CDBK0540 Schottky Diode 40V 500mA SOD-123F Equivalent & Substitute Parts

Part Overview

The CDBK0540 is a Schottky rectifier diode manufactured by Comchip Technology, rated for 40V DC reverse voltage with 500mA average rectified current in a surface mount SOD-123F package. This component is classified as obsolete, making identification of compatible substitute parts essential for ongoing design support and procurement continuity. The fast recovery characteristics (≤500ns for currents >200mA) and low forward voltage drop typical of Schottky technology make this diode suitable for high-frequency rectification and power conversion applications.

Substiute Parts

CDBK0540

Comchip TechnologyIn Stock: 800CDBK0540 Datasheet

Current PartRFQ

RBR1MM40ATR

Rohm SemiconductorIn Stock: 1792RBR1MM40ATR Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the CDBK0540 is determined by strict equivalence across the following critical electrical and mechanical parameters:

Mandatory Matching Criteria:

• Voltage - DC Reverse (Vr) (Max): 40V minimum
• Package / Case: SOD-123F surface mount form factor
• Technology: Schottky rectifier diode
• Mounting Type: Surface Mount

Allowable Parameter Variations:

• Current - Average Rectified (Io): Equal to or greater than 500mA
• Voltage - Forward (Vf) (Max): Within acceptable circuit tolerance (typically ±50mV for rectification applications)
• Reverse Recovery Time (trr): Equal to or less than specified value
• Operating Temperature - Junction (Max): Equal to or greater than 125°C
• Current - Reverse Leakage @ Vr: Equal to or less than specified value

The substitute part RBR1MM40ATR meets all mandatory criteria and exceeds minimum current rating (1A vs. 500mA), making it a direct functional replacement.

Parameter Comparison

Engineering Selection Recommendations

RBR1MM40ATR (Rohm Semiconductor) - Direct Substitute

The RBR1MM40ATR is a qualified substitute for the obsolete CDBK0540. Selection rationale:

• Voltage Rating: Identical 40V DC reverse voltage specification ensures compatibility with existing circuit design parameters.
• Current Capacity: 1A rating exceeds the 500mA requirement of the original part, providing design margin and thermal headroom.
• Package Compatibility: Both parts use SOD-123F surface mount packaging, enabling direct PCB footprint compatibility without layout modification.
• Product Status: Active manufacturing status by Rohm Semiconductor ensures long-term availability and supply chain continuity, addressing the obsolescence of the original CDBK0540.
• Compliance: RoHS3 compliant and REACH unaffected status meets current regulatory requirements for electronic component procurement.
• Operating Temperature: 150°C maximum junction temperature exceeds the 125°C specification of the original part, supporting higher thermal stress applications.

The RBR1MM40ATR is suitable for direct replacement in new designs and legacy system support where the CDBK0540 is no longer available.

Frequently Asked Questions (FAQ)

Q: Can the RBR1MM40ATR be used as a direct drop-in replacement for the CDBK0540?

A: Yes. Both parts share identical voltage rating (40V), package form factor (SOD-123F), and fast recovery Schottky technology. The substitute part meets or exceeds all critical electrical parameters of the original component.

Q: What is the significance of the higher current rating (1A vs. 500mA) on the RBR1MM40ATR?

A: The higher current rating provides design margin and thermal headroom. In applications where the original CDBK0540 was rated at 500mA, the RBR1MM40ATR operates at lower junction temperature stress, extending component life and improving reliability.

Q: Are there any PCB layout considerations when substituting the RBR1MM40ATR for the CDBK0540?

A: No layout changes are required. Both components use the SOD-123F surface mount package with identical pin configuration and footprint dimensions. Existing PCB designs require no modification.

Q: How do the forward voltage characteristics compare between these parts?

A: The CDBK0540 specifies 510mV maximum forward voltage at 500mA, while the RBR1MM40ATR specifies 520mV maximum at 1A. The 10mV difference is within typical circuit tolerance for rectification applications and does not impact functional performance in standard power conversion designs.

Q: What is the difference in reverse leakage current between these parts?

A: The CDBK0540 specifies 20µA maximum reverse leakage at 40V, while the RBR1MM40ATR specifies 50µA at the same voltage. This difference is acceptable for rectifier applications and does not significantly impact circuit performance in typical switching or rectification circuits.

Q: Why is the CDBK0540 classified as obsolete?

A: Obsolescence indicates that Comchip Technology has discontinued manufacturing this part. The RBR1MM40ATR from Rohm Semiconductor is an active product with confirmed ongoing production, ensuring availability for current and future procurement needs.

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

A: The RBR1MM40ATR carries RoHS3 compliance certification, meeting current environmental and hazardous substance restrictions. Both parts are REACH unaffected and carry EAR99 export classification. The substitute part meets or exceeds all regulatory requirements applicable to the original component.