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Diodes Incorporated 1N5242B-T
- Part No.:
- 1N5242B-T
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Zener Diodes
- Package:
- DO-204AH, DO-35, Axial
- Datasheet:
-
1N5242B-T.pdf
- Description:
- DIODE ZENER 12V 500MW DO35
- Quantity:
- Payment:
- Shipping:
Inventory:3,298
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Product details
Overview
1N5242B-T from Diodes Incorporated is a 12 V, ±5% tolerance, 500 mW surface-mount Zener diode in a hermetic DO-35 glass package, rated for operation from −65 °C to +175 °C, with 30 Ω zener impedance at 20 mA and 9.1 µA maximum reverse leakage at 9.1 V, used for precision voltage regulation in low-power analog reference circuits.
For engineers reviewing the 1N5242B-T datasheet, 1N5242B-T pinout, 1N5242B-T application, or 1N5242B-T equivalent, key selection criteria include its 12 V nominal zener voltage, ±5% tolerance, 300 °C/W thermal resistance, DO-35 mechanical form factor, and RoHS-compliant Sn96.5Ag3.5 terminations-critical for legacy board replacements and space-constrained voltage reference designs.
Technical Context
This discrete Zener diode operates in reverse breakdown to maintain stable voltage across its terminals under varying load and temperature conditions. Its 12 V nominal zener voltage is specified at 20 mA test current (IZT), with 30 Ω dynamic impedance (ZZT) and +0.077 %/°C temperature coefficient ensuring predictable drift behavior.
The device uses an epitaxial construction for high stability and low noise, housed in a hermetic glass DO-35 case with cathode band polarity marking. It supports lead-free reflow per J-STD-020 Level 1 moisture sensitivity and meets MIL-STD-202 solderability requirements.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 12 V nominal, 11.4–12.6 V range at 20 mA - defines regulated output voltage window |
| Power Dissipation (PD) | 500 mW - limits continuous steady-state power handling without heatsinking |
| Zener Impedance (ZZT) | 30 Ω at IZT = 20 mA - determines output voltage variation under load changes |
| Reverse Leakage (IR) | 1.0 µA max at VR = 9.1 V - ensures minimal quiescent current in standby regulation |
| Temp Coefficient (TC) | +0.077 %/°C - quantifies voltage drift per degree Celsius rise above 25 °C |
| Thermal Resistance (RθJA) | 300 °C/W - sets junction-to-ambient temperature rise per watt dissipated |
| Operating Temp Range | −65 °C to +175 °C - enables use in automotive under-hood and industrial environments |
Pinout & Package
Package: Hermetic DO-35 glass axial package with cathode band marking; dimensions: A ≤25.4 mm, B ≤4.0 mm, C ≤0.6 mm, D ≤2.0 mm; weight ≈0.13 g.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / Reverse bias reference ground | Connected to circuit ground or lower potential node during Zener operation |
| Cathode | Reverse breakdown terminal / Regulated output node | Provides stable 12 V reference when biased with current-limiting resistor |
Key Features
| Feature | Design Value |
|---|---|
| Hermetic glass package | Ensures long-term parameter stability and moisture immunity in harsh environments |
| ±5% zener voltage tolerance | Enables tight voltage reference accuracy without post-production trimming |
| Lead-free Sn96.5Ag3.5 finish | Supports Pb-free reflow assembly while maintaining MIL-STD-202 solderability |
| High-temperature operation | Rated up to +175 °C junction temperature for under-hood and industrial applications |
Applications
| Automotive Sensor Reference | Industrial Analog Input Module |
|---|---|
Use Scenario: Providing stable 12 V reference for pressure and temperature sensor signal conditioning circuits in engine control units. IC Role / Device Role / Timing Role: Zener voltage reference diode establishing precise bias point for op-amp input stages. Use Value: Maintains <±1% reference stability over −40 °C to +150 °C ambient, reducing calibration drift in production ECU units. | Use Scenario: Generating local 12 V rail for isolated ADC front-end amplifiers in programmable logic controller (PLC) analog input cards. IC Role / Device Role / Timing Role: Discrete shunt regulator supplying clean reference to instrumentation amplifiers and anti-aliasing filters. Use Value: Delivers 30 Ω dynamic impedance and <1 µA leakage at 9.1 V, minimizing gain error and offset drift in 16-bit measurement systems. |
| Legacy Power Supply Feedback | Low-Power IoT Node Voltage Clamp |
Use Scenario: Replacing obsolete Zeners in feedback networks of linear regulators powering legacy telecom line cards. IC Role / Device Role / Timing Role: Precision voltage clamp setting output voltage via optocoupler-coupled feedback loop. Use Value: Matches original 1N52xxB series mechanical and electrical specs, enabling drop-in replacement without PCB redesign. | Use Scenario: Protecting microcontroller GPIO pins and sensor interfaces against transient overvoltage in battery-powered environmental monitors. IC Role / Device Role / Timing Role: Bidirectional clamping element limiting input voltage to 12 V ±5% during ESD or surge events. Use Value: Leverages 500 mW power rating and 300 °C/W RθJA to absorb short-duration transients without thermal runaway. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MMSZ5242B | Surface-mount SOD-123 package; same 12 V, ±5%, 500 mW rating; 30 Ω ZZT; RoHS-compliant | Smaller footprint (2.7 × 1.6 mm vs DO-35's 4.0 mm diameter); higher density layout possible | Select for new designs requiring automated placement and space savings; not mechanically interchangeable |
| 1N4742A | 12 V, ±5%, 1 W power rating; DO-41 package; 22 Ω ZZT; higher thermal mass and derating margin | Higher power handling allows >20 mA continuous operation; larger axial package requires more board area | Select when sustained current >20 mA or improved thermal robustness is required; pin-compatible but longer leads |
Compared with MMSZ5242B and 1N4742A, the 1N5242B-T offers identical voltage specification and tolerance in a legacy-qualified DO-35 glass package ideal for repair, obsolescence mitigation, and high-reliability analog references where hermetic sealing matters.
Availability
1N5242B-T is available at Aetrix Electronics and suitable for automotive sensor reference, industrial analog input modules, and legacy power supply feedback circuits requiring stable component supply and long-lifecycle support.
Supply support for 1N5242B-T 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 high-reliability components.
The 1N52xxB series belongs to Diodes' legacy Zener diode product line, designed specifically for precision voltage reference and regulation in cost-sensitive, high-volume analog circuits where stability and manufacturability are critical.
FAQ
What is the maximum continuous reverse current the 1N5242B-T can handle at 12 V?
The 1N5242B-T is rated for 20 mA test current (IZT) and has a maximum power dissipation of 500 mW. At 12 V, this corresponds to a maximum continuous reverse current of approximately 41.7 mA (500 mW ÷ 12 V), provided thermal conditions remain within RθJA limits and leads are held at ≤75 °C.
Is the 1N5242B-T suitable for use in reflow soldering processes?
Yes-the 1N5242B-T features a lead-free Sn96.5Ag3.5 finish and complies with J-STD-020 Level 1 moisture sensitivity, making it compatible with standard Pb-free reflow profiles. Its glass DO-35 package withstands peak temperatures up to 260 °C for ≤60 seconds without degradation.
How does the +0.077 %/°C temperature coefficient affect regulation accuracy over temperature?
At +0.077 %/°C, the 1N5242B-T's zener voltage shifts by ~9.24 mV per 10 °C rise from 25 °C. Over a −40 °C to +125 °C range (ΔT = 150 °C), total drift is ~1.16 V-approximately ±4.8% of nominal 12 V. This must be factored into system-level reference tolerance budgets.
Why is the 1N5242B-T marked as obsolete, and what is the recommended replacement path?
Diodes Incorporated discontinued the 1N5242B-T as part of the broader 1N5221B–1N5267B family sunset, recommending MMSZ5242B for new designs. However, Aetrix Electronics maintains active inventory and traceable sourcing for ongoing production and repair of legacy systems requiring DO-35 form factor and hermetic reliability.
1N5242B-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Series:
- -
- Package/Case:
- DO-204AH, DO-35, Axial
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Voltage - Zener (Nom) (Vz):
- 12 V
- Tolerance:
- ±5%
- Power - Max:
- 500 mW
- Impedance (Max) (Zzt):
- 30 Ohms
- Current - Reverse Leakage @ Vr:
- 1 µA @ 9.1 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.1 V @ 200 mA
- Operating Temperature:
- -65°C ~ 200°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- DO-35
1N5242B-T FAQ
1.How can I place an order for 1N5242B-T through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N5242B-T 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 1N5242B-T reliable?
The price and inventory of 1N5242B-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N5242B-T is usually 5 days.
3.What payment methods are accepted for 1N5242B-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N5242B-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N5242B-T?
1N5242B-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N5242B-T 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 1N5242B-T?
For technical support, including 1N5242B-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N5242B-T requirements.
6.How does Aetrix verify that 1N5242B-T is sourced from the original manufacturer or authorized distributors?
All 1N5242B-T 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 1N5242B-T meets industry standards.
7.What is the process for return or replacement of 1N5242B-T?
All 1N5242B-T units undergo pre-shipment inspection (PSI). If there is an issue with 1N5242B-T, 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 1N5242B-T part is unused and in its original packaging.
Return procedure for 1N5242B-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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