CDBB540-HF Schottky Diode Equivalent & Substitute Parts

Part Overview

The CDBB540-HF is an active Schottky rectifier diode manufactured by Comchip Technology, rated for 40V DC reverse voltage and 5A average rectified current in a surface mount DO-214AA (SMB) package. This component is designed for fast recovery applications requiring low forward voltage drop and rapid switching characteristics. Equivalent and substitute parts are identified when circuit designs require alternative sourcing, inventory management, or when original manufacturer components become unavailable while maintaining functional compatibility within specified electrical and mechanical parameters.

Key Parameters

Parameter	Value	Unit
Voltage - DC Reverse (Vr) (Max)	40	V
Current - Average Rectified (Io)	5	A
Voltage - Forward (Vf) (Max) @ If	550 mV @ 5 A	mV
Speed	Fast Recovery ≤ 500ns, > 200mA (Io)	ns
Current - Reverse Leakage @ Vr	500	µA @ 40 V
Capacitance @ Vr, F	300	pF @ 4V, 1MHz
Package / Case	DO-214AA, SMB	—
Operating Temperature - Junction	-50 to 125	°C
Technology	Schottky	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitute parts for the CDBB540-HF are identified based on the following critical electrical and mechanical parameters:

Mandatory Matching Criteria:

Voltage - DC Reverse (Vr) (Max): 40V minimum
Package / Case: DO-214AA or SMB equivalent
Technology: Schottky diode
Mounting Type: Surface Mount
RoHS Compliance: ROHS3 Compliant

Allowable Parameter Variations:

Current - Average Rectified (Io): Equal to or greater than 5A
Voltage - Forward (Vf) (Max): Equal to or less than 550 mV at rated current
Operating Temperature - Junction: Range must encompass -50°C to 125°C minimum
Current - Reverse Leakage @ Vr: Equal to or less than 500 µA @ 40V

The SK44BL-TP from Micro Commercial Co qualifies as a substitute part. While its rated current is 4A (lower than the 5A specification of CDBB540-HF), it meets all other mandatory criteria and operates within compatible electrical parameters for applications where the 4A rating is acceptable.

Parameter Comparison

Parameter	CDBB540-HF (Comchip)	SK44BL-TP (Micro Commercial Co)	Compatibility Notes
Voltage - DC Reverse (Vr) (Max)	40 V	40 V	Identical
Current - Average Rectified (Io)	5 A	4 A	SK44BL-TP rated lower; verify application current requirements
Voltage - Forward (Vf) (Max) @ If	550 mV @ 5 A	450 mV @ 4 A	SK44BL-TP exhibits lower forward voltage
Speed	Fast Recovery ≤ 500ns, > 200mA (Io)	Fast Recovery ≤ 500ns, > 200mA (Io)	Identical
Current - Reverse Leakage @ Vr	500 µA @ 40 V	500 µA @ 40 V	Identical
Package / Case	DO-214AA, SMB	DO-214AA, HSMB	Both surface mount SMB variants; footprint compatible
Operating Temperature - Junction	-50 to 125 °C	-55 to 150 °C	SK44BL-TP has wider operating range
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	Identical
Moisture Sensitivity Level (MSL)	1 (Unlimited)	1 (Unlimited)	Identical

Engineering Selection Recommendations

CDBB540-HF Selection: Select the CDBB540-HF when the application requires the full 5A average rectified current rating and forward voltage characteristics at 5A operation. This part is active in production with ROHS3 compliance and unlimited moisture sensitivity rating, suitable for standard industrial and commercial applications.

SK44BL-TP Selection: The SK44BL-TP from Micro Commercial Co is suitable as a substitute when circuit design permits operation at 4A average rectified current or lower. This part offers improved forward voltage performance (450 mV @ 4A versus 550 mV @ 5A) and an extended operating temperature range (-55 to 150°C). Both parts maintain identical reverse voltage ratings, fast recovery characteristics, and RoHS3 compliance. The SK44BL-TP is currently in higher inventory availability (4200 pcs versus 882 pcs for CDBB540-HF).

Compliance Basis: Both parts are ROHS3 compliant, REACH unaffected, and classified under ECCN EAR99 with identical HTSUS codes (8541.10.0080), confirming regulatory equivalence for procurement and export purposes.

Frequently Asked Questions (FAQ)

Q: Can SK44BL-TP directly replace CDBB540-HF in all applications?

A: Direct replacement is valid only when the application current requirement does not exceed 4A. The SK44BL-TP is rated for 4A average rectified current, which is lower than the CDBB540-HF 5A rating. Circuit analysis must confirm that peak and average currents remain within the 4A limit.

Q: What is the difference between DO-214AA and HSMB packaging?

A: Both designations refer to surface mount SMB (Small Outline Molded Bipolar) packages. DO-214AA is the JEDEC standard designation, while HSMB is a supplier-specific variant designation. The physical footprint and lead spacing are compatible for PCB assembly.

Q: Why does SK44BL-TP have lower forward voltage than CDBB540-HF?

A: Forward voltage is measured at the part's rated current. SK44BL-TP is specified at 4A (450 mV), while CDBB540-HF is specified at 5A (550 mV). The lower forward voltage at lower current is a characteristic of Schottky diode behavior and does not indicate superior performance; it reflects measurement at different operating points.

Q: Are there any temperature-related limitations when substituting?

A: The SK44BL-TP operates from -55 to 150°C, which exceeds the CDBB540-HF range of -50 to 125°C. For applications within the CDBB540-HF temperature range, both parts are compatible. For applications requiring operation below -50°C or above 125°C, only SK44BL-TP is suitable.

Q: Do both parts have identical reverse leakage characteristics?

A: Yes. Both CDBB540-HF and SK44BL-TP specify 500 µA reverse leakage current at 40V, ensuring equivalent performance in reverse bias conditions.

Q: What is the significance of MSL Level 1 (Unlimited)?

A: MSL Level 1 (Unlimited) indicates that both parts have unlimited shelf life and do not require special moisture control during storage or handling. No baking or desiccant storage is required prior to assembly.

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