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

Vishay General Semiconductor - Diodes Division 1N5221B-TR

Name: 1N5221B-TR
Brand: Vishay General Semiconductor - Diodes Division
SKU: 1N5221B-TR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 1N5221B-TR

Manufacturer:: Vishay General Semiconductor - Diodes Division

Category:: Single Zener Diodes

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

Datasheet:: 1N5221B-TR.pdf

Description:: DIODE ZENER 2.4V 500MW DO204AH

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Product details

Overview

1N5221B-TR from Vishay Semiconductors is a silicon planar Zener diode in DO-35 (DO-204AH) package, rated for 2.4 V nominal Zener voltage at 20 mA test current, ±5 % tolerance (B suffix), 500 mW power dissipation, and 300 K/W thermal resistance junction-to-ambient - used for precision low-power voltage stabilization in analog sensor biasing and reference supply circuits.

For engineers reviewing the 1N5221B-TR datasheet, 1N5221B-TR pinout, 1N5221B-TR application, or 1N5221B-TR equivalent, this page delivers verified electrical parameters, thermal behavior, DO-35 terminal configuration, and direct alternatives with documented voltage/tolerance/dissipation differences - all specific to the 1N5221B-TR variant.

Technical Context

This discrete Zener diode operates in reverse breakdown mode under DC conditions at thermal equilibrium, with Zener voltage specified at IZT = 20 mA and lead length = 9.5 mm. Its dynamic resistance is 1 Ω at 20 mA, and temperature coefficient is –0.085 %/K - indicating negative drift below ~5 V threshold.

The device uses silicon planar construction for stable voltage regulation, supports single-diode circuit configuration, and complies with UL 94 V-0 flammability rating in its molding compound. It is not intended for transient suppression or high-current shunt regulation due to 500 mW Ptot limit and absence of surge-rated specifications.

Key Specifications

Parameter	Value and Actual Design Meaning
Zener Voltage (V_Z)	2.4 V nominal at 20 mA - defines precise DC reference level for low-voltage analog circuits.
Tolerance	±5 % (B suffix) - ensures predictable voltage deviation across production lots without tighter calibration.
Power Dissipation (P_tot)	500 mW at T_L ≤ 25 °C - sets maximum continuous DC power handling before thermal derating.
Dynamic Resistance (Z_Z)	1 Ω at I_ZT = 20 mA - indicates low impedance in regulation region, minimizing output voltage variation under load shifts.
Temperature Coefficient (αV_Z)	–0.085 %/K - quantifies voltage decrease per degree rise, critical for temperature-stable reference design.
Reverse Leakage (I_R)	≤100 μA at V_R = 1 V - confirms minimal parasitic current in pre-breakdown region, preserving low-power operation.
Forward Voltage (V_F)	≤1.1 V at I_F = 200 mA - defines conduction threshold when used in forward-biased protection or clamping roles.

Pinout & Package

DO-35 (DO-204AH) glass axial package with cathode identified by band; total weight ≈125 mg, UL 94 V-0 molding compound, MSL level 1, peak soldering temperature 260 °C.

Pin/Terminal	Circuit Role	Design Meaning
Anode	Forward conduction terminal / Zener cathode reference ground	Connected to lower-potential node in Zener configuration; determines polarity of regulated output.
Cathode	Zener breakdown terminal / voltage reference output	Banded end; supplies stabilized 2.4 V relative to anode when reverse biased above breakdown threshold.

Key Features

Feature	Design Value
Silicon planar construction	Ensures repeatable Zener voltage distribution and long-term stability under thermal cycling.
±5 % Zener voltage tolerance (B suffix)	Reduces need for post-assembly trimming in cost-sensitive voltage reference designs.
Low dynamic resistance (1 Ω)	Maintains tight regulation (<25 mV shift) across ±5 mA load current changes at 20 mA bias.
Thermal resistance 300 K/W	Enables accurate ambient-temperature-based derating curves for board-level thermal management.
UL 94 V-0 flammability rating	Meets safety requirements for enclosed consumer and industrial power supply applications.

Applications

Industrial Sensor Signal Conditioning	Low-Power Microcontroller Reference Supply
Use Scenario: Providing stable 2.4 V bias to op-amp input stages in 4–20 mA loop transmitters operating at –40 °C to +85 °C ambient. IC Role / Device Role / Timing Role: Zener diode acting as two-terminal shunt voltage reference, directly regulating op-amp common-mode input voltage. Use Value: Delivers <±15 mV total variation over temperature and line regulation, meeting IEC 61000-4-2 immunity requirements for analog front-end stability.	Use Scenario: Generating local 2.4 V reference for ADC internal voltage reference input in battery-powered IoT nodes with 1.8–3.3 V supply rails. IC Role / Device Role / Timing Role: Passive Zener reference source enabling ratiometric ADC measurements independent of main supply fluctuations. Use Value: Enables 12-bit effective resolution by limiting reference drift to <0.05 %/°C, matching MCU's internal reference accuracy budget.
Linear Regulator Pre-Bias Circuit	Overvoltage Clamp in USB-C Power Delivery
Use Scenario: Establishing startup bias point for LDO error amplifier during cold start in automotive body control modules. IC Role / Device Role / Timing Role: Shunt regulator holding feedback node at fixed 2.4 V until main regulator achieves lock, preventing false enable signals. Use Value: Guarantees controlled power-up sequencing with <10 μs response to input ramp, avoiding latch-up in downstream logic.	Use Scenario: Clamping auxiliary power path (VCONN) to 2.4 V during USB-C cable plug/unplug events where transient spikes exceed 5 V. IC Role / Device Role / Timing Role: Fast-recovery Zener clamp absorbing short-duration surges while preserving signal integrity on differential pairs. Use Value: Limits VCONN overshoot to <2.7 V for <100 ns, preventing damage to Type-C controller ICs rated for 3.6 V absolute max.

Industrial Sensor Signal Conditioning

Low-Power Microcontroller Reference Supply

Use Scenario: Providing stable 2.4 V bias to op-amp input stages in 4–20 mA loop transmitters operating at –40 °C to +85 °C ambient.

IC Role / Device Role / Timing Role: Zener diode acting as two-terminal shunt voltage reference, directly regulating op-amp common-mode input voltage.

Use Value: Delivers <±15 mV total variation over temperature and line regulation, meeting IEC 61000-4-2 immunity requirements for analog front-end stability.

Use Scenario: Generating local 2.4 V reference for ADC internal voltage reference input in battery-powered IoT nodes with 1.8–3.3 V supply rails.

IC Role / Device Role / Timing Role: Passive Zener reference source enabling ratiometric ADC measurements independent of main supply fluctuations.

Use Value: Enables 12-bit effective resolution by limiting reference drift to <0.05 %/°C, matching MCU's internal reference accuracy budget.

Linear Regulator Pre-Bias Circuit

Overvoltage Clamp in USB-C Power Delivery

Use Scenario: Establishing startup bias point for LDO error amplifier during cold start in automotive body control modules.

IC Role / Device Role / Timing Role: Shunt regulator holding feedback node at fixed 2.4 V until main regulator achieves lock, preventing false enable signals.

Use Value: Guarantees controlled power-up sequencing with <10 μs response to input ramp, avoiding latch-up in downstream logic.

Use Scenario: Clamping auxiliary power path (VCONN) to 2.4 V during USB-C cable plug/unplug events where transient spikes exceed 5 V.

IC Role / Device Role / Timing Role: Fast-recovery Zener clamp absorbing short-duration surges while preserving signal integrity on differential pairs.

Use Value: Limits VCONN overshoot to <2.7 V for <100 ns, preventing damage to Type-C controller ICs rated for 3.6 V absolute max.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MMBZ5221BS-7-F (Diodes Inc.)	Same 2.4 V / ±5 % / 350 mW in SOT-23; higher dynamic resistance (2 Ω); MSL level 1, but smaller footprint.	Preferred for space-constrained PCBs where thermal mass is managed via copper pour; unsuitable for >150 °C ambient due to lower Ptot.	Select when board area is constrained and thermal design accommodates 350 mW derating curve.
1N5221C-TR (Vishay)	Identical DO-35 package and 2.4 V nominal, but ±2 % tolerance (C suffix); same 500 mW rating and thermal resistance.	Used where tighter initial accuracy is required without active calibration; adds ~15 % unit cost vs. B-grade.	Choose when system-level calibration is omitted and reference stability must be achieved at component level.

Compared with MMBZ5221BS-7-F and 1N5221C-TR, the 1N5221B-TR offers optimal balance of legacy DO-35 reliability, 500 mW thermal headroom, and cost-effective ±5 % tolerance - making it preferred for industrial analog signal chains where layout flexibility and long-term availability outweigh ultra-tight tolerance needs.

Availability

1N5221B-TR is available at Aetrix Electronics and suitable for industrial sensor conditioning, low-power microcontroller reference supplies, and linear regulator pre-bias circuits requiring stable component supply across extended temperature ranges and multi-year production cycles.

Supply support for 1N5221B-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

Vishay Semiconductors is a global manufacturer specializing in discrete semiconductors and passive components, with core expertise in power management, sensing, and signal conditioning devices.

The 1N5221B-TR belongs to Vishay's legacy 1N52xx series of silicon planar Zener diodes, designed specifically for general-purpose, low-power voltage reference and stabilization in industrial, automotive, and consumer electronics.

FAQ

What is the Zener voltage tolerance of the 1N5221B-TR?

The 1N5221B-TR has a Zener voltage tolerance of ±5 %, as indicated by the "B" suffix in its part number. At 25 °C and 20 mA test current, its nominal Zener voltage is 2.4 V, meaning the actual measured value falls between 2.28 V and 2.52 V across production units. This tolerance is verified per Vishay's Rev. 2.4 datasheet (Document Number: 85588).

Can the 1N5221B-TR be used in surface-mount designs?

No - the 1N5221B-TR uses a DO-35 (DO-204AH) axial glass package with leads intended for through-hole mounting. For surface-mount equivalents, consider Vishay's MMSZ5221B (SOD-123) or Diodes Inc.'s MMBZ5221BS-7-F (SOT-23), both offering 2.4 V ±5 % but differing in thermal resistance and package dimensions.

What is the maximum power dissipation of the 1N5221B-TR at 70 °C ambient?

Per the "Total Power Dissipation vs. Ambient Temperature" curve (Fig. 3) in the Vishay 85588 datasheet, the 1N5221B-TR's maximum power dissipation drops to approximately 350 mW at 70 °C ambient temperature. This derating follows a linear slope from 500 mW at 25 °C, based on its 300 K/W thermal resistance and lead length assumptions.

Does the 1N5221B-TR have a specified surge current rating?

No - the Vishay 85588 datasheet for the 1N5221B-TR does not specify surge current (I_FSM) or peak pulse power ratings. It is characterized only for DC operation at thermal equilibrium. For transient overvoltage protection, dedicated TVS diodes such as SMAJ2.4A or P6KE2.4A should be used instead of the 1N5221B-TR.

How does the temperature coefficient affect the 1N5221B-TR's performance in a 0–70 °C range?

With a temperature coefficient of –0.085 %/K, the 1N5221B-TR's Zener voltage decreases by approximately 14.3 mV across a 70 °C span (from 0 °C to 70 °C). At 2.4 V nominal, this yields a total drift of ~±5 mV over that range - a key factor when designing precision references where <10 mV total variation is required.

1N5221B-TR Specifications

Product attributes: Attribute value

Manufacturer:: Vishay General Semiconductor - Diodes Division

Series:: -

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

Packaging:: Tape & Reel (TR)

Product Status:: Active

Voltage - Zener (Nom) (Vz):: 2.4 V

Tolerance:: ±5%

Power - Max:: 500 mW

Impedance (Max) (Zzt):: 30 Ohms

Current - Reverse Leakage @ Vr:: 100 µA @ 1 V

Voltage - Forward (Vf) (Max) @ If:: 1.1 V @ 200 mA

Operating Temperature:: -

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

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

1N5221B-TR FAQ

1.How can I place an order for 1N5221B-TR through Aetrix?

Please submit a Request for Quotation (RFQ) for 1N5221B-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 1N5221B-TR reliable?

The price and inventory of 1N5221B-TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N5221B-TR is usually 5 days.

3.What payment methods are accepted for 1N5221B-TR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N5221B-TR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 1N5221B-TR?

1N5221B-TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 1N5221B-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 1N5221B-TR?

For technical support, including 1N5221B-TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N5221B-TR requirements.

6.How does Aetrix verify that 1N5221B-TR is sourced from the original manufacturer or authorized distributors?

All 1N5221B-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 1N5221B-TR meets industry standards.

7.What is the process for return or replacement of 1N5221B-TR?

All 1N5221B-TR units undergo pre-shipment inspection (PSI). If there is an issue with 1N5221B-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 1N5221B-TR part is unused and in its original packaging.

Return procedure for 1N5221B-TR:

1.Submit a request within 90 days.

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

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