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Diodes Incorporated ZMM5257B-7
- Part No.:
- ZMM5257B-7
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Zener Diodes
- Package:
- DO-213AC, MINI-MELF, SOD-80
- Datasheet:
-
ZMM5257B-7.pdf
- Description:
- DIODE ZENER 33V 500MW MINI MELF
- Quantity:
- Payment:
- Shipping:
Inventory:9,144
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Product details
Overview
ZMM5257B-7 from Diodes Incorporated is a 33 V, 500 mW surface-mount Zener diode in MiniMELF (DO-213AA) glass package, rated for 3.8 mA test current, 58 Ω dynamic impedance at 1 mA, and ±0.092 %/°C temperature coefficient. It provides precision voltage regulation in low-power analog reference and overvoltage protection circuits across industrial sensor interfaces and power supply feedback loops.
For engineers reviewing the ZMM5257B-7 datasheet, ZMM5257B-7 pinout, ZMM5257B-7 application, or ZMM5257B-7 equivalent, key selection criteria include its 31.35–34.65 V zener voltage range at 3.8 mA, 700 Ω maximum knee impedance, 0.1 µA reverse leakage at 25 V, and thermal resistance of 300 °C/W - all critical for stable biasing in temperature-varying environments.
Technical Context
This Zener diode operates in reverse breakdown to maintain a stable reference voltage under controlled current conditions. Its hemispherical glass MiniMELF package ensures hermetic sealing and consistent thermal performance, with junction-to-ambient thermal resistance fixed at 300 °C/W when mounted on non-heatsinked PCB pads.
The device exhibits a positive temperature coefficient of +0.092 %/°C above 30 V, enabling predictable drift compensation in multi-stage references. Its 500 mW power rating is valid only when terminals are held at ambient temperature, per Note 1 in the datasheet.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage | 33 V nominal, 31.35–34.65 V range at 3.8 mA - defines regulated output level in shunt regulator designs |
| Power Dissipation | 500 mW at TA = 25°C - sets maximum continuous DC or pulsed power handling without derating |
| Zener Impedance | 58 Ω max at IZT = 3.8 mA; 700 Ω max at IZK = 0.25 mA - determines regulation stiffness under load transients |
| Reverse Leakage | 0.1 µA max at VR = 25 V - ensures minimal error current in high-impedance reference nodes |
| Temp Coefficient | +0.092 %/°C - quantifies voltage drift per degree rise, critical for wide-temperature operation |
| Thermal Resistance | 300 °C/W junction-to-ambient - governs allowable ambient temperature rise at full power |
| Forward Voltage | 1.5 V at IF = 200 mA - relevant for polarity verification and ESD protection path design |
Pinout & Package
MiniMELF (DO-213AA) glass package: cylindrical hermetic body, 3.30–3.70 mm length (A), 1.30–1.60 mm diameter (B), cathode band marking. No discrete pins - two axial solderable terminals.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / Reference ground node in shunt regulator | Connected to circuit common; establishes reference potential when cathode is biased above it |
| Cathode | Reverse breakdown terminal / Regulated output node | Bias input for voltage clamping; delivers stable 33 V when current ≥3.8 mA flows into this terminal |
Key Features
| Feature | Design Value |
|---|---|
| Hermetic glass construction | Ensures long-term parameter stability and moisture immunity in harsh industrial environments |
| Low knee impedance (700 Ω) | Enables usable regulation even at sub-mA currents, supporting ultra-low-power sensor biasing |
| Precision tempco (+0.092 %/°C) | Allows accurate drift modeling for calibration-compensated references across –65°C to +175°C |
| MiniMELF mechanical outline | Provides superior thermal dissipation vs. SOD-123 while maintaining automated placement compatibility |
Applications
| Industrial Sensor Signal Conditioning | USB-C Power Delivery Feedback |
|---|---|
Use Scenario: Stabilizing excitation voltage for 4–20 mA loop-powered pressure transmitters operating from 24 V rails. IC Role / Device Role / Timing Role: Shunt voltage reference providing precise 33 V bias to op-amp input stages and ADC reference dividers. Use Value: Maintains <±1% output accuracy over –40°C to +85°C due to known +0.092 %/°C drift and low 58 Ω dynamic impedance. | Use Scenario: Setting feedback threshold in secondary-side synchronous rectifier controllers for 20 V USB PD PPS profiles. IC Role / Device Role / Timing Role: Precision clamp defining 33 V overvoltage trip point for fault detection logic. Use Value: Delivers repeatable 31.35–34.65 V regulation window at 3.8 mA, ensuring tight OVP tolerance without trimming resistors. |
| Automotive Cabin Temperature Sensor | Programmable Logic Controller Analog Input |
Use Scenario: Biasing thermistor networks in HVAC control modules exposed to under-hood thermal cycling. IC Role / Device Role / Timing Role: Stable voltage reference for ratiometric measurement against microcontroller ADC reference. Use Value: Operates reliably from –65°C to +175°C with <0.1 µA leakage at 25 V, minimizing self-heating error in sealed enclosures. | Use Scenario: Providing isolated 33 V reference for 16-bit sigma-delta ADC front-ends in DIN-rail I/O modules. IC Role / Device Role / Timing Role: Low-noise shunt regulator supplying clean reference to precision instrumentation amplifiers. Use Value: 500 mW rating and 300 °C/W RJA allow direct PCB mounting without heatsinks in space-constrained industrial housings. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX55C33 (ON Semiconductor) | Same 33 V nominal, but 500 mW in DO-35 glass; higher ZZT (80 Ω), wider VZ tolerance (±5%) | Less stable regulation in precision analog circuits due to looser tolerance and higher impedance | Acceptable where cost sensitivity outweighs regulation accuracy requirements |
| MMSZ5257ET1G (onsemi) | SOD-123 package; identical VZ range and tempco, but lower Pd (350 mW) and higher RJA (450 °C/W) | Requires derating above 70°C ambient; unsuitable for high-temp industrial deployments | Preferred for space-constrained consumer boards where thermal margin is adequate |
Compared with BZX55C33 and MMSZ5257ET1G, ZMM5257B-7 offers superior thermal robustness (300 °C/W), tighter VZ tolerance (±5% vs ±5% but narrower min/max spread), and lower knee impedance - making it optimal for industrial-grade analog references demanding long-term stability.
Availability
ZMM5257B-7 is available at Aetrix Electronics and suitable for industrial sensor signal conditioning, USB-C power delivery feedback, automotive cabin temperature sensing, and programmable logic controller analog input requiring stable component supply across extended temperature ranges and multi-year production cycles.
Supply support for ZMM5257B-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.
ZMM52xxB series belongs to Diodes' precision Zener reference portfolio, engineered for high-stability voltage regulation in industrial, automotive, and communications infrastructure where hermetic reliability and tight parametric control are mandatory.
FAQ
What is the maximum continuous reverse current for reliable ZMM5257B-7 operation?
The ZMM5257B-7 is rated for 3.8 mA test current (IZT) and supports continuous reverse current up to 3.8 mA at 25°C ambient. At higher temperatures, derating applies per Figure 1: power dissipation drops linearly to zero at 150°C ambient, limiting usable current to ~2.5 mA at 100°C.
Can ZMM5257B-7 be used in forward-biased configurations?
Yes - its forward voltage is specified as 1.5 V at 200 mA, making it suitable for polarity-check circuits or low-current LED driver applications. However, it lacks forward surge ratings or switching speed characterization, so it should not be used in high-frequency or high-dI/dt switching roles.
How does the +0.092 %/°C temperature coefficient affect long-term reference stability?
This coefficient means the zener voltage increases by 0.092% per °C rise - approximately +30.4 mV/°C at 33 V. Over a –40°C to +125°C range, total drift is ~5.0 V, which must be compensated in system-level calibration. It is not drift-free but highly predictable and repeatable.
Is ZMM5257B-7 compliant with lead-free and RoHS requirements?
Yes - Diodes Incorporated confirms ZMM5257B-7 meets RoHS Directive 2011/65/EU and is manufactured with lead-free terminations compatible with standard SnPb and lead-free reflow profiles per J-STD-020. The MiniMELF glass body contains no restricted substances above threshold limits.
ZMM5257B-7 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Series:
- -
- Package/Case:
- DO-213AC, MINI-MELF, SOD-80
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Voltage - Zener (Nom) (Vz):
- 33 V
- Tolerance:
- ±5%
- Power - Max:
- 500 mW
- Impedance (Max) (Zzt):
- 58 Ohms
- Current - Reverse Leakage @ Vr:
- 100 nA @ 25 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.5 V @ 200 mA
- Operating Temperature:
- -65°C ~ 175°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- Mini MELF
ZMM5257B-7 FAQ
1.How can I place an order for ZMM5257B-7 through Aetrix?
Please submit a Request for Quotation (RFQ) for ZMM5257B-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 ZMM5257B-7 reliable?
The price and inventory of ZMM5257B-7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ZMM5257B-7 is usually 5 days.
3.What payment methods are accepted for ZMM5257B-7?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ZMM5257B-7 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ZMM5257B-7?
ZMM5257B-7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ZMM5257B-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 ZMM5257B-7?
For technical support, including ZMM5257B-7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ZMM5257B-7 requirements.
6.How does Aetrix verify that ZMM5257B-7 is sourced from the original manufacturer or authorized distributors?
All ZMM5257B-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 ZMM5257B-7 meets industry standards.
7.What is the process for return or replacement of ZMM5257B-7?
All ZMM5257B-7 units undergo pre-shipment inspection (PSI). If there is an issue with ZMM5257B-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 ZMM5257B-7 part is unused and in its original packaging.
Return procedure for ZMM5257B-7:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
ZMM5257B-7 Tags
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MMBZ5240B-7-F
Diodes Incorporated
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BZT52C5V6T-7
Diodes Incorporated
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MMSZ5231B-7-F
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BZT52C15-7-F
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BZX84C3V3LT1G
onsemi
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MMSZ5245BS-7-F
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MMSZ4682T1G
onsemi
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BZT52C15S-7-F
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MM5Z5V1ST1G
onsemi
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