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

Diodes Incorporated 1N5240B-T

Name: 1N5240B-T
Brand: Diodes Incorporated
SKU: 1N5240B-T
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 1N5240B-T

Manufacturer:: Diodes Incorporated

Category:: Single Zener Diodes

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

Datasheet:: 1N5240B-T.pdf

Description:: DIODE ZENER 10V 500MW DO35

Quantity:: RFQ Add To RFQ list

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Inventory:7,541

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Product details

Overview

1N5240B-T from Diodes Incorporated is a 10 V, ±5% tolerance, 500 mW surface-mount Zener diode in a hermetic DO-35 glass package, rated for 20 mA test current and 17 Ω dynamic impedance at I_ZT, used for precision voltage regulation and reference in low-power analog circuits.

For engineers reviewing the 1N5240B-T datasheet, 1N5240B-T pinout, 1N5240B-T application, or 1N5240B-T equivalent, key selection criteria include Zener voltage stability over temperature (+0.075 %/°C), low leakage (<3.0 µA at 8.0 V), RoHS-compliant Sn96.5Ag3.5 terminations, and DO-35 mechanical compatibility with legacy through-hole layouts.

Technical Context

This discrete Zener diode operates in reverse breakdown to maintain stable DC voltage under varying load and line conditions. Its 10 V nominal Zener voltage is specified at 20 mA with ±5% tolerance and exhibits a positive temperature coefficient of +0.075 %/°C, enabling predictable drift compensation in reference designs.

The device features a hermetic glass DO-35 package with cathode band polarity marking, 300 °C/W junction-to-ambient thermal resistance (at TL ≤75°C), and 1.1 V forward voltage at 200 mA - confirming suitability for bidirectional clamping and low-current biasing applications.

Key Specifications

Parameter	Value and Actual Design Meaning
Zener Voltage (V_Z)	10 V nominal, 9.5–10.5 V range at 20 mA - ensures tight regulation in 3.3 V/5 V system references.
Power Dissipation	500 mW - supports continuous operation in low-power regulators without heatsinking.
Zener Impedance (Z_ZT)	17 Ω at 20 mA - minimizes output voltage variation under load transients.
Reverse Leakage (I_R)	<3.0 µA at 8.0 V - enables high-impedance sensing and battery-backed reference stability.
Temp. Coefficient	+0.075 %/°C - allows predictable drift modeling for temperature-compensated references.
Forward Voltage	1.1 V at 200 mA - supports use as low-drop clamp or dual-purpose protection element.
Package	DO-35 glass - provides hermetic sealing and compatibility with wave-solder reflow profiles.

Pinout & Package

DO-35 glass axial package with cathode band marking; leads are Sn96.5Ag3.5 solderable per MIL-STD-202 Method 208; polarity identified by single black band on cathode end.

Pin/Terminal	Circuit Role	Design Meaning
Anode	Forward conduction terminal / Zener breakdown reference node	Connected to lower-potential side in shunt regulator; defines reference ground return path.
Cathode	Zener breakdown output / voltage clamp node	Connected to regulated rail; delivers stable 10 V when reverse-biased above knee voltage.

Key Features

Feature	Design Value
Hermetic Glass Package	DO-35 construction ensures long-term parameter stability and moisture immunity in industrial environments.
±5% Zener Tolerance	Tight initial voltage accuracy reduces need for post-production trimming in precision references.
Lead-Free & RoHS Compliant	Sn96.5Ag3.5 termination meets EU Directive 2015/863/EU without exemption reliance.
Low Thermal Resistance	300 °C/W junction-to-ambient enables reliable 500 mW operation with minimal board-level derating.

Applications

Power Supply Reference

Overvoltage Clamp

Use Scenario: Providing stable 10 V reference for ADC biasing and op-amp feedback networks in industrial sensor signal chains.

IC Role / Device Role / Timing Role: Shunt voltage reference establishing precise DC operating point for analog front-end circuitry.

Use Value: 17 Ω Z_ZT and +0.075 %/°C TC enable sub-10 mV drift over –40°C to +85°C ambient.

Use Scenario: Protecting microcontroller I/O pins from ESD-induced voltage spikes during hot-plug events in USB peripherals.

IC Role / Device Role / Timing Role: Bidirectional transient suppressor clamping both positive and negative excursions beyond safe logic thresholds.

Use Value: 1.1 V forward drop and 10 V reverse breakdown provide symmetrical ±10 V clamping window with fast response.

Current Source Bias

Temperature-Compensated Reference

Use Scenario: Generating constant current for LED biasing in optical encoder modules requiring stable luminance across supply variations.

IC Role / Device Role / Timing Role: Zener-based two-terminal current source where V_Z sets emitter-base voltage of series pass transistor.

Use Value: 500 mW rating supports up to 50 mA source current at 10 V with <1% regulation error.

Use Scenario: Paired with a negative-TC diode in series to create a near-zero-drift 10 V reference for calibration-grade multimeters.

IC Role / Device Role / Timing Role: Positive-temperature-coefficient element balancing negative-TC components in compensated reference topologies.

Use Value: +0.075 %/°C TC enables precise cancellation against common silicon diode TCs (≈−2 mV/°C).

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MMSZ5240B	Surface-mount SOD-123 package; same 10 V, ±5%, 500 mW rating; Z_ZT = 17 Ω at 20 mA.	Smaller footprint (2.7 × 1.6 mm vs. DO-35 length 4.0 mm); higher moisture sensitivity (Level 1 vs. Level 1, but smaller body).	Preferred for space-constrained PCBs; requires reflow profile adjustment due to smaller thermal mass.
1N4740A	Through-hole DO-41 package; 10 V, ±5%, 1 W power rating; Z_ZT = 20 Ω at 25 mA.	Higher power handling and lower thermal resistance (220 °C/W); larger board area and incompatible lead spacing.	Used where sustained >500 mW dissipation or legacy DO-41 layout compatibility is required.

Compared with MMSZ5240B and 1N4740A, the 1N5240B-T offers identical electrical specs in a hermetic DO-35 package - delivering superior long-term stability for mission-critical references where moisture ingress or parameter drift must be minimized, despite its obsolete status and tape-and-reel packaging limitation.

Availability

1N5240B-T is available at Aetrix Electronics and suitable for precision voltage reference, overvoltage protection, and current-source bias applications requiring stable component supply and traceable sourcing for legacy design support.

Supply support for 1N5240B-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, specializing in high-reliability components for industrial, computing, and consumer markets.

The 1N52xxB series was designed as a standardized family of hermetic Zener diodes for general-purpose voltage regulation and reference, targeting cost-sensitive yet stable analog subsystems in legacy equipment.

FAQ

Is the 1N5240B-T still in active production?

No - Diodes Incorporated has officially discontinued the 1N5240B-T and marked it as obsolete in DS18006 Rev. 19 (September 2019). Aetrix Electronics maintains limited legacy stock for design continuity and repair programs, with full traceability and RoHS documentation.

What is the maximum reverse voltage before breakdown for 1N5240B-T?

The 1N5240B-T begins transitioning into Zener breakdown near 9.5 V and reaches its specified 10 V nominal voltage at 20 mA test current. The absolute maximum non-destructive reverse voltage is not defined separately - operation above 10.5 V (max V_Z) risks exceeding power limits unless current is strictly limited.

Can 1N5240B-T replace 1N4740A in existing designs?

Electrically, yes - both deliver 10 V ±5% at comparable currents. Mechanically, no: 1N5240B-T uses DO-35 (glass, 4.0 mm max length) while 1N4740A uses DO-41 (plastic, 5.2 mm length, different lead spacing). Board redesign or adapter is required for physical substitution.

Why does the datasheet list "OBSOLETE – PART DISCONTINUED"?

This designation reflects Diodes Incorporated's formal end-of-life notice for the entire 1N5221B–1N5267B series. It indicates no new wafer fabrication, no future date codes, and no long-term manufacturing commitment - though functional equivalents like MMSZ5240B remain actively produced in SMD packages.

1N5240B-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):: 10 V

Tolerance:: ±5%

Power - Max:: 500 mW

Impedance (Max) (Zzt):: 17 Ohms

Current - Reverse Leakage @ Vr:: 3 µA @ 8 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

1N5240B-T FAQ

1.How can I place an order for 1N5240B-T through Aetrix?

Please submit a Request for Quotation (RFQ) for 1N5240B-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 1N5240B-T reliable?

The price and inventory of 1N5240B-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N5240B-T is usually 5 days.

3.What payment methods are accepted for 1N5240B-T?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N5240B-T transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 1N5240B-T?

1N5240B-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 1N5240B-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 1N5240B-T?

For technical support, including 1N5240B-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N5240B-T requirements.

6.How does Aetrix verify that 1N5240B-T is sourced from the original manufacturer or authorized distributors?

All 1N5240B-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 1N5240B-T meets industry standards.

7.What is the process for return or replacement of 1N5240B-T?

All 1N5240B-T units undergo pre-shipment inspection (PSI). If there is an issue with 1N5240B-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 1N5240B-T part is unused and in its original packaging.

Return procedure for 1N5240B-T:

1.Submit a request within 90 days.

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

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