SK35 Schottky Rectifier Diode Equivalent & Substitute Parts

Part Overview

The SK35 is a Schottky rectifier diode manufactured by Micro Commercial Co, rated for 50 V DC reverse voltage and 3 A average rectified current in a Surface Mount SMC (DO-214AB) package. This component is classified as obsolete, making identification of equivalent and substitute parts essential for ongoing design support and production continuity. The SK35 operates across a junction temperature range of -55°C to 150°C and exhibits fast recovery characteristics suitable for high-frequency rectification applications.

Key Parameters

Parameter	Value	Unit
Voltage - DC Reverse (Vr) (Max)	50	V
Current - Average Rectified (Io)	3	A
Voltage - Forward (Vf) (Max) @ If	750 mV @ 3 A	mV
Speed	Fast Recovery ≤ 500ns, > 200mA (Io)	ns
Current - Reverse Leakage @ Vr	500	µA @ 50 V
Package / Case	DO-214AB, SMC	—
Operating Temperature - Junction	-55 to 150	°C
Technology	Schottky	—
Mounting Type	Surface Mount	—
RoHS Status	RoHS non-compliant	—

Substitute Part Grouping Explanation

Substitution of the SK35 is determined by strict adherence to the following electrical and mechanical parameters:

Primary Substitution Criteria:

Voltage - DC Reverse (Vr) (Max): Must equal or exceed 50 V
Current - Average Rectified (Io): Must equal or exceed 3 A
Technology: Schottky rectifier diode
Mounting Type: Surface Mount
Package / Case: DO-214AB, SMC (or compatible surface mount package)
Speed: Fast Recovery ≤ 500ns, > 200mA (Io)
Operating Temperature - Junction: Must support -55°C to 150°C minimum

Direct Equivalents are parts that match all primary criteria with identical voltage and current ratings in the same SMC package.

Compatible Substitutes are parts that meet or exceed the primary electrical specifications but may differ in package type (SMA, SMB) or have enhanced ratings (higher current capacity).

Similar Parts are components with reduced voltage ratings (40 V) or increased current ratings (5 A) that may be suitable depending on circuit design margins and application requirements.

Parameter Comparison

Part Number	Manufacturer	Vr (Max)	Io	Vf @ If	Package	Temp Range	Product Status	RoHS
SK35	Micro Commercial Co	50 V	3 A	750 mV @ 3 A	DO-214AB, SMC	-55 to 150°C	Obsolete	Non-compliant
B350A-13-F	Diodes Incorporated	50 V	3 A	700 mV @ 3 A	DO-214AC, SMA	-55 to 150°C	Active	ROHS3 Compliant
B350B-13-F	Diodes Incorporated	50 V	3 A	700 mV @ 3 A	DO-214AA, SMB	-55 to 150°C	Active	ROHS3 Compliant
B340Q-13-F	Diodes Incorporated	40 V	3 A	500 mV @ 3 A	DO-214AB, SMC	-55 to 150°C	Active	ROHS3 Compliant
B350-13-F	Diodes Incorporated	50 V	3 A	700 mV @ 3 A	DO-214AB, SMC	-55 to 125°C	Active	ROHS3 Compliant
B350Q-13-F	Diodes Incorporated	50 V	3 A	700 mV @ 3 A	DO-214AB, SMC	-55 to 150°C	Active	ROHS3 Compliant
B550C-13-F	Diodes Incorporated	50 V	5 A	700 mV @ 5 A	DO-214AB, SMC	-55 to 150°C	Active	ROHS3 Compliant
B550CQ-13-F	Diodes Incorporated	50 V	5 A	700 mV @ 5 A	DO-214AB, SMC	-55 to 150°C	Active	ROHS3 Compliant
HSM550J/TR13	Microchip Technology	50 V	5 A	650 mV @ 5 A	DO-214AB, SMC	-55 to 175°C	Active	Non-compliant
STPS340S	STMicroelectronics	40 V	3 A	630 mV @ 3 A	DO-214AB, SMC	-55 to 150°C	Active	ROHS3 Compliant
SK35_R1_00001	Panjit International Inc.	50 V	3 A	750 mV @ 3 A	DO-214AB, SMC	-55 to 150°C	Active	ROHS3 Compliant

Engineering Selection Recommendations

Recommended Direct Replacement:

SK35_R1_00001 (Panjit International Inc.) is the parametric equivalent with identical electrical specifications (50 V, 3 A, 750 mV forward voltage) in the same DO-214AB SMC package. This part is currently in active production status with 5600 units in stock and carries ROHS3 compliance, addressing the RoHS non-compliance limitation of the obsolete SK35.

Primary Active Substitutes (Same Voltage and Current Rating):

B350Q-13-F (Diodes Incorporated) provides an exact match in electrical performance (50 V, 3 A) within the DO-214AB SMC package with AEC-Q101 automotive qualification. This part is ROHS3 compliant and supports the full -55°C to 150°C temperature range.

B350-13-F (Diodes Incorporated) offers equivalent electrical specifications (50 V, 3 A) in the same SMC package with ROHS3 compliance. Note that the maximum junction temperature is limited to 125°C, which is acceptable for applications not requiring the full 150°C upper limit.

Alternative Package Options (Same Electrical Rating):

B350A-13-F (Diodes Incorporated) delivers 50 V, 3 A performance in a DO-214AC SMA package with AEC-Q101 qualification and ROHS3 compliance. This option is suitable when SMA package footprints are acceptable.

B350B-13-F (Diodes Incorporated) provides 50 V, 3 A performance in a DO-214AA SMB package with ROHS3 compliance. This option accommodates designs using SMB package specifications.

Higher Current Capacity Alternatives (Same Voltage):

B550C-13-F and B550CQ-13-F (Diodes Incorporated) both deliver 50 V at 5 A in the DO-214AB SMC package, providing increased current margin. These parts are ROHS3 compliant and support the full temperature range. B550CQ-13-F includes AEC-Q101 automotive qualification.

HSM550J/TR13 (Microchip Technology) offers 50 V at 5 A in DO-214AB SMC package with extended temperature range (-55°C to 175°C). This part is RoHS non-compliant but provides superior thermal performance.

Reduced Voltage Alternatives (Same Current Rating):

B340Q-13-F and STPS340S (40 V, 3 A) are suitable only for applications where the 40 V reverse voltage rating meets circuit requirements. Both are ROHS3 compliant in SMC packages. These parts are not recommended as direct replacements for 50 V rated designs.

Frequently Asked Questions (FAQ)

Q: Can B350Q-13-F directly replace SK35 in existing designs?

A: Yes. B350Q-13-F matches the SK35 across all critical parameters: 50 V reverse voltage, 3 A average rectified current, fast recovery speed, DO-214AB SMC package, and -55°C to 150°C operating range. The part is ROHS3 compliant and carries AEC-Q101 automotive qualification.

Q: What is the difference between B350-13-F and B350Q-13-F?

A: Both parts share identical electrical specifications (50 V, 3 A) and SMC packaging. The primary difference is that B350Q-13-F includes AEC-Q101 automotive qualification and supports the full -55°C to 150°C temperature range, while B350-13-F is limited to -55°C to 125°C maximum junction temperature.

Q: Can I use B350A-13-F or B350B-13-F as replacements?

A: B350A-13-F and B350B-13-F are electrically equivalent (50 V, 3 A) but use different surface mount packages (SMA and SMB respectively, versus SMC). These parts are suitable only if the PCB layout and assembly process accommodate the alternative package footprints.

Q: Why would I choose a 5 A part like B550C-13-F over the 3 A SK35?

A: The B550C-13-F and B550CQ-13-F provide identical 50 V reverse voltage with increased current capacity (5 A versus 3 A). These parts are appropriate for designs requiring additional current margin or where thermal performance benefits from lower forward voltage drop at higher currents.

Q: Is SK35_R1_00001 a true equivalent to SK35?

A: Yes. SK35_R1_00001 is a parametric equivalent manufactured by Panjit International Inc. with identical specifications: 50 V, 3 A, 750 mV forward voltage, DO-214AB SMC package, and -55°C to 150°C operating range. This part is currently in active production with ROHS3 compliance.

Q: Can I use 40 V rated parts like B340Q-13-F or STPS340S?

A: 40 V rated parts are not recommended as direct replacements for the 50 V SK35 unless circuit analysis confirms that the application operates at voltages below 40 V. Using a lower voltage rating diode in a 50 V circuit creates risk of reverse voltage breakdown.

Q: What is the significance of RoHS compliance in selecting a substitute?

A: The SK35 is RoHS non-compliant. Most active substitutes (B350Q-13-F, B350-13-F, B350A-13-F, B350B-13-F, B550C-13-F, B550CQ-13-F, STPS340S, SK35_R1_00001) are ROHS3 compliant, meeting environmental and regulatory requirements for new designs and production. HSM550J/TR13 is RoHS non-compliant and should be selected only when legacy compliance status is acceptable.

Q: How do forward voltage differences affect circuit performance?

A: The SK35 specifies 750 mV forward voltage at 3 A. Most Diodes Incorporated substitutes specify 700 mV at 3 A, representing a 50 mV reduction. This lower forward voltage results in reduced power dissipation and improved efficiency. STPS340S specifies 630 mV at 3 A (40 V rating), and HSM550J/TR13 specifies 650 mV at 5 A. Forward voltage differences of this magnitude are typically acceptable in rectifier applications but should be verified against circuit design margins.

Q: What does AEC-Q101 qualification mean?

A: AEC-Q101 is an automotive electronics qualification standard. Parts carrying this qualification (B350A-13-F, B350Q-13-F, B550CQ-13-F) have undergone rigorous testing for reliability and performance in automotive environments. This certification is relevant for automotive and high-reliability applications.

Q: Can I mix different substitute parts in the same design?

A: All recommended substitutes are electrically and mechanically compatible within their specified package types. However, for production consistency and supply chain management, selecting a single qualified part number is preferred. If multiple part numbers are used, ensure that PCB layout and assembly processes accommodate any package differences.

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