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Diodes Incorporated MMSZ5259B-7-F
- Part No.:
- MMSZ5259B-7-F
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Zener Diodes
- Package:
- SOD-123
- Datasheet:
-
MMSZ5259B-7-F.pdf
- Description:
- DIODE ZENER 39V 500MW SOD123
- Quantity:
- Payment:
- Shipping:
Inventory:32,182
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Product details
Overview
MMSZ5259B-7-F from Diodes Incorporated is a 39 V, 500 mW surface-mount Zener diode in SOD123 package, rated for 3.2 mA test current and 80 Ω dynamic impedance at 1 kHz, with 0.1 µA reverse leakage at 30 V, designed for precision voltage regulation and reference applications in power supply feedback loops and overvoltage protection circuits.
For engineers reviewing the MMSZ5259B-7-F datasheet, MMSZ5259B-7-F pinout, MMSZ5259B-7-F application, or MMSZ5259B-7-F equivalent, key selection criteria include nominal Zener voltage tolerance (±2.5%), thermal resistance (338 °C/W), AEC-Q101 qualification, lead-free RoHS compliance, and SOD123 footprint compatibility with automated PCB assembly.
Technical Context
This Zener diode operates in reverse breakdown mode to maintain stable voltage across its terminals under varying load and temperature conditions. Its 39 V nominal Zener voltage exhibits a positive temperature coefficient of +0.08 %/°C, and it delivers regulated output with 80 Ω impedance at 3.2 mA test current and 0.1 µA leakage at VR = 30 V.
The device is optimized for low-power, medium-current regulation in space-constrained designs. It features a cathode band polarity marker, matte tin-plated alloy 42 leads, and UL 94V-0 molded plastic case - all supporting high-reliability commercial and automotive applications per AEC-Q101.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (Nominal) | 39 V - precise regulation point for feedback networks and voltage references |
| Zener Voltage Range | 37.05–40.95 V - ±2.5% tolerance ensures predictable clamping in production |
| Test Current (IZT) | 3.2 mA - operating point where Zener voltage and impedance are specified |
| Zener Impedance (ZZT) | 80 Ω @ 1 kHz - low dynamic resistance enables stable regulation under small-signal variation |
| Power Dissipation | 370 mW @ TA = +25°C - defines maximum continuous power on standard FR-4 PCB |
| Reverse Leakage (IR) | 0.1 µA @ VR = 30 V - minimal off-state current preserves efficiency in standby modes |
| Thermal Resistance (RθJA) | 338 °C/W - quantifies junction-to-ambient heat transfer for thermal design margining |
Pinout & Package
Package: SOD123 - compact surface-mount outline with 1.55 mm body width, 2.65 mm length, and 1.05 mm height; cathode indicated by band marking; compatible with reflow soldering and automated pick-and-place.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / Zener cathode reference node | Connected to lower-potential side in reverse-biased regulation configuration |
| Cathode | Zener breakdown terminal / voltage reference output | Marked with band; connected to regulated output node in shunt regulator topologies |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive-grade reliability including temperature cycling, HTRB, and ESD testing |
| Lead-free & RoHS compliant | Fully compliant with EU Directive 2011/65/EU; no intentionally added lead or halogens |
| SOD123 package | Standardized footprint enabling drop-in replacement and high-density PCB layout |
| Low moisture sensitivity | MSL Level 1 per J-STD-020 - no baking required before assembly |
Applications
| Switch-Mode Power Supply Feedback | Overvoltage Protection Clamp |
|---|---|
Use Scenario: Regulating output voltage in isolated flyback converters via optocoupler-coupled feedback loop. IC Role / Device Role / Timing Role: Zener reference element setting error amplifier threshold in secondary-side control circuitry. Use Value: 39 V rating provides headroom above typical 24 V or 36 V rails while maintaining tight regulation with 80 Ω impedance. | Use Scenario: Clamping transient surges on 36 V industrial I/O lines during ESD or inductive switching events. IC Role / Device Role / Timing Role: Shunt protection device diverting excess energy to ground when line voltage exceeds 39 V. Use Value: 0.1 µA leakage at 30 V minimizes standby power loss; 370 mW dissipation handles short-duration transients without derating. |
| Reference Voltage Source | Automotive Sensor Biasing |
Use Scenario: Providing stable bias voltage for analog front-end op-amps in battery management systems. IC Role / Device Role / Timing Role: Precision DC reference node for ADC input scaling and offset calibration. Use Value: ±2.5% voltage tolerance and +0.08 %/°C TC ensure <1% drift over –40°C to +125°C operating range. | Use Scenario: Supplying regulated excitation voltage to resistive temperature sensors in engine control units. IC Role / Device Role / Timing Role: Stable 39 V source for ratiometric measurement circuits requiring known reference potential. Use Value: AEC-Q101 qualification guarantees operation under automotive thermal and vibration stress profiles. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX584-C39 | Same 39 V nominal, but 300 mW PD and SOD323 package (smaller footprint, higher RθJA) | Limited power handling; unsuitable for >200 mW sustained dissipation | Select only when board space is critical and thermal budget allows higher junction temperature |
| 1N4739A | 39 V, 1 W PD, DO-41 through-hole package; higher leakage (1 µA @ 30 V) | Requires manual or wave soldering; incompatible with SMT-only lines | Choose for prototyping or legacy through-hole designs where thermal margin is primary concern |
Compared with BZX584-C39 and 1N4739A, MMSZ5259B-7-F uniquely balances SMT compatibility, AEC-Q101 qualification, and 370 mW on-board dissipation - making it optimal for automotive and industrial surface-mount power regulation where reliability and assembly automation are mandatory.
Availability
MMSZ5259B-7-F is available at Aetrix Electronics and suitable for switch-mode power supplies, overvoltage protection circuits, precision voltage references, and automotive sensor biasing requiring stable component supply and full traceability.
Supply support for MMSZ5259B-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, with design, manufacturing, and sales operations across Asia, Europe, and North America.
The MMSZ series belongs to Diodes' general-purpose Zener diode product line, engineered specifically for cost-sensitive, high-volume applications demanding consistent voltage regulation, AEC-Q101 reliability, and full RoHS/Green compliance in compact SMD packages.
FAQ
What is the maximum power dissipation of MMSZ5259B-7-F at 75°C ambient?
The device supports 500 mW power dissipation at TL = +75°C (lead temperature), per datasheet Note 4. At TA = +25°C, the rated power is 370 mW on FR-4 with 1-inch copper pad. Derating follows the curve in Figure 1: linear reduction to zero at +150°C junction temperature.
Does MMSZ5259B-7-F have a defined temperature coefficient?
Yes - Figure 6 shows a typical temperature coefficient of +0.08 %/°C for the MMSZ5259B (39 V) variant. This positive TC means Zener voltage increases slightly with rising temperature, enabling compensation in multi-diode reference designs.
Is the SOD123 package of MMSZ5259B-7-F compatible with standard reflow profiles?
Yes - the device is qualified for Pb-free reflow per JEDEC J-STD-020, with MSL Level 1 rating. No pre-baking is required. Recommended peak temperature is ≤260°C, with time above 217°C limited to 60–150 seconds per IPC/JEDEC standards.
How is polarity identified on the MMSZ5259B-7-F package?
Polarity is marked by a cathode band - a visible dark stripe near one end of the SOD123 body. The terminal adjacent to the band is the cathode; the opposite end is the anode. This matches industry-standard SOD123 orientation used in CAD footprints and assembly drawings.
MMSZ5259B-7-F Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Series:
- -
- Package/Case:
- SOD-123
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 39 V
- Tolerance:
- ±5%
- Power - Max:
- 500 mW
- Impedance (Max) (Zzt):
- 80 Ohms
- Current - Reverse Leakage @ Vr:
- 100 nA @ 30 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
MMSZ5259B-7-F FAQ
1.How can I place an order for MMSZ5259B-7-F through Aetrix?
Please submit a Request for Quotation (RFQ) for MMSZ5259B-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 MMSZ5259B-7-F reliable?
The price and inventory of MMSZ5259B-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 MMSZ5259B-7-F is usually 5 days.
3.What payment methods are accepted for MMSZ5259B-7-F?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMSZ5259B-7-F transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MMSZ5259B-7-F?
MMSZ5259B-7-F orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MMSZ5259B-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 MMSZ5259B-7-F?
For technical support, including MMSZ5259B-7-F datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMSZ5259B-7-F requirements.
6.How does Aetrix verify that MMSZ5259B-7-F is sourced from the original manufacturer or authorized distributors?
All MMSZ5259B-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 MMSZ5259B-7-F meets industry standards.
7.What is the process for return or replacement of MMSZ5259B-7-F?
All MMSZ5259B-7-F units undergo pre-shipment inspection (PSI). If there is an issue with MMSZ5259B-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 MMSZ5259B-7-F part is unused and in its original packaging.
Return procedure for MMSZ5259B-7-F:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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