HER304-AP Equivalent & Substitute Parts

Part Overview

The HER304-AP is a general-purpose rectifier diode manufactured by Micro Commercial Co, rated for 300 V DC reverse voltage and 3 A average rectified current in a DO-201AD axial through-hole package. This part is classified as obsolete, making identification of active equivalent and substitute components necessary for ongoing design support and procurement.

Key Parameters

Parameter	Value
Voltage - DC Reverse (Vr) (Max)	300 V
Current - Average Rectified (Io)	3 A
Voltage - Forward (Vf) (Max) @ If	1.3 V @ 3 A
Speed	Fast Recovery ≤ 500ns, > 200mA (Io)
Reverse Recovery Time (trr)	50 ns
Current - Reverse Leakage @ Vr	10 µA @ 300 V
Package / Case	DO-201AD, Axial
Mounting Type	Through Hole
Operating Temperature - Junction	-55°C ~ 150°C
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitute parts for the HER304-AP are grouped based on electrical and mechanical parameter compatibility within the rectifier diode category. The primary substitution criteria are:

Critical Parameters for Substitution:

Voltage - DC Reverse (Vr) (Max): 300 V
Current - Average Rectified (Io): 3 A
Package / Case: DO-201AD, Axial
Mounting Type: Through Hole
Operating Temperature Range: -55°C ~ 150°C

Secondary Parameters Affecting Performance:

Voltage - Forward (Vf) (Max) @ If
Reverse Recovery Time (trr)
Current - Reverse Leakage @ Vr
Capacitance @ Vr, F

All substitute parts listed maintain the critical electrical ratings and physical package specifications required for direct replacement in applications designed for the HER304-AP. Variations in forward voltage, reverse recovery time, and leakage current remain within acceptable ranges for general-purpose rectification applications.

Parameter Comparison

Parameter	HER304-AP	HER304G-AP	SF35G A0G	SF35GHA0G
Manufacturer	Micro Commercial Co	Micro Commercial Co	Taiwan Semiconductor Corporation	Taiwan Semiconductor Corporation
Product Status	Obsolete	Active	Active	Active
Voltage - DC Reverse (Vr) (Max)	300 V	300 V	300 V	300 V
Current - Average Rectified (Io)	3 A	3 A	3 A	3 A
Voltage - Forward (Vf) (Max) @ If	1.3 V @ 3 A	950 mV @ 3 A	1.3 V @ 3 A	1.3 V @ 3 A
Reverse Recovery Time (trr)	50 ns	50 ns	35 ns	35 ns
Current - Reverse Leakage @ Vr	10 µA @ 300 V	10 µA @ 300 V	5 µA @ 300 V	5 µA @ 300 V
Capacitance @ Vr, F	80pF @ 4V, 1MHz	80pF @ 4V, 1MHz	60pF @ 4V, 1MHz	60pF @ 4V, 1MHz
Package / Case	DO-201AD, Axial	DO-201AD, Axial	DO-201AD, Axial	DO-201AD, Axial
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole
Operating Temperature - Junction	-55°C ~ 150°C	-55°C ~ 150°C	-55°C ~ 150°C	-55°C ~ 150°C
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Grade	Standard	Standard	Standard	Automotive
Qualification	—	—	—	AEC-Q101

Engineering Selection Recommendations

HER304G-AP (Micro Commercial Co)

The HER304G-AP is the direct successor to the obsolete HER304-AP from the same manufacturer. This part maintains identical electrical ratings and package specifications while offering active product status. The HER304G-AP features improved forward voltage performance at 950 mV compared to the original 1.3 V specification, resulting in lower power dissipation. This part is ROHS3 compliant and carries unlimited moisture sensitivity level classification.

SF35G A0G (Taiwan Semiconductor Corporation)

The SF35G A0G is a parametric equivalent offering 300 V / 3 A rectification in the DO-201AD package. This part provides improved reverse recovery time of 35 ns and reduced reverse leakage current of 5 µA, compared to the original 50 ns and 10 µA specifications. Lower capacitance of 60pF also supports higher-frequency applications. Active product status and ROHS3 compliance are confirmed.

SF35GHA0G (Taiwan Semiconductor Corporation)

The SF35GHA0G is an automotive-grade variant of the SF35G A0G, qualified to AEC-Q101 standard. Electrical and thermal specifications remain identical to the SF35G A0G. This part is suitable for applications requiring automotive-grade component certification and traceability.

Frequently Asked Questions (FAQ)

Q: Can the HER304G-AP be used as a direct replacement for the HER304-AP?

A: Yes. The HER304G-AP maintains identical voltage, current, and package specifications. Both parts are rated for 300 V reverse voltage, 3 A average rectified current, and use the DO-201AD axial through-hole package. The HER304G-AP is the active production equivalent.

Q: What are the differences between the Taiwan Semiconductor Corporation parts and the Micro Commercial Co parts?

A: The SF35G A0G and SF35GHA0G offer improved reverse recovery time (35 ns versus 50 ns) and lower reverse leakage current (5 µA versus 10 µA). Forward voltage remains at 1.3 V. The SF35GHA0G adds automotive-grade qualification (AEC-Q101) for applications requiring this certification.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All listed substitute parts carry ROHS3 compliance certification, matching the original HER304-AP specification.

Q: Can the SF35GHA0G be used in non-automotive applications?

A: Yes. The SF35GHA0G meets or exceeds all electrical and thermal specifications required for general-purpose rectification. Automotive qualification does not restrict use in other applications.

Q: What is the significance of the reverse recovery time difference between parts?

A: Reverse recovery time affects switching speed and switching losses in high-frequency applications. The SF35G A0G and SF35GHA0G offer 35 ns recovery time compared to 50 ns in the original and HER304G-AP, enabling operation at higher switching frequencies with reduced power dissipation.

Q: Are the forward voltage differences significant for circuit design?

A: Forward voltage differences affect power dissipation and voltage drop across the diode. The HER304G-AP at 950 mV provides lower dissipation than the original 1.3 V specification. The SF35G A0G and SF35GHA0G maintain the original 1.3 V specification. Circuit designs should account for these differences in thermal and voltage drop calculations.

Q: Is the DO-201AD package identical across all substitute parts?

A: Yes. All parts use the DO-201AD axial through-hole package with identical physical dimensions and pin configuration, enabling direct mechanical substitution on printed circuit boards.

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