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

onsemi 1N4370A_T50A

Name: 1N4370A_T50A
Brand: onsemi
SKU: 1N4370A_T50A
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 1N4370A_T50A

Manufacturer:: onsemi

Category:: Single Zener Diodes

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

Datasheet:: 1N4370A_T50A.pdf

Description:: DIODE ZENER 2.4V 500MW DO35

Quantity:: RFQ Add To RFQ list

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Inventory:9,564

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Product details

Overview

1N4370A from Fairchild Semiconductor is a 2.4 V ±5% silicon Zener diode in DO-35 glass package, rated for 500 mW power dissipation at TL ≤ 75°C, with 30 Ω dynamic impedance at 20 mA and 100 µA reverse leakage at 1 V, used for precision voltage reference and overvoltage protection in low-power analog circuits.

For engineers reviewing the 1N4370A datasheet, pinout, applications, or equivalent options, key selection criteria include zener voltage tolerance (±5%), thermal derating (4.0 mW/°C above 75°C), cathode-band polarity marking, and DO-35 mechanical compatibility with legacy through-hole designs.

Technical Context

This device operates as a two-terminal voltage-regulating diode, relying on controlled reverse-biased avalanche breakdown. Its 2.4 V nominal zener voltage is specified at 20 mA test current, with typical dynamic impedance of 30 Ω and maximum 2.52 V upper limit under 5% tolerance.

The DO-35 glass package enables stable junction temperature control up to +200°C storage, with cathode identification via color band and top-marking sequence "F / 37 / 0A". Reverse leakage remains ≤100 µA at VR = 1 V and rises to 200 µA at 125°C ambient.

Key Specifications

Parameter	Value and Actual Design Meaning
V_Z @ I_Z = 20 mA	2.4 V (nominal); defines stable regulation point for biasing or clamping circuits
Tolerance	±5%; ensures voltage accuracy within 2.28–2.52 V at 25°C
Z_Z @ 20 mA	30 Ω (typical); determines output impedance and load regulation sensitivity
P_D @ T_L ≤ 75°C	500 mW; sets maximum continuous power handling before thermal derating applies
I_R @ V_R = 1 V	≤100 µA at 25°C; confirms low leakage in standby or high-impedance sensing paths
Package	DO-35 glass; provides hermetic sealing, axial leads, and industry-standard footprint
Operating Temp	–65°C to +200°C; supports extended-range industrial and automotive under-hood use

Pinout & Package

DO-35 glass axial-leaded package with cathode identified by a single color band near one lead end. Leads are tinned copper-clad steel, 3/8″ length standard for thermal rating compliance.

Pin/Terminal	Circuit Role	Design Meaning
Anode	Forward conduction terminal	Connected to lower-potential node during forward bias; not used in zener regulation mode
Cathode	Zener breakdown terminal	Connected to higher-potential node; voltage referenced to this terminal during reverse operation

Key Features

Feature	Design Value
±5% V_Z tolerance	Enables predictable regulation without post-production trimming in cost-sensitive analog references
DO-35 glass construction	Provides hermeticity and long-term stability for high-reliability applications requiring >10-year shelf life
500 mW power rating	Supports direct replacement of older 1/2 W zeners without board redesign or heatsinking
Cathode band marking	Ensures unambiguous polarity identification during manual assembly and automated optical inspection

Applications

Voltage Reference for Op-Amp Biasing	Overvoltage Clamp in Sensor Interface
Use Scenario: Stable 2.4 V reference for rail-to-rail op-amp input bias networks in battery-powered instrumentation. IC Role / Device Role / Timing Role: Zener diode providing fixed reference potential independent of supply variation. Use Value: Maintains <±10 mV drift over –40°C to +85°C due to tight 5% tolerance and low Z_Z.	Use Scenario: Protection circuit limiting sensor output swing to prevent ADC saturation in 3.3 V systems. IC Role / Device Role / Timing Role: Shunt clamp activated when transient exceeds 2.52 V (V_Z max). Use Value: Absorbs up to 150 mA peak surge (IZM) without degradation, per absolute max ratings.
Low-Power Microcontroller Reset Threshold	Legacy TTL Logic Level Translation
Use Scenario: Brown-out detection threshold set at 2.4 V for 8-bit MCUs operating from 3 V coin cells. IC Role / Device Role / Timing Role: Voltage-sensing element triggering reset generator IC when V_CC falls below regulation point. Use Value: Delivers consistent trip point across temperature with <0.5%/°C TC, verified in datasheet curves.	Use Scenario: Converting 5 V logic high to 2.4 V compatible level for interfacing with older 3 V logic families. IC Role / Device Role / Timing Role: Passive level shifter using forward drop (1.5 V max) and zener clamp action. Use Value: Achieves clean transition with <10 ns response time due to low junction capacitance (<2 pF, inferred from DO-35 geometry).

Voltage Reference for Op-Amp Biasing

Overvoltage Clamp in Sensor Interface

Use Scenario: Stable 2.4 V reference for rail-to-rail op-amp input bias networks in battery-powered instrumentation.

IC Role / Device Role / Timing Role: Zener diode providing fixed reference potential independent of supply variation.

Use Value: Maintains <±10 mV drift over –40°C to +85°C due to tight 5% tolerance and low Z_Z.

Use Scenario: Protection circuit limiting sensor output swing to prevent ADC saturation in 3.3 V systems.

IC Role / Device Role / Timing Role: Shunt clamp activated when transient exceeds 2.52 V (V_Z max).

Use Value: Absorbs up to 150 mA peak surge (IZM) without degradation, per absolute max ratings.

Low-Power Microcontroller Reset Threshold

Legacy TTL Logic Level Translation

Use Scenario: Brown-out detection threshold set at 2.4 V for 8-bit MCUs operating from 3 V coin cells.

IC Role / Device Role / Timing Role: Voltage-sensing element triggering reset generator IC when V_CC falls below regulation point.

Use Value: Delivers consistent trip point across temperature with <0.5%/°C TC, verified in datasheet curves.

Use Scenario: Converting 5 V logic high to 2.4 V compatible level for interfacing with older 3 V logic families.

IC Role / Device Role / Timing Role: Passive level shifter using forward drop (1.5 V max) and zener clamp action.

Use Value: Achieves clean transition with <10 ns response time due to low junction capacitance (<2 pF, inferred from DO-35 geometry).

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
1N4728A (ON Semiconductor)	Same 3.3 V nominal rating but different V_Z range (3.14–3.47 V); 1.0 W power rating	Higher power handling unsuitable for space-constrained 500 mW designs	Select only if board layout allows larger heat dissipation and voltage tolerance budget permits 3.3 V vs. 2.4 V
BZX55-C2V4 (Vishay)	Same 2.4 V nominal, ±5% tolerance, DO-35 package; 500 mW rating; tighter Z_Z spec (25 Ω max)	Identical electrical and mechanical fit; minor differences in leakage (50 µA max @ 1 V)	Drop-in alternative with improved consistency in production lots and RoHS-compliant materials

Compared with 1N4370A, the BZX55-C2V4 offers lower leakage and tighter impedance control for high-precision references, while the 1N4728A serves higher-power 3.3 V regulation needs - neither is pin-compatible without verifying voltage and thermal requirements.

Availability

1N4370A is available at Aetrix Electronics and suitable for voltage reference, overvoltage protection, and brown-out detection applications requiring stable component supply across industrial control, sensor signal conditioning, and legacy embedded systems.

Supply support for 1N4370A 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 designer of high-performance analog and discrete semiconductors, acquired by ON Semiconductor in 2016; known for robust, industry-standard devices with broad second-source availability.

The 1N4370A belongs to Fairchild's legacy 1Nxx Zener series designed for general-purpose voltage regulation in cost-sensitive, through-hole assembled equipment where reliability and interchangeability are critical.

FAQ

What is the exact zener voltage tolerance for 1N4370A?

The 1N4370A has a guaranteed ±5% zener voltage tolerance at 20 mA test current and 25°C ambient, resulting in a specification range of 2.28 V to 2.52 V. This tolerance is maintained across the full operating temperature range per the manufacturer's published derating curves and is verified during final test screening.

Can 1N4370A be used in surface-mount designs?

No, the 1N4370A is exclusively packaged in the axial-leaded DO-35 glass case and requires through-hole mounting. It lacks SMD variants such as SOD-123 or DO-213AA. For surface-mount equivalents, consider the BZX55-C2V4 in DO-35 or BZT52-B2V4 in SOD-123, both offering matching 2.4 V regulation.

What is the maximum reverse leakage current for 1N4370A at elevated temperature?

At 125°C ambient, the 1N4370A exhibits up to 200 µA reverse leakage current when biased at VR = 1 V, per the datasheet's "IR vs. Temperature" table. This value doubles from the 25°C rating (100 µA), reflecting expected thermal behavior for silicon Zeners.

Does 1N4370A have a specified forward voltage?

Yes, the 1N4370A has a maximum forward voltage of 1.5 V at IF = 200 mA, as stated in the "VF Forward Voltage" note. This parameter is relevant when the device is used in forward-conduction mode, such as in level-shifting or LED-driving configurations where anode-cathode polarity is reversed from normal zener operation.

How is cathode polarity marked on the 1N4370A package?

The cathode of the 1N4370A is marked by a single color band located near one lead end of the DO-35 glass body. Additionally, the top marking shows "F / 37 / 0A", where "0A" identifies the specific variant and confirms cathode orientation per Fairchild's marking standard.

1N4370A_T50A Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

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

Packaging:: Tape & Box (TB)

Product Status:: Obsolete

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:: 1.5 V @ 200 mA

Operating Temperature:: -65°C ~ 200°C

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: DO-35

1N4370A_T50A FAQ

1.How can I place an order for 1N4370A_T50A through Aetrix?

Please submit a Request for Quotation (RFQ) for 1N4370A_T50A 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 1N4370A_T50A reliable?

The price and inventory of 1N4370A_T50A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N4370A_T50A is usually 5 days.

3.What payment methods are accepted for 1N4370A_T50A?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N4370A_T50A transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 1N4370A_T50A?

1N4370A_T50A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 1N4370A_T50A 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 1N4370A_T50A?

For technical support, including 1N4370A_T50A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N4370A_T50A requirements.

6.How does Aetrix verify that 1N4370A_T50A is sourced from the original manufacturer or authorized distributors?

All 1N4370A_T50A 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 1N4370A_T50A meets industry standards.

7.What is the process for return or replacement of 1N4370A_T50A?

All 1N4370A_T50A units undergo pre-shipment inspection (PSI). If there is an issue with 1N4370A_T50A, 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 1N4370A_T50A part is unused and in its original packaging.

Return procedure for 1N4370A_T50A:

1.Submit a request within 90 days.

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

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