HER104S-AP Equivalent & Substitute Parts

Part Overview

The HER104S-AP is a general-purpose rectifier diode rated for 300 V DC reverse voltage and 1 A average rectified current. Manufactured by Micro Commercial Co, this component features fast recovery characteristics with a reverse recovery time of 50 ns, making it suitable for standard rectification applications in power supply and signal conditioning circuits.

The HER104S-AP is classified as obsolete. Locating equivalent substitute parts is necessary to support ongoing production requirements, field repairs, and design updates where this component is specified.

Key Parameters

Parameter	Value	Unit
Voltage - DC Reverse (Vr) (Max)	300	V
Current - Average Rectified (Io)	1	A
Voltage - Forward (Vf) (Max) @ If	1	V @ 1 A
Reverse Recovery Time (trr)	50	ns
Current - Reverse Leakage @ Vr	5	mA @ 300 V
Mounting Type	Through Hole	—
Package / Case	Axial	—
Operating Temperature - Junction	-55 to 125	°C
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitute parts for the HER104S-AP are identified based on electrical and mechanical parameter equivalence within the rectifier diode category. The substitution logic is based on the following criteria:

Electrical Parameters (Must Match):

Voltage - DC Reverse (Vr) (Max): 300 V
Current - Average Rectified (Io): 1 A
Voltage - Forward (Vf) (Max) @ If: 1 V @ 1 A
Reverse Recovery Time (trr): 50 ns
Operating Temperature - Junction: -55°C to 125°C

Mechanical Parameters (Must Match):

Mounting Type: Through Hole
Package / Case: Axial or equivalent axial package designation

Compliance Parameters (Must Match):

RoHS Status: ROHS3 Compliant
Technology: Standard

The HER104G-AP meets all specified electrical and mechanical parameters and is classified as an active product, making it a direct substitute for the obsolete HER104S-AP.

Parameter Comparison

Parameter	HER104S-AP	HER104G-AP	Match
Voltage - DC Reverse (Vr) (Max)	300 V	300 V	✓
Current - Average Rectified (Io)	1 A	1 A	✓
Voltage - Forward (Vf) (Max) @ If	1 V @ 1 A	1 V @ 1 A	✓
Speed	Fast Recovery ≤ 500ns, > 200mA (Io)	Fast Recovery ≤ 500ns, > 200mA (Io)	✓
Reverse Recovery Time (trr)	50 ns	50 ns	✓
Current - Reverse Leakage @ Vr	5 mA @ 300 V	5 µA @ 300 V	Compatible*
Capacitance @ Vr, F	20 pF @ 4V, 1MHz	20 pF @ 4V, 1MHz	✓
Mounting Type	Through Hole	Through Hole	✓
Package / Case	Axial (A-405)	Axial (DO-41, DO-204AL)	✓
Operating Temperature - Junction	-55°C to 125°C	-55°C to 125°C	✓
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	✓
Product Status	Obsolete	Active	—

*Note: HER104G-AP exhibits lower reverse leakage current (5 µA vs. 5 mA), which represents improved performance and is acceptable for substitution.

Engineering Selection Recommendations

The HER104G-AP is the direct substitute for the HER104S-AP based on the following factors:

Electrical Equivalence: All critical electrical parameters match exactly, including reverse voltage rating, average rectified current, forward voltage drop, and reverse recovery time. The HER104G-AP demonstrates superior reverse leakage characteristics (5 µA vs. 5 mA), indicating improved device quality without compromising circuit performance.

Mechanical Compatibility: Both devices employ through-hole axial mounting and are compatible with standard PCB layouts designed for the HER104S-AP. The DO-41 package designation of the HER104G-AP is the industry-standard successor to the A-405 package.

Compliance Status: The HER104G-AP maintains ROHS3 compliance and carries REACH Unaffected status, ensuring regulatory alignment with current manufacturing standards.

Product Availability: The HER104G-AP is classified as an active product with confirmed inventory availability (1155 pieces), whereas the HER104S-AP is obsolete. This availability difference makes the HER104G-AP the practical choice for new production and field replacement applications.

Frequently Asked Questions (FAQ)

Q: Can the HER104G-AP be used as a direct replacement for the HER104S-AP in existing circuit designs?

A: Yes. The HER104G-AP is electrically and mechanically equivalent to the HER104S-AP. Both devices share identical voltage ratings, current ratings, forward voltage characteristics, and reverse recovery time. The through-hole axial package format is compatible with existing PCB layouts.

Q: What is the difference between the A-405 and DO-41 package designations?

A: Both designations refer to axial through-hole packages for rectifier diodes. The DO-41 (DO-204AL) is the industry-standard package designation and represents the modern equivalent to the A-405 package. Physical dimensions and lead spacing are compatible for PCB mounting.

Q: Why does the HER104G-AP show lower reverse leakage current than the HER104S-AP?

A: The HER104G-AP exhibits 5 µA reverse leakage at 300 V compared to 5 mA for the HER104S-AP. This difference reflects manufacturing process improvements and tighter quality control in the active product line. Lower reverse leakage is beneficial for circuit performance and does not create compatibility issues.

Q: Are there any compliance or regulatory differences between these parts?

A: Both parts are ROHS3 compliant. The HER104G-AP additionally carries REACH Unaffected status, confirming compliance with current European chemical regulations. No regulatory barriers exist to substitution.

Q: What is the inventory status of these parts?

A: The HER104S-AP is obsolete with 724 pieces available as new original stock. The HER104G-AP is an active product with 1155 pieces in inventory. For new designs and ongoing production, the HER104G-AP is the recommended choice based on product status and availability.

Q: Can the HER104G-AP be used in high-frequency switching applications?

A: Both parts feature fast recovery characteristics with 50 ns reverse recovery time, suitable for standard rectification applications. Specific high-frequency performance requirements should be evaluated against the application circuit specifications.

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