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Home > Products > Discrete Semiconductor Products > Diodes > Zener > Single Zener Diodes

Microchip Technology 1N5257B/TR

Name: 1N5257B/TR
Brand: Microchip Technology
SKU: 1N5257B/TR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 1N5257B/TR

Manufacturer:: Microchip Technology

Category:: Single Zener Diodes

Package:: DO-204AH, DO-35, Axial

Datasheet:: 1N5257B/TR.pdf

Description:: DIODE ZENER 33V 500MW DO204AH

Quantity:: RFQ Add To RFQ list

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Inventory:9,920

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Product details

Overview

1N5257B/TR from Microsemi is a 500 mW, 33 V ±5% glass axial-lead Zener diode in DO-35 (DO-204AH) package, with 3.8 Ω dynamic impedance at 20 mA test current, -65°C to +175°C operating temperature range, and cathode band polarity marking-used for precision voltage reference and overvoltage protection in low-power analog circuits.

For engineers reviewing the 1N5257B/TR datasheet, 1N5257B/TR pinout, 1N5257B/TR application, or 1N5257B/TR 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 tin plating with TR tape-and-reel packaging.

Technical Context

This discrete Zener diode operates in reverse breakdown to maintain stable voltage regulation across wide current (0.25–20 mA) and temperature (-65°C to +175°C) ranges. Its DO-35 glass package provides hermetic sealing and inherent radiation hardness per MicroNote 050.

It exhibits minimal junction capacitance (typ. <2 pF at 0 V, per Figure 2), low forward voltage (≤1.5 V @ 200 mA), and JEDEC-registered compliance with guaranteed limits on V_Z, I_R, and V_F-with full six-parameter specification enabled by the "B" suffix (±5% tolerance).

Key Specifications

Parameter	Value and Actual Design Meaning
Nominal Zener Voltage	33 V ±5% at 20 mA test current-defines regulated output voltage under standard bias conditions.
Power Dissipation	500 mW at 25°C, derated linearly to zero at 175°C-sets maximum continuous power handling on PCB or lead mount.
Zener Impedance	3.8 Ω at I_ZT = 20 mA-determines regulation stiffness and AC ripple rejection capability.
Reverse Leakage Current	<0.1 μA at 26.4 V (80% of V_Z)-ensures low standby power loss in high-impedance bias networks.
Temperature Coefficient	+0.092 %/°C-quantifies V_Z drift with ambient temperature change, critical for stable references.
Operating Temperature	-65°C to +175°C-supports deployment in aerospace, downhole, and industrial environments.
Package	DO-35 (DO-204AH) glass axial-leaded-enables through-hole mounting with flexible lead forming and hermetic reliability.

Pinout & Package

DO-35 (DO-204AH) hermetically sealed glass axial-leaded package with tin-lead or RoHS-compliant matte-tin plating; cathode indicated by colored band; weight 0.2 g.

Pin/Terminal	Circuit Role	Design Meaning
Anode	Non-banded end	Connected to circuit ground or lower potential node during Zener operation.
Cathode	Banded end	Connected to regulated voltage node; must be held positive relative to anode for breakdown conduction.

Key Features

Feature	Design Value
JEDEC-registered Zener	Guaranteed V_Z, I_R, and V_F limits-ensures interchangeability and qualification traceability.
±5% voltage tolerance (B suffix)	Enables tighter regulation than ±10% (A) or ±20% (non-suffix) variants-reduces calibration overhead.
RoHS-compliant option (e3)	Meets environmental compliance without performance trade-off-supports global manufacturing requirements.
Tape-and-reel packaging (TR)	Enables automated SMT placement compatibility despite axial-leaded form-improves assembly efficiency.
Radiation-hardened design	Inherent hardness per MicroNote 050-validates use in space-grade and nuclear instrumentation systems.

Applications

Reference Voltage Generator	Overvoltage Clamp
Use Scenario: Providing stable 33 V reference for ADC biasing and op-amp feedback networks in sensor signal conditioning modules. IC Role / Device Role / Timing Role: Voltage reference element establishing precise DC operating point independent of supply variation. Use Value: 3.8 Ω Zener impedance and +0.092%/°C tempco enable ≤0.5% total error over -40°C to +85°C industrial range.	Use Scenario: Protecting microcontroller I/O pins from transient surges exceeding 33 V in industrial PLC input stages. IC Role / Device Role / Timing Role: Shunt clamping device diverting excess energy to ground before damage threshold is reached. Use Value: Sub-μA leakage at 26.4 V ensures negligible loading on protected circuit; 500 mW rating handles short-duration transients.
Low-Power Regulator	Temperature-Stable Bias Network
Use Scenario: Generating local 33 V rail for analog front-end ICs where LDO dropout or efficiency is impractical. IC Role / Device Role / Timing Role: Simple shunt regulator maintaining constant voltage across load via series resistor. Use Value: 500 mW dissipation supports up to 15 mA load current at 33 V with adequate heatsinking via leads.	Use Scenario: Setting bias points in RF amplifier stages requiring minimal V_BE drift over temperature. IC Role / Device Role / Timing Role: Precision voltage source compensating transistor parameter shifts with ambient temperature. Use Value: +0.092%/°C tempco enables predictable compensation slope-matching typical silicon V_BE drift direction.

Reference Voltage Generator

Overvoltage Clamp

Use Scenario: Providing stable 33 V reference for ADC biasing and op-amp feedback networks in sensor signal conditioning modules.

IC Role / Device Role / Timing Role: Voltage reference element establishing precise DC operating point independent of supply variation.

Use Value: 3.8 Ω Zener impedance and +0.092%/°C tempco enable ≤0.5% total error over -40°C to +85°C industrial range.

Use Scenario: Protecting microcontroller I/O pins from transient surges exceeding 33 V in industrial PLC input stages.

IC Role / Device Role / Timing Role: Shunt clamping device diverting excess energy to ground before damage threshold is reached.

Use Value: Sub-μA leakage at 26.4 V ensures negligible loading on protected circuit; 500 mW rating handles short-duration transients.

Low-Power Regulator

Temperature-Stable Bias Network

Use Scenario: Generating local 33 V rail for analog front-end ICs where LDO dropout or efficiency is impractical.

IC Role / Device Role / Timing Role: Simple shunt regulator maintaining constant voltage across load via series resistor.

Use Value: 500 mW dissipation supports up to 15 mA load current at 33 V with adequate heatsinking via leads.

Use Scenario: Setting bias points in RF amplifier stages requiring minimal V_BE drift over temperature.

IC Role / Device Role / Timing Role: Precision voltage source compensating transistor parameter shifts with ambient temperature.

Use Value: +0.092%/°C tempco enables predictable compensation slope-matching typical silicon V_BE drift direction.

Equivalent & Alternatives

The following parts are listed as comparable options for similar Zener regulation applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
1N4733A	33 V ±5%, 1 W power rating, DO-41 package, higher thermal resistance (500°C/W junction-to-ambient)	Suitable for higher-power regulation but requires larger PCB footprint and different lead spacing	Select when >500 mW dissipation or legacy DO-41 layout compatibility is required
MMBZ5257BS	33 V ±5%, SOT-23 surface-mount package, 200 mW rating, 30 Ω Z_ZT	Designed for space-constrained PCBs; not interchangeable due to package and power differences	Select for automated high-density assembly where axial-leaded form is unacceptable

Compared with 1N4733A and MMBZ5257BS, the 1N5257B/TR offers optimal balance of precision (±5%), compact DO-35 form factor, and proven high-temperature reliability-making it preferred for aerospace, downhole, and military screening applications where hermeticity and radiation hardness are mandatory.

Availability

1N5257B/TR is available at Aetrix Electronics and suitable for precision voltage reference, overvoltage protection, and low-power regulation applications requiring stable component supply across aerospace, industrial control, and test equipment programs.

Supply support for 1N5257B/TR 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-temperature analog and mixed-signal components.

The 1N52xxB series belongs to Microsemi's legacy Zener diode product line engineered for mission-critical voltage regulation in extreme environments-including space, defense, and oilfield electronics.

FAQ

What is the Zener voltage tolerance of the 1N5257B/TR?

The 1N5257B/TR has a nominal Zener voltage of 33 V with a guaranteed tolerance of ±5%, as indicated by the "B" suffix per JEDEC specification. This tolerance is fully characterized and tested at 20 mA Zener test current and 25°C ambient temperature, ensuring consistent regulation accuracy across production lots.

Does the 1N5257B/TR support RoHS compliance?

Yes-the 1N5257B/TR is available in RoHS-compliant form with annealed matte-tin plating, designated by the "e3" suffix (e.g., 1N5257B-e3/TR). The base part number without "e3" uses traditional tin-lead plating, but both versions share identical electrical specifications and DO-35 mechanical form.

What is the maximum reverse leakage current for the 1N5257B/TR?

The 1N5257B/TR specifies a maximum reverse leakage current of 0.1 μA at 26.4 V (80% of nominal 33 V Zener voltage), measured at 25°C. This ultra-low leakage ensures minimal power loss in high-impedance reference networks and preserves accuracy in battery-powered or low-quiescent-current designs.

Can the 1N5257B/TR be used in high-temperature environments?

Yes-the 1N5257B/TR is rated for continuous operation from -65°C to +175°C and features hermetic glass packaging that maintains parameter stability across this full range. Its thermal resistance is 310°C/W junction-to-ambient on FR4 board, enabling reliable function in downhole tools, engine control units, and avionics enclosures.

What does the "TR" suffix indicate in 1N5257B/TR?

The "TR" suffix in 1N5257B/TR denotes tape-and-reel packaging per EIA-296 standard, enabling automated pick-and-place assembly despite its axial-leaded DO-35 form. This configuration supports high-volume manufacturing while preserving the device's electrical and thermal characteristics-no derating or requalification is needed.

1N5257B/TR Specifications

Product attributes: Attribute value

Manufacturer:: Microchip Technology

Series:: -

Package/Case:: DO-204AH, DO-35, Axial

Packaging:: Tape & Reel (TR)

Product Status:: Active

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 (TA)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: DO-204AH (DO-35)

1N5257B/TR FAQ

1.How can I place an order for 1N5257B/TR through Aetrix?

Please submit a Request for Quotation (RFQ) for 1N5257B/TR 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 1N5257B/TR reliable?

The price and inventory of 1N5257B/TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N5257B/TR is usually 5 days.

3.What payment methods are accepted for 1N5257B/TR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N5257B/TR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 1N5257B/TR?

1N5257B/TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 1N5257B/TR 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 1N5257B/TR?

For technical support, including 1N5257B/TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N5257B/TR requirements.

6.How does Aetrix verify that 1N5257B/TR is sourced from the original manufacturer or authorized distributors?

All 1N5257B/TR 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 1N5257B/TR meets industry standards.

7.What is the process for return or replacement of 1N5257B/TR?

All 1N5257B/TR units undergo pre-shipment inspection (PSI). If there is an issue with 1N5257B/TR, 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 1N5257B/TR part is unused and in its original packaging.

Return procedure for 1N5257B/TR:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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