1N4944-AP Equivalent & Substitute Parts

Part Overview

The 1N4944-AP is a general-purpose rectifier diode rated for 400 V DC reverse voltage and 1 A average rectified current in a DO-41 through-hole package. Manufactured by Micro Commercial Co, this part is classified as obsolete. Equivalent and substitute parts are necessary to maintain design continuity and ensure component availability for new production and repair applications. Substitute parts must maintain electrical compatibility across voltage, current, and thermal specifications while accommodating packaging and sourcing variations.

Key Parameters

Parameter	Value	Unit
Voltage - DC Reverse (Vr) (Max)	400	V
Current - Average Rectified (Io)	1	A
Voltage - Forward (Vf) (Max) @ If	1.3	V @ 1 A
Reverse Recovery Time (trr)	150	ns
Current - Reverse Leakage @ Vr	5	µA @ 400 V
Mounting Type	Through Hole	-
Package / Case	DO-204AL, DO-41, Axial	-
Operating Temperature - Junction	-55 to 150	°C
Technology	Standard	-
RoHS Status	ROHS3 Compliant	-

Substitute Part Grouping Explanation

Substitute parts for the 1N4944-AP are classified into two categories based on electrical and mechanical compatibility:

Direct Substitutes (Parametric Equivalents): Parts that maintain identical or equivalent electrical specifications across all critical parameters: 400 V reverse voltage, 1 A average rectified current, 1.3 V forward voltage at 1 A, 150 ns reverse recovery time, and DO-41 through-hole mounting. These parts are interchangeable in circuit applications without design modification.

Similar Substitutes (Higher Current Rating): Parts that exceed the 1 A current specification while maintaining 400 V reverse voltage and DO-41 packaging. These parts provide enhanced current capacity and are suitable for applications requiring higher current margins.

The following parameters determine substitution eligibility:

Voltage - DC Reverse (Vr) (Max): Must equal or exceed 400 V
Current - Average Rectified (Io): Must equal or exceed 1 A
Mounting Type: Through Hole
Package / Case: DO-204AL, DO-41, or Axial
Operating Temperature Range: Must encompass -55°C to 150°C junction temperature

Parameter Comparison

Part Number	Manufacturer	Product Status	Vr (Max) [V]	Io [A]	Vf (Max) @ If [V]	trr [ns]	Ir @ Vr [µA]	Package	Temp Range [°C]
1N4944-AP	Micro Commercial Co	Obsolete	400	1	1.3 @ 1 A	150	5 @ 400 V	DO-41	-55 to 150
1N4944GP-AP	Micro Commercial Co	Active	400	1	1.3 @ 1 A	150	5 @ 400 V	DO-41	-55 to 150
1N4936GP-AP	Micro Commercial Co	Active	400	1	1.2 @ 1 A	200	5 @ 400 V	DO-41	-55 to 150
FR104GP-AP	Micro Commercial Co	Active	400	1	1.3 @ 1 A	150	5 @ 400 V	DO-41	-55 to 150
SF16G-AP	Micro Commercial Co	Active	400	1	1.3 @ 1 A	35	5 @ 400 V	DO-41	-55 to 150
UF4004GP-AP	Micro Commercial Co	Active	400	1	1.3 @ 1 A	50	5 @ 400 V	DO-41	-55 to 150
FR104A-G	Comchip Technology	Active	400	1	1.3 @ 1 A	150	5 @ 400 V	DO-41	-55 to 150
FR104G A0G	Taiwan Semiconductor Corporation	Active	400	1	1.3 @ 1 A	150	5 @ 400 V	DO-41	-55 to 150
HER105G A0G	Taiwan Semiconductor Corporation	Active	400	1	1.3 @ 1 A	50	5 @ 400 V	DO-41	-55 to 150
MUR240G	onsemi	Obsolete	400	2	1.3 @ 2 A	65	5 @ 400 V	Axial	-65 to 175
MUR240RLG	onsemi	Active	400	2	1.3 @ 2 A	65	5 @ 400 V	Axial	-65 to 175

Engineering Selection Recommendations

Direct Substitution (Preferred): The 1N4944GP-AP is the primary direct substitute for the obsolete 1N4944-AP. Both parts are manufactured by Micro Commercial Co and maintain identical electrical specifications across all critical parameters. The 1N4944GP-AP is active in production status, ensuring long-term availability. This part requires no circuit design modification and provides pin-for-pin compatibility.

Alternative Direct Substitutes: FR104GP-AP, FR104A-G, and FR104G A0G are parametric equivalents with identical voltage, current, and temperature specifications. These parts are manufactured by Micro Commercial Co, Comchip Technology, and Taiwan Semiconductor Corporation respectively, all with active product status. Selection among these alternatives depends on packaging preference (Tape & Box or Cut Tape) and supplier availability.

Enhanced Performance Alternatives: SF16G-AP and UF4004GP-AP provide faster reverse recovery times (35 ns and 50 ns respectively) compared to the original 150 ns specification. These parts maintain all other electrical parameters and are suitable for applications requiring improved switching performance. HER105G A0G similarly offers 50 ns reverse recovery time with active product status from Taiwan Semiconductor Corporation.

Higher Current Capacity: MUR240RLG (onsemi, active status) provides 2 A average rectified current while maintaining 400 V reverse voltage. This part is suitable for applications requiring current margin above the 1 A specification. The axial package configuration differs from the original DO-41 package and requires mechanical board layout consideration.

Compliance Verification: All recommended substitutes maintain ROHS3 compliance and EAR99 export classification consistent with the original part. Moisture Sensitivity Level (MSL) is rated as 1 (Unlimited) for all direct substitutes, indicating no special moisture handling requirements.

Frequently Asked Questions (FAQ)

Q: Can the 1N4944GP-AP directly replace the obsolete 1N4944-AP without circuit modification?

A: Yes. The 1N4944GP-AP is a direct parametric equivalent with identical voltage (400 V), current (1 A), forward voltage (1.3 V @ 1 A), and reverse recovery time (150 ns) specifications. Both parts use DO-41 through-hole packaging and operate across the same temperature range (-55°C to 150°C). No circuit design changes are required.

Q: What is the difference between FR104GP-AP and FR104G A0G?

A: Both parts are parametric equivalents with identical electrical specifications (400 V, 1 A, 1.3 V forward voltage, 150 ns reverse recovery time). The primary differences are manufacturer (Micro Commercial Co versus Taiwan Semiconductor Corporation) and packaging format (Tape & Box versus Cut Tape). Electrical performance in circuit applications is equivalent.

Q: Can I use MUR240RLG as a substitute for the 1N4944-AP?

A: MUR240RLG is electrically compatible with the 1N4944-AP for voltage and current specifications (400 V, 2 A rating). However, the MUR240RLG uses axial through-hole packaging rather than the DO-41 package of the original part. Board layout and mechanical mounting must be verified for compatibility. The higher 2 A current rating provides additional margin for applications requiring increased current capacity.

Q: What does reverse recovery time (trr) mean, and why does it vary among substitutes?

A: Reverse recovery time is the interval required for a diode to transition from forward conduction to reverse blocking when the applied voltage reverses polarity. The 1N4944-AP specifies 150 ns. Substitutes such as SF16G-AP (35 ns) and UF4004GP-AP (50 ns) offer faster recovery, which reduces switching losses and improves efficiency in high-frequency applications. Slower recovery times (such as 200 ns in 1N4936GP-AP) are acceptable for lower-frequency applications.

Q: Are all substitute parts RoHS compliant?

A: Yes. All recommended substitute parts maintain ROHS3 compliance, consistent with the original 1N4944-AP specification. This compliance status applies to all direct substitutes and similar alternatives listed in this reference.

Q: What is the significance of the DO-41 package designation?

A: DO-41 (also designated DO-204AL) is a through-hole axial package format with two leads suitable for manual or automated insertion into printed circuit boards. All direct substitutes maintain this package format, ensuring mechanical and electrical compatibility with existing board designs. The MUR240RLG uses the same DO-41 axial package but with higher current rating.

Q: Can I substitute parts with different forward voltage specifications?

A: The 1N4944-AP specifies 1.3 V maximum forward voltage at 1 A. The 1N4936GP-AP offers 1.2 V maximum forward voltage, which is lower and acceptable for most applications. Lower forward voltage reduces power dissipation and heat generation. Higher forward voltage specifications would increase power loss and are not recommended as substitutes.

Q: What does MSL 1 (Unlimited) mean for moisture sensitivity?

A: MSL 1 (Unlimited) indicates that the component has no moisture sensitivity limitations. These parts do not require special moisture-controlled storage or handling procedures. Standard storage conditions are sufficient, simplifying inventory management and reducing component preparation time before assembly.

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