KMB125S Equivalent & Substitute Parts

Part Overview

The KMB125S is a single-phase Schottky bridge rectifier diode manufactured by SMC Diode Solutions, rated for 1 A average rectified current and 250 V peak reverse voltage. The device is packaged in a 4-SMD, Gull Wing surface mount configuration (MBS package) and operates across a temperature range of -55°C to 150°C. The KMB125S is classified as obsolete, necessitating identification of equivalent substitute components for ongoing design support and procurement requirements.

Key Parameters

Parameter	Value
Diode Type	Single Phase
Technology	Schottky
Voltage - Peak Reverse (Max)	250 V
Current - Average Rectified (Io)	1 A
Voltage - Forward (Vf) (Max) @ If	920 mV @ 1 A
Current - Reverse Leakage @ Vr	50 µA @ 250 V
Operating Temperature Range	-55°C ~ 150°C (TJ)
Mounting Type	Surface Mount
Package / Case	4-SMD, Gull Wing
Supplier Device Package	MBS
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution of the KMB125S is determined by the following critical parameters:

Mandatory Matching Parameters:

Diode Type: Single Phase
Technology: Schottky
Current - Average Rectified (Io): 1 A
Mounting Type: Surface Mount
Package / Case: 4-SMD, Gull Wing
Supplier Device Package: MBS
Operating Temperature Range: -55°C ~ 150°C (TJ)

Allowable Variation Parameters:

Voltage - Peak Reverse (Max): Equal to or greater than 250 V
Voltage - Forward (Vf) (Max) @ If: Equal to or less than 920 mV @ 1 A
Current - Reverse Leakage @ Vr: Equal to or less than 50 µA at rated voltage

The KMB120S qualifies as a substitute component. While it operates at a reduced peak reverse voltage rating of 200 V (lower than the original 250 V specification), it maintains identical current ratings, package configuration, and thermal operating range. The forward voltage characteristic is improved at 900 mV versus 920 mV. This substitution is valid for applications where the circuit peak reverse voltage does not exceed 200 V.

Parameter Comparison

Parameter	KMB125S (Original)	KMB120S (Substitute)
Manufacturer	SMC Diode Solutions	SMC Diode Solutions
Diode Type	Single Phase	Single Phase
Technology	Schottky	Schottky
Voltage - Peak Reverse (Max)	250 V	200 V
Current - Average Rectified (Io)	1 A	1 A
Voltage - Forward (Vf) (Max) @ If	920 mV @ 1 A	900 mV @ 1 A
Current - Reverse Leakage @ Vr	50 µA @ 250 V	50 µA @ 200 V
Operating Temperature Range	-55°C ~ 150°C (TJ)	-55°C ~ 150°C (TJ)
Mounting Type	Surface Mount	Surface Mount
Package / Case	4-SMD, Gull Wing	4-SMD, Gull Wing
Supplier Device Package	MBS	MBS
Moisture Sensitivity Level (MSL)	1 (Unlimited)	1 (Unlimited)
Product Status	Obsolete	Active

Engineering Selection Recommendations

The KMB120S is the manufacturer-recommended substitute for the obsolete KMB125S. Selection of this substitute component is based on the following factors:

Product Status: The KMB120S maintains active product status with confirmed inventory availability (653 pieces), whereas the KMB125S is obsolete. Transition to the KMB120S ensures access to current manufacturing and supply chain support.

Compliance and Certifications: The KMB120S is RoHS3 compliant, providing enhanced environmental and regulatory alignment compared to the original part. Both components share identical REACH Affected status, ECCN classification (EAR99), and HTSUS code (8541.10.0080).

Electrical Compatibility: The KMB120S operates at 200 V peak reverse voltage, which is 50 V lower than the KMB125S specification. This substitution is valid only for circuits where the maximum reverse voltage does not exceed 200 V. The forward voltage characteristic is superior at 900 mV versus 920 mV, resulting in reduced power dissipation.

Physical and Thermal Compatibility: Both components share identical mounting type (surface mount), package configuration (4-SMD, Gull Wing), and operating temperature range (-55°C to 150°C). Direct footprint compatibility is confirmed.

Frequently Asked Questions (FAQ)

Q: Can the KMB120S be used as a direct replacement for the KMB125S in all applications?

A: The KMB120S is a direct physical and thermal replacement. However, electrical compatibility depends on circuit design. The substitute operates at 200 V peak reverse voltage versus the original 250 V. Substitution is valid only if the circuit peak reverse voltage specification does not exceed 200 V.

Q: What is the primary reason for substituting the KMB125S?

A: The KMB125S is classified as obsolete. The KMB120S is the manufacturer-recommended active substitute, ensuring continued availability and supply chain support.

Q: Are there any performance improvements with the KMB120S?

A: The KMB120S exhibits a lower forward voltage drop (900 mV versus 920 mV at 1 A), resulting in reduced power dissipation and improved thermal efficiency within the specified operating range.

Q: Is the KMB120S RoHS compliant?

A: Yes, the KMB120S is RoHS3 compliant. The original KMB125S does not specify RoHS compliance status.

Q: Are the package and mounting configurations identical?

A: Yes. Both the KMB125S and KMB120S use 4-SMD, Gull Wing surface mount packaging (MBS package). Footprint compatibility is confirmed, allowing direct PCB placement without modification.

Q: What is the moisture sensitivity level for the KMB120S?

A: Both components are rated MSL 1 (Unlimited), indicating no moisture sensitivity restrictions during storage or handling.

Q: How does the reverse leakage current compare between the two parts?

A: The KMB125S specifies 50 µA leakage at 250 V, while the KMB120S specifies 50 µA leakage at 200 V. Leakage current is measured at the respective rated voltages for each component.

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