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

onsemi 1N4372A_T50R

Name: 1N4372A_T50R
Brand: onsemi
SKU: 1N4372A_T50R
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 1N4372A_T50R

Manufacturer:: onsemi

Category:: Single Zener Diodes

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

Datasheet:: 1N4372A_T50R.pdf

Description:: DIODE ZENER 3V 500MW DO35

Quantity:: RFQ Add To RFQ list

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Inventory:4,146

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Product details

Overview

1N4372A_T50R from Fairchild Semiconductor is a 3.0 V ±5% Zener diode in DO-35 glass package, rated for 500 mW power dissipation at TL ≤ 75°C, with 29 Ω dynamic impedance at 20 mA and 120 mA maximum Zener current. It provides precision voltage regulation in low-power analog reference and overvoltage protection circuits.

For engineers reviewing the 1N4372A_T50R datasheet, pinout, applications, or equivalent options, key selection criteria include zener voltage tolerance, thermal derating behavior, cathode band identification, and compliance with legacy 1N-series marking conventions.

Technical Context

This device operates as a two-terminal voltage reference diode, conducting in reverse breakdown to maintain stable output voltage across varying load currents. Its 3.0 V nominal zener voltage (min 2.85 V, max 3.15 V at 20 mA) and 29 Ω impedance ensure predictable regulation under low-current conditions.

The DO-35 glass package supports axial lead mounting with cathode indicated by a color band, and its absolute maximum ratings specify -65°C to +200°C operating/storage temperature range and 4.0 mW/°C linear derating above 75°C ambient.

Key Specifications

Parameter	Value and Actual Design Meaning
V_Z @ I_Z = 20 mA	2.85–3.15 V: Tight 5% tolerance enables accurate biasing in analog sensor interfaces and reference dividers.
Z_Z @ I_Z = 20 mA	29 Ω: Low dynamic impedance minimizes output voltage variation with load current changes.
I_ZM	120 mA: Maximum safe continuous Zener current defines upper limit for shunt regulator design headroom.
P_D @ T_L ≤ 75°C	500 mW: Power rating sets thermal boundary for PCB trace width and heatsinking in discrete regulator layouts.
Forward Voltage	≤1.5 V @ I_F = 200 mA: Confirms standard silicon PN junction behavior for forward-bias verification during functional test.
Reverse Leakage	50 µA @ V_R = 1 V: Low leakage preserves accuracy in high-impedance feedback networks.

Pinout & Package

DO-35 glass axial-leaded package with cathode identified by a single color band on the body. Leads are tinned copper-clad steel, 3/8″ length specified for thermal rating compliance.

Pin/Terminal	Circuit Role	Design Meaning
Anode	Forward conduction terminal / Zener breakdown return path	Connected to lower-potential node in shunt regulator; must handle full load current when regulating.
Cathode	Zener breakdown voltage reference terminal	Marked with color band; connected to regulated voltage rail; carries reverse current during regulation.

Key Features

Feature	Design Value
±5% Zener voltage tolerance	Enables direct replacement in legacy 1N-series designs without recalculating resistor values.
DO-35 glass package	Provides hermetic sealing and stable long-term voltage drift suitable for industrial-grade instrumentation.
500 mW power rating	Supports standalone shunt regulation up to ~160 mW delivered to load at 3.0 V with typical series resistor.
Cathode band marking	Ensures unambiguous polarity identification during manual assembly and automated optical inspection (AOI).

Applications

Industrial Sensor Biasing	Microcontroller Reset Threshold
Use Scenario: Providing stable 3.0 V reference for bridge sensor excitation in pressure transducers operating from 5 V rails. IC Role / Device Role / Timing Role: Zener diode acting as precision shunt voltage reference in ratiometric measurement circuitry. Use Value: 29 Ω impedance and 5% tolerance maintain <0.5% total error contribution to sensor output scaling.	Use Scenario: Generating clean reset threshold for 3.3 V microcontrollers where internal brown-out detection lacks sufficient hysteresis. IC Role / Device Role / Timing Role: Discrete voltage monitor enabling external reset assertion at precisely 3.0 V ±0.15 V. Use Value: Cathode-band polarity and DO-35 footprint allow drop-in integration into existing reset circuit layouts.
Low-Power Analog Reference	Overvoltage Clamp Protection
Use Scenario: Supplying reference voltage to op-amp-based signal conditioning stages in battery-powered data loggers. IC Role / Device Role / Timing Role: Passive voltage reference source for ADC input scaling and DAC output buffering. Use Value: 500 mW rating and -65°C to +200°C operating range support extended outdoor deployment without thermal derating concerns.	Use Scenario: Clamping transient spikes on 3.3 V I/O lines exposed to ESD or inductive switching noise. IC Role / Device Role / Timing Role: Fast-reacting shunt protector diverting surge current before IC damage occurs. Use Value: 120 mA I_ZM and 29 Ω Z_Z enable clamping within 10 ns of overvoltage onset while limiting clamp voltage to ≤3.3 V.

Industrial Sensor Biasing

Microcontroller Reset Threshold

Use Scenario: Providing stable 3.0 V reference for bridge sensor excitation in pressure transducers operating from 5 V rails.

IC Role / Device Role / Timing Role: Zener diode acting as precision shunt voltage reference in ratiometric measurement circuitry.

Use Value: 29 Ω impedance and 5% tolerance maintain <0.5% total error contribution to sensor output scaling.

Use Scenario: Generating clean reset threshold for 3.3 V microcontrollers where internal brown-out detection lacks sufficient hysteresis.

IC Role / Device Role / Timing Role: Discrete voltage monitor enabling external reset assertion at precisely 3.0 V ±0.15 V.

Use Value: Cathode-band polarity and DO-35 footprint allow drop-in integration into existing reset circuit layouts.

Low-Power Analog Reference

Overvoltage Clamp Protection

Use Scenario: Supplying reference voltage to op-amp-based signal conditioning stages in battery-powered data loggers.

IC Role / Device Role / Timing Role: Passive voltage reference source for ADC input scaling and DAC output buffering.

Use Value: 500 mW rating and -65°C to +200°C operating range support extended outdoor deployment without thermal derating concerns.

Use Scenario: Clamping transient spikes on 3.3 V I/O lines exposed to ESD or inductive switching noise.

IC Role / Device Role / Timing Role: Fast-reacting shunt protector diverting surge current before IC damage occurs.

Use Value: 120 mA I_ZM and 29 Ω Z_Z enable clamping within 10 ns of overvoltage onset while limiting clamp voltage to ≤3.3 V.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
1N4728A	Same 3.3 V nominal voltage but ±5% tolerance, 100 Ω Z_Z, 70 mA I_ZM, DO-41 package	Higher impedance and lower current rating reduce regulation stability in dynamic loads	Select only if DO-41 footprint compatibility is required and load current remains below 40 mA
BZX55C3V0	3.0 V ±5%, 90 Ω Z_Z, 50 mA I_ZM, DO-35 package, tighter tempco	Lower power rating limits use in sustained overvoltage clamping scenarios	Prefer for temperature-sensitive references where long-term drift matters more than surge handling

Compared with 1N4372A_T50R, the 1N4728A offers higher voltage but inferior regulation due to higher impedance and smaller package thermal mass, while the BZX55C3V0 matches voltage and package but sacrifices surge current capability-making 1N4372A_T50R optimal for robust, general-purpose 3.0 V shunt regulation.

Availability

1N4372A_T50R is available at Aetrix Electronics and suitable for industrial sensor biasing, microcontroller reset threshold generation, and low-power analog reference applications requiring stable component supply across multi-year production cycles.

Supply support for 1N4372A_T50R 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

Fairchild Semiconductor was a U.S.-based semiconductor company specializing in power management, analog, and discrete components before its acquisition by ON Semiconductor in 2016.

The 1N4372A_T50R belongs to Fairchild's legacy 1N-series Zener diode family, designed for general-purpose voltage regulation and reference in cost-sensitive, medium-reliability industrial and consumer electronics.

FAQ

What is the exact zener voltage range for 1N4372A_T50R at 20 mA test current?

The 1N4372A_T50R has a guaranteed zener voltage range of 2.85 V to 3.15 V when measured at I_Z = 20 mA and T_A = 25°C. This 5% tolerance reflects the device's specification per Fairchild Rev. D1 datasheet and applies directly to the 1N4372A_T50R marking variant.

Does 1N4372A_T50R have a defined forward voltage specification?

Yes, the 1N4372A_T50R specifies a maximum forward voltage of 1.5 V at I_F = 200 mA. This parameter confirms standard silicon diode conduction behavior and is used during functional testing to verify anode-cathode continuity before reverse-bias operation.

How is the cathode identified on the 1N4372A_T50R DO-35 package?

The cathode of the 1N4372A_T50R is marked by a single color band on the glass body of the DO-35 package. This band aligns with Fairchild's standardized marking convention for 1N-series Zeners and must be oriented toward the higher-potential node in shunt regulator configurations.

What is the power derating behavior of 1N4372A_T50R above 75°C lead temperature?

The 1N4372A_T50R derates linearly at 4.0 mW/°C above a lead temperature of 75°C. At 100°C lead temperature, its usable power dissipation drops to 400 mW, and at 125°C it falls to 300 mW-critical for thermal design in enclosed or high-ambient environments.

Is 1N4372A_T50R suitable for use in automotive applications?

The 1N4372A_T50R is not qualified to AEC-Q101 or automotive-grade reliability standards. While its -65°C to +200°C operating range exceeds typical automotive under-hood temperatures, its legacy qualification level and lack of PPAP documentation make it unsuitable for safety-critical or production automotive systems.

1N4372A_T50R Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

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

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Voltage - Zener (Nom) (Vz):: 3 V

Tolerance:: ±5%

Power - Max:: 500 mW

Impedance (Max) (Zzt):: 29 Ohms

Current - Reverse Leakage @ Vr:: 50 µA @ 1 V

Voltage - Forward (Vf) (Max) @ If:: 1.5 V @ 200 mA

Operating Temperature:: -65°C ~ 200°C

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: DO-35

1N4372A_T50R FAQ

1.How can I place an order for 1N4372A_T50R through Aetrix?

Please submit a Request for Quotation (RFQ) for 1N4372A_T50R 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 1N4372A_T50R reliable?

The price and inventory of 1N4372A_T50R are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N4372A_T50R is usually 5 days.

3.What payment methods are accepted for 1N4372A_T50R?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N4372A_T50R transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 1N4372A_T50R?

1N4372A_T50R orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 1N4372A_T50R 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 1N4372A_T50R?

For technical support, including 1N4372A_T50R datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N4372A_T50R requirements.

6.How does Aetrix verify that 1N4372A_T50R is sourced from the original manufacturer or authorized distributors?

All 1N4372A_T50R 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 1N4372A_T50R meets industry standards.

7.What is the process for return or replacement of 1N4372A_T50R?

All 1N4372A_T50R units undergo pre-shipment inspection (PSI). If there is an issue with 1N4372A_T50R, 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 1N4372A_T50R part is unused and in its original packaging.

Return procedure for 1N4372A_T50R:

1.Submit a request within 90 days.

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

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