1N4449 Equivalent & Substitute Parts

Part Overview

The 1N4449 is a general-purpose small-signal diode manufactured by Microchip Technology, rated for 75 V DC reverse voltage and 200 mA average rectified current in a DO-35 through-hole package. This part is discontinued at DiGi Electronics, making equivalent substitutes necessary for ongoing design and production requirements. The 1N4449 operates across a junction temperature range of -65°C to 150°C and exhibits a reverse recovery time of 4 ns with low reverse leakage characteristics of 25 nA at 20 V.

Key Parameters

Parameter	Value	Unit
Voltage - DC Reverse (Vr) (Max)	75	V
Current - Average Rectified (Io)	200	mA
Voltage - Forward (Vf) (Max) @ If	1 V @ 30 mA	V
Reverse Recovery Time (trr)	4	ns
Current - Reverse Leakage @ Vr	25 nA @ 20 V	nA
Mounting Type	Through Hole	—
Package / Case	DO-204AH, DO-35, Axial	—
Operating Temperature - Junction	-65 to 150	°C
Technology	Standard	—
Speed	Small Signal ≤ 200mA (Io), Any Speed	—

Substitute Part Grouping Explanation

Substitution of the 1N4449 is determined by compatibility across the following critical parameters:

Mandatory Compatibility Criteria:

Mounting Type: Through Hole
Package / Case: DO-35 (DO-204AH) Axial
Technology: Standard small-signal diode
Speed Classification: Small Signal ≤ 200mA (Io), Any Speed
Voltage - DC Reverse (Vr) (Max): Must equal or exceed 75 V
Current - Average Rectified (Io): Must equal or exceed 200 mA
Reverse Recovery Time (trr): 4 ns
Operating Temperature Range: Must accommodate application requirements

Substitute parts are grouped into two categories based on voltage and current ratings:

Category A - Direct Electrical Equivalents (100 V, 200 mA): Parts with higher voltage ratings (100 V) and matching or higher current capacity (200 mA) provide direct substitution with enhanced voltage margin. These include 1N4148-T26A, 1N4148-T50A, 1N4148-T50R, 1N4148TA, and 1N4148TR.

Category B - Functional Equivalents (70 V, 200 mA or 100 V, 150 mA): Parts with voltage ratings near or slightly above 75 V, or current ratings at 150 mA, function as substitutes in applications where the full 200 mA capacity is not required. These include 1N457, 1N457A, 1N4148, and 1N4448TR.

Category C - Reduced Voltage Equivalents (50 V, 200 mA): The 1N4454TR operates at 50 V maximum reverse voltage and is suitable only for applications where the circuit voltage does not exceed 50 V.

Parameter Comparison

Part Number	Manufacturer	Vr (Max) [V]	Io [mA]	Vf (Max) @ If [V]	trr [ns]	Ir @ Vr [nA/µA]	Tj (Max) [°C]	Product Status
1N4449	Microchip Technology	75	200	1 @ 30 mA	4	25 nA @ 20 V	150	Discontinued
1N4148	Taiwan Semiconductor Corporation	100	150	1 @ 10 mA	4	5 µA @ 75 V	150	Active
1N4148-T26A	onsemi	100	200	1 @ 10 mA	4	5 µA @ 75 V	175	Active
1N4148-T50A	Fairchild Semiconductor	100	200	1 @ 10 mA	4	5 µA @ 75 V	175	Active
1N4148-T50R	onsemi	100	200	1 @ 10 mA	4	5 µA @ 75 V	175	Active
1N4148TA	Fairchild Semiconductor	100	200	1 @ 10 mA	4	5 µA @ 75 V	175	Active
1N4148TR	Fairchild Semiconductor	100	200	1 @ 10 mA	4	5 µA @ 75 V	175	Active
1N4448TR	Vishay General Semiconductor - Diodes Division	100	150	1 @ 100 mA	8	5 µA @ 75 V	175	Active
1N4454TR	onsemi	50	200	1 @ 10 mA	4	100 nA @ 50 V	175	Active
1N457	Fairchild Semiconductor	70	200	1 @ 20 mA	4	25 nA @ 60 V	175	Active
1N457A	Microchip Technology	70	150	1 @ 100 mA	4	1 µA @ 70 V	150	Active

Engineering Selection Recommendations

Primary Substitutes (Recommended for Direct Replacement):

The 1N4148-T26A, 1N4148-T50A, 1N4148-T50R, 1N4148TA, and 1N4148TR are the preferred substitutes for the 1N4449. These parts maintain the 200 mA current rating and provide a 100 V reverse voltage rating, exceeding the original 75 V specification. All are active products with ROHS3 compliance and REACH unaffected status. The higher voltage rating provides additional design margin without compromising performance. Inventory availability is substantial across all variants.

Secondary Substitutes (Application-Dependent):

The 1N457 is suitable for applications requiring the original 75 V voltage class with 200 mA current capacity. This part is active and maintains the 4 ns reverse recovery time. The 1N457A operates at 70 V with 150 mA current and is available from Microchip Technology, the original 1N4449 manufacturer.

The 1N4148 (Taiwan Semiconductor Corporation) operates at 100 V but is rated for 150 mA average rectified current. This part is suitable only for applications where the circuit current does not exceed 150 mA.

Not Recommended:

The 1N4454TR is rated for only 50 V maximum reverse voltage and is unsuitable for circuits designed for the 75 V rating of the 1N4449.

The 1N4448TR exhibits an 8 ns reverse recovery time, which differs from the 4 ns specification of the 1N4449 and may affect circuit timing in applications sensitive to switching speed.

Frequently Asked Questions (FAQ)

Q: Can the 1N4148-T50R directly replace the 1N4449 in all applications?

A: The 1N4148-T50R is electrically compatible with the 1N4449 for applications operating at or below 75 V. The part is rated for 100 V reverse voltage and 200 mA average rectified current, meeting or exceeding all electrical requirements of the 1N4449. Both parts use the DO-35 through-hole package and exhibit identical 4 ns reverse recovery time. The primary difference is the higher maximum junction temperature (175°C vs. 150°C) of the 1N4148-T50R, which provides additional thermal margin.

Q: What is the difference between the various 1N4148 variants (1N4148-T26A, 1N4148-T50A, 1N4148-T50R, 1N4148TA, 1N4148TR)?

A: These variants represent different packaging and tape configurations from multiple manufacturers. The electrical specifications are identical: 100 V reverse voltage, 200 mA average rectified current, 1 V forward voltage at 10 mA, and 4 ns reverse recovery time. The suffix designations indicate packaging format (tape, bulk, cut tape) and manufacturer-specific part numbering. Selection among these variants depends on procurement requirements and packaging preferences rather than electrical performance.

Q: Is the 1N457 a suitable substitute for the 1N4449?

A: The 1N457 is suitable for applications requiring the original 75 V voltage specification with 200 mA current capacity. The 1N457 is rated for 70 V reverse voltage and 200 mA average rectified current, providing functional equivalence. Both parts exhibit 4 ns reverse recovery time and use the DO-35 through-hole package. The 1N457 is an active product with higher maximum junction temperature (175°C vs. 150°C).

Q: Why does the 1N4148 have lower current rating (150 mA) than the 1N4449 (200 mA)?

A: The 1N4148 is rated for 150 mA average rectified current, which is lower than the 1N4449 specification of 200 mA. The 1N4148 is suitable only for applications where the circuit current does not exceed 150 mA. For applications requiring the full 200 mA capacity, use 1N4148-T26A, 1N4148-T50A, 1N4148-T50R, 1N4148TA, or 1N4148TR instead.

Q: Can the 1N4454TR replace the 1N4449?

A: The 1N4454TR is not recommended as a substitute for the 1N4449. The 1N4454TR is rated for only 50 V maximum reverse voltage, which is significantly lower than the 1N4449 specification of 75 V. Use of the 1N4454TR in a circuit designed for 75 V operation will result in diode failure. The 1N4454TR is suitable only for applications where the circuit voltage does not exceed 50 V.

Q: What is the significance of reverse recovery time (trr) in diode substitution?

A: Reverse recovery time is the interval required for a diode to transition from forward conduction to reverse blocking when the applied voltage reverses. The 1N4449 specifies 4 ns reverse recovery time. Substitute parts with identical or faster (lower) reverse recovery time maintain circuit switching characteristics. The 1N4448TR exhibits 8 ns reverse recovery time, which is slower than the 1N4449 and may affect circuit timing in applications sensitive to switching speed.

Q: Are all substitute parts RoHS compliant?

A: The 1N4449 is RoHS non-compliant. Most active substitute parts, including 1N4148-T26A, 1N4148-T50A, 1N4148-T50R, 1N4148TA, 1N4148TR, 1N4448TR, and 1N4454TR, are ROHS3 compliant. The 1N457A from Microchip Technology is RoHS non-compliant, matching the original part status. Compliance requirements should be verified against specific application and regulatory standards.

Q: What is the difference between DO-35 and DO-204AH package designations?

A: DO-35 and DO-204AH are equivalent package designations for the same through-hole axial diode package. Both refer to a cylindrical component with axial leads suitable for through-hole mounting on printed circuit boards. All substitute parts listed use this identical package format and are mechanically interchangeable with the 1N4449.

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