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Microchip Technology 1N5257A
- Part No.:
- 1N5257A
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- DO-204AH, DO-35, Axial
- Datasheet:
-
1N5257A.pdf
- Description:
- DIODE ZENER 33V 500MW DO204AH
- Quantity:
- Payment:
- Shipping:
Inventory:3,630
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Product details
Overview
1N5257A from Microsemi is a 33 V, ±10% tolerance, 500 mW glass axial-lead Zener diode in DO-35 (DO-204AH) package, rated for 3.8 mA test current, 700 Ω dynamic impedance at knee current, and operating from –65°C to +175°C. It regulates voltage in low-power reference and protection circuits such as power supply feedback paths and overvoltage clamping.
For engineers reviewing the 1N5257A datasheet, 1N5257A pinout, 1N5257A application, or 1N5257A equivalent, key selection criteria include Zener voltage tolerance, thermal resistance (310°C/W on FR4), reverse leakage (<0.1 μA at 26.4 V), temperature coefficient (+0.092%/°C), and RoHS-compliant plating options.
Technical Context
This discrete Zener diode operates in reverse breakdown mode with cathode band indicating polarity. Its regulation stability relies on specified test current (IZT = 3.8 mA) and defined thermal path-junction-to-lead (250°C/W) or junction-to-ambient (310°C/W on FR4 with 4 mm² copper pads).
Electrical behavior is characterized by two impedance metrics: ZZT = 700 Ω at IZK = 0.25 mA (knee impedance), and ZZK = 700 Ω at IZK (per table footnote). Voltage drift is linearized via αVZ = +0.092%/°C, measured between 25°C and 125°C at rated IZT.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Nominal Zener Voltage | 33 V ±10% - defines regulated output level under 3.8 mA test current; actual regulation range: 29.7–36.3 V |
| Power Dissipation | 500 mW at 25°C - derates linearly to zero at 175°C ambient; requires thermal management above 50°C lead temp |
| Zener Impedance | 700 Ω at IZK = 0.25 mA - indicates knee sharpness and low-current regulation fidelity |
| Reverse Leakage | <0.1 μA at VR = 26.4 V - ensures minimal quiescent current in high-impedance bias networks |
| Temp. Coefficient | +0.092 %/°C - positive drift enables predictable voltage shift across industrial temperature range |
| Forward Voltage | ≤1.5 V at 200 mA - supports use as clamp or protection diode in forward conduction mode |
| Package | DO-35 (DO-204AH) - hermetically sealed glass axial-leaded case with tin-lead or matte-tin plating |
Pinout & Package
DO-35 (DO-204AH) glass axial-leaded package: hermetically sealed, 0.2 g weight, cathode indicated by single black band; leads are flexible axial terminals suitable for through-hole mounting.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Non-banded end | Connected to lower-potential node during Zener operation; carries full reverse current when regulating |
| Cathode | Banded end | Connected to higher-potential node; defines Zener breakdown polarity and voltage reference point |
Key Features
| Feature | Design Value |
|---|---|
| JEDEC-registered Zener | Complies with JEDEC 1N52xx standard for voltage regulation, enabling cross-manufacturer interchangeability |
| Radiation-hardened construction | Inherently radiation tolerant per MicroNote 050 - suitable for aerospace and high-reliability environments |
| ESD-insensitive | Passes MIL-STD-750 Method 1020 - eliminates need for ESD handling precautions during assembly |
| Low capacitance | Typical CJ < 5 pF (per Figure 2) - preserves signal integrity in RF and high-speed analog circuits |
| Wide temperature range | –65°C to +175°C operation - supports engine control, downhole, and military applications |
Applications
| Power Supply Feedback Reference | Overvoltage Clamp Protection |
|---|---|
Use Scenario: Stabilizing output voltage in linear regulator feedback loop using resistive divider. IC Role / Device Role / Timing Role: Precision voltage reference element setting regulation threshold. Use Value: ±10% tolerance and +0.092%/°C TC enable stable 33 V reference across –40°C to +85°C commercial range. | Use Scenario: Limiting transient voltage spikes on microcontroller I/O lines exposed to inductive loads. IC Role / Device Role / Timing Role: Shunt clamping device diverting excess energy to ground during overvoltage events. Use Value: 500 mW power rating and <0.1 μA leakage at 26.4 V ensure reliable clamping without loading normal operation. |
| Temperature-Stable Bias Network | Industrial Sensor Excitation Reference |
Use Scenario: Providing bias current to precision op-amp input stages in instrumentation amplifiers. IC Role / Device Role / Timing Role: Low-drift voltage source establishing stable DC operating point. Use Value: Positive TC compensates for negative TC of silicon transistors, improving overall circuit thermal stability. | Use Scenario: Supplying excitation voltage to RTD or strain gauge bridges in process control transmitters. IC Role / Device Role / Timing Role: Low-noise, low-capacitance reference source for bridge excitation. Use Value: <5 pF capacitance and 700 Ω knee impedance minimize AC coupling and maintain bridge balance accuracy. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4742A | 33 V ±5%, 1 W power rating, DO-41 package, 19 Ω ZZT, –65°C to +175°C | Higher power handling and tighter tolerance but larger footprint and different thermal resistance | Select when >500 mW dissipation or ±5% tolerance is required; verify PCB pad layout compatibility |
| BZX55-C33 | 33 V ±5%, 500 mW, DO-35 package, 80 Ω ZZT, –65°C to +150°C, RoHS-only | Lower dynamic impedance and same package, but reduced max temperature and no military screening options | Select for cost-sensitive commercial designs requiring tighter regulation and RoHS compliance only |
Compared with 1N5257A, 1N4742A offers higher power and tighter tolerance in a larger DO-41 package, while BZX55-C33 delivers lower impedance in identical DO-35 form but lacks extended temperature and screening options.
Availability
1N5257A is available at Aetrix Electronics and suitable for power supply feedback references, overvoltage clamp protection, and temperature-stable bias networks requiring stable component supply across industrial, aerospace, and test equipment programs.
Supply support for 1N5257A 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
Microsemi (now part of Microchip Technology) is a U.S.-based semiconductor company specializing in high-reliability, radiation-hardened, and high-voltage analog components.
The 1N52xx series was designed for precision voltage regulation in harsh-environment applications including aerospace, defense, and industrial control systems where wide temperature range and reliability are critical.
FAQ
What is the Zener voltage tolerance for the 1N5257A?
The 1N5257A has a nominal Zener voltage of 33 V with a ±10% tolerance, meaning its actual breakdown voltage falls between 29.7 V and 36.3 V when tested at 3.8 mA. This tolerance is confirmed in the Electrical Characteristics table and applies to all units marked with the "A" suffix. The 1N5257A is not rated for tighter tolerances like ±5% (B suffix) or ±1% (D suffix); those require different part numbers.
What is the maximum reverse leakage current for the 1N5257A?
The 1N5257A specifies a maximum reverse leakage current (IR) of 0.1 μA when tested at VR = 26.4 V (80% of nominal Zener voltage). This value is consistent across the A-suffix family and reflects tight control of minority carrier generation in the junction. Leakage remains stable over the full –65°C to +175°C operating range, supporting low-power standby modes.
Can the 1N5257A be used in surface-mount designs?
No - the 1N5257A is exclusively offered in the axial-leaded DO-35 (DO-204AH) glass package and is not a surface-mount device. For SMT equivalents, Microsemi offers the MLL5257A in DO-213AA (MELF) package. Substituting 1N5257A into an SMT layout would require mechanical adaptation and is not recommended due to thermal and reliability mismatch.
What is the thermal resistance of the 1N5257A when mounted on a PCB?
When mounted on an FR4 printed circuit board with 1 oz copper, 4 mm² copper pads, and 1 mm track width (25 mm length), the 1N5257A exhibits a junction-to-ambient thermal resistance of 310°C/W. This value determines safe power derating: at 25°C ambient, full 500 mW is allowed; at 75°C ambient, maximum dissipation drops to ~320 mW per the derating curve in Figure 1.
Does the 1N5257A support military-grade screening?
Yes - the base 1N5257A can be ordered with military screening prefixes (e.g., MV1N5257A for JANTXV) when combined with the "–1" internal bond option. These versions comply with MIL-PRF-19500 and include additional testing for vibration, shock, and temperature cycling. Standard 1N5257A parts do not include this screening unless explicitly ordered with MQ/MX/MV/MSP prefixes and "–1" suffix.
1N5257A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- DO-204AH, DO-35, Axial
- Packaging:
- Bulk
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 33 V
- Tolerance:
- ±10%
- 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 (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- DO-204AH (DO-35)
1N5257A FAQ
1.How can I place an order for 1N5257A through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N5257A 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 1N5257A reliable?
The price and inventory of 1N5257A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N5257A is usually 5 days.
3.What payment methods are accepted for 1N5257A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N5257A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N5257A?
1N5257A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N5257A 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 1N5257A?
For technical support, including 1N5257A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N5257A requirements.
6.How does Aetrix verify that 1N5257A is sourced from the original manufacturer or authorized distributors?
All 1N5257A 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 1N5257A meets industry standards.
7.What is the process for return or replacement of 1N5257A?
All 1N5257A units undergo pre-shipment inspection (PSI). If there is an issue with 1N5257A, 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 1N5257A part is unused and in its original packaging.
Return procedure for 1N5257A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1N5257A Tags
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MMBZ5240B-7-F
Diodes Incorporated
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