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Diodes Incorporated 1N5249B-T
- Part No.:
- 1N5249B-T
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Zener Diodes
- Package:
- DO-204AH, DO-35, Axial
- Datasheet:
-
1N5249B-T.pdf
- Description:
- DIODE ZENER 19V 500MW DO35
- Quantity:
- Payment:
- Shipping:
Inventory:10,000
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Product details
Overview
1N5249B-T from Diodes Incorporated is a 19V, ±5% tolerance, 500mW surface-mount Zener diode in a hermetic DO-35 glass package, designed for precision voltage regulation and reference applications in power supply feedback loops, overvoltage protection circuits, and analog signal conditioning stages.
For engineers reviewing the 1N5249B-T datasheet, 1N5249B-T pinout, 1N5249B-T application, or 1N5249B-T equivalent, key selection criteria include Zener voltage (19V), test current (6.6mA), dynamic impedance (23Ω at IZT), temperature coefficient (+0.086%/°C), and RoHS-compliant Sn96.5Ag3.5 terminations.
Technical Context
This discrete Zener diode operates in reverse breakdown to maintain stable voltage across its terminals under varying load and temperature conditions. Its 23Ω Zener impedance at 6.6mA ensures low output variation, while the +0.086%/°C temperature coefficient enables predictable drift compensation in mid-range voltage references.
The DO-35 glass package provides hermetic sealing and thermal resistance of 300°C/W (junction-to-ambient), requiring lead temperature control ≤75°C at 9.5mm length for full 500mW dissipation. Polarity is marked by a cathode band, and the device is rated for -65°C to +175°C operation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 19V nominal, 18.05–19.95V range at 6.6mA - defines regulated output level with ±5% initial tolerance. |
| Power Dissipation (PD) | 500mW - maximum continuous DC power handling at TL ≤75°C with 9.5mm lead length. |
| Zener Impedance (ZZT) | 23Ω at IZT = 6.6mA - determines AC regulation stability and ripple rejection capability. |
| Temperature Coefficient | +0.086%/°C - quantifies VZ drift per degree Celsius above 25°C for thermal design margining. |
| Reverse Leakage (IR) | 0.1µA at VR = 14V - ensures minimal standby current in high-impedance bias networks. |
| Forward Voltage (VF) | 1.1V at IF = 200mA - relevant for polarity verification and ESD-safe handling during assembly. |
Pinout & Package
Package: DO-35 glass axial package with hermetic seal, cathode band marking, and Sn96.5Ag3.5 solderable terminations. Dimensions: A = 25.40mm (max), B = 4.00mm (max), C = 0.60mm (max), D = 2.00mm (max).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / Zener cathode reference ground | Connected to circuit ground or lower-potential node; reverse-biased relative to cathode for regulation. |
| Cathode | Zener breakdown terminal / regulated output node | Connected to input supply or error amplifier input; maintains stable 19V reference when reverse biased. |
Key Features
| Feature | Design Value |
|---|---|
| Hermetic glass package | Ensures long-term parameter stability and moisture resistance in harsh environments without conformal coating. |
| ±5% Zener voltage tolerance | Enables use in cost-sensitive applications where tight regulation is required but laser trimming is unnecessary. |
| Lead-free, RoHS-compliant finish | Sn96.5Ag3.5 terminations meet EU directives and support Pb-free reflow profiles (J-STD-020 Level 1). |
| Low Zener impedance (23Ω) | Minimizes output voltage deviation under dynamic load changes, improving transient response in feedback paths. |
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: Precision voltage reference for TL431-type shunt regulator or direct comparator input. Use Value: 19V Zener point sets accurate secondary-side regulation threshold with <23Ω impedance limiting loop gain variation. |
Use Scenario: Clamping transient surges on 15–24V industrial I/O lines to prevent downstream IC damage. IC Role / Device Role: Standalone overvoltage clamp activated above 19V, diverting excess energy to ground. Use Value: 500mW rating sustains short-duration transients; ±5% tolerance ensures reliable trip point within system safety margins. |
| Analog Sensor Signal Conditioning | Reference Voltage Generator |
Use Scenario: Providing stable bias voltage for op-amp-based bridge sensor amplifiers in automotive pressure sensors. IC Role / Device Role: Low-drift voltage reference for excitation or offset nulling in ratiometric measurement chains. Use Value: +0.086%/°C TC allows predictable calibration compensation across -40°C to +125°C operating range. |
Use Scenario: Generating fixed 19V reference for ADC input scaling or DAC output calibration in test equipment. IC Role / Device Role: Primary voltage reference source in unregulated linear supplies feeding precision analog subsystems. Use Value: Hermetic DO-35 package prevents parameter drift over time, ensuring long-term reference accuracy without recalibration. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener diode voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MMSZ5249B | Surface-mount SOD-123 package; same 19V/±5%/6.6mA spec; 350mW PD; 30Ω ZZT. | Lower power rating and higher impedance limit use in high-current or low-noise references. | Select for automated SMT assembly where board space is constrained and 350mW suffices. |
| 1N4742A | DO-41 package; 12V nominal; 1W PD; 9.5Ω ZZT; ±5% tolerance; different voltage grade. | Not a voltage match - requires redesign of reference network; suited for higher-power 12V systems. | Choose only if system requires 12V regulation and higher power handling; not a drop-in replacement. |
Compared with MMSZ5249B and 1N4742A, the 1N5249B-T offers superior thermal stability in hermetic glass packaging and higher power headroom than the SOD-123 variant, while providing exact 19V regulation unavailable in the 12V 1N4742A series.
Availability
1N5249B-T is available at Aetrix Electronics and suitable for switch-mode power supply feedback, overvoltage protection clamping, and analog sensor signal conditioning requiring stable component supply and long-term parametric consistency.
Supply support for 1N5249B-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, with design and manufacturing operations across Asia and the Americas.
The 1N52xxB series belongs to Diodes' legacy Zener diode product line, engineered for general-purpose voltage regulation and reference applications where reliability, hermeticity, and tight tolerance are prioritized over ultra-low impedance or high-frequency performance.
FAQ
Is the 1N5249B-T still in active production?
No - the 1N5249B-T is officially obsolete per Diodes Incorporated's DS18006 Rev. 19 (September 2019). It has been discontinued and replaced by the MMSZ5249B for new designs. Aetrix Electronics maintains limited legacy stock for repair and maintenance programs with full traceability and documentation.
What is the maximum allowable junction temperature for continuous operation?
The 1N5249B-T supports continuous operation from -65°C to +175°C junction temperature. However, full 500mW power dissipation is only valid when leads are maintained at ≤75°C with 9.5mm length; derating begins above that temperature per RθJA = 300°C/W.
Can this Zener diode be used in place of a 1N4742A?
No - the 1N5249B-T is a 19V Zener, while the 1N4742A is a 12V device. Their voltage ratings differ by 7V, making them non-interchangeable without circuit redesign. Substitution would cause incorrect regulation or failure to clamp at intended thresholds.
Does the DO-35 package support automated pick-and-place assembly?
The DO-35 axial package is not compatible with standard SMT pick-and-place equipment. It requires manual or wave-solder placement. For automated assembly, Diodes recommends the SOD-123-packaged MMSZ5249B as the designated replacement with identical electrical specs.
1N5249B-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):
- 19 V
- Tolerance:
- ±5%
- Power - Max:
- 500 mW
- Impedance (Max) (Zzt):
- 23 Ohms
- Current - Reverse Leakage @ Vr:
- 100 nA @ 14 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
1N5249B-T FAQ
1.How can I place an order for 1N5249B-T through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N5249B-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 1N5249B-T reliable?
The price and inventory of 1N5249B-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N5249B-T is usually 5 days.
3.What payment methods are accepted for 1N5249B-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N5249B-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N5249B-T?
1N5249B-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N5249B-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 1N5249B-T?
For technical support, including 1N5249B-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N5249B-T requirements.
6.How does Aetrix verify that 1N5249B-T is sourced from the original manufacturer or authorized distributors?
All 1N5249B-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 1N5249B-T meets industry standards.
7.What is the process for return or replacement of 1N5249B-T?
All 1N5249B-T units undergo pre-shipment inspection (PSI). If there is an issue with 1N5249B-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 1N5249B-T part is unused and in its original packaging.
Return procedure for 1N5249B-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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