low-power designs | Choose when higher surge robustness is required and board space permits SOD-123 |
Compared with BZX584-C33 and MMSZ5257T1G, MMBZ5257BT-7-F offers the smallest footprint and lowest leakage among 33 V Zeners, making it optimal for space- and current-constrained applications - though its 58 Ω impedance sits between the two alternatives' values.
Availability
MMBZ5257BT-7-F is available at Aetrix Electronics and suitable for battery voltage monitoring, low-power sensor reference, USB-C clamp circuits, and industrial PLC input protection requiring stable component supply and long-term manufacturability.
Supply support for MMBZ5257BT-7-F 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, serving automotive, industrial, computing, and consumer markets with a focus on reliability and efficiency.
This device belongs to the MMBZ52xxBT series of ultra-miniature Zener diodes designed specifically for high-volume, space-constrained applications demanding consistent voltage regulation and automated assembly compatibility.
FAQ
What is the maximum reverse voltage this Zener can withstand before breakdown?
The MMBZ5257BT-7-F has a nominal zener voltage of 33 V with a guaranteed range of 31.35 V to 34.65 V at 3.8 mA test current. Below 31.35 V, it remains in high-impedance reverse-blocking state with ≤0.1 μA leakage at 25 V - no hard "maximum reverse voltage" beyond breakdown is specified, as operation is intended in controlled breakdown.
Can this part be used in place of a 30 V Zener in an existing design?
No - the MMBZ5257BT-7-F is a 33 V device (31.35–34.65 V range), not 30 V. Substituting it for a 30 V Zener (e.g., MMBZ5256BT) would raise the regulation threshold by ~3 V, potentially causing overvoltage in downstream circuitry or incorrect trip points in monitoring functions.
Does this Zener diode require a series current-limiting resistor in all applications?
Yes - as a shunt regulator, it must be paired with a series resistor to limit current through the diode to stay within its 150 mW power rating. For 33 V operation at 25°C, maximum continuous current is ~4.5 mA; exceeding this risks thermal runaway or parametric shift without proper biasing.
Is the SOT-523 package compatible with standard reflow profiles for lead-free soldering?
Yes - the MMBZ5257BT-7-F uses matte tin plating over Alloy 42 and complies with J-STD-020D Level 1 moisture sensitivity. It supports standard Pb-free reflow profiles (peak 260°C, 60 seconds max), provided board layout follows Diodes Inc.'s recommended pad dimensions in AP02001.
MMBZ5257BT-7-F Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Series:
- -
- Package/Case:
- SOT-523
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 33 V
- Tolerance:
- ±5%
- Power - Max:
- 150 mW
- Impedance (Max) (Zzt):
- 58 Ohms
- Current - Reverse Leakage @ Vr:
- 100 nA @ 25 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:
- SOT-523
MMBZ5257BT-7-F FAQ
1.How can I place an order for MMBZ5257BT-7-F through Aetrix?
Please submit a Request for Quotation (RFQ) for MMBZ5257BT-7-F 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 MMBZ5257BT-7-F reliable?
The price and inventory of MMBZ5257BT-7-F are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMBZ5257BT-7-F is usually 5 days.
3.What payment methods are accepted for MMBZ5257BT-7-F?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMBZ5257BT-7-F transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MMBZ5257BT-7-F?
MMBZ5257BT-7-F orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MMBZ5257BT-7-F 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 MMBZ5257BT-7-F?
For technical support, including MMBZ5257BT-7-F datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMBZ5257BT-7-F requirements.
6.How does Aetrix verify that MMBZ5257BT-7-F is sourced from the original manufacturer or authorized distributors?
All MMBZ5257BT-7-F 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 MMBZ5257BT-7-F meets industry standards.
7.What is the process for return or replacement of MMBZ5257BT-7-F?
All MMBZ5257BT-7-F units undergo pre-shipment inspection (PSI). If there is an issue with MMBZ5257BT-7-F, 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 MMBZ5257BT-7-F part is unused and in its original packaging.
Return procedure for MMBZ5257BT-7-F:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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