SS34 Schottky Diode Equivalent & Substitute Parts

Part Overview

The SS34 is a 40V, 3A Schottky rectifier diode in SMC (DO-214AB) surface mount package manufactured by onsemi. This component is classified as "Not For New Designs," indicating it has reached end-of-life status. The part remains in inventory with 605,100 units available. Equivalent and substitute parts are necessary to support existing designs, provide alternative sourcing options, and enable transition to active product lines with comparable electrical and mechanical characteristics.

Key Parameters

Parameter	Value
Voltage - DC Reverse (Vr) (Max)	40 V
Current - Average Rectified (Io)	3 A
Voltage - Forward (Vf) (Max) @ If	500 mV @ 3 A
Speed	Fast Recovery ≤ 500ns, > 200mA (Io)
Current - Reverse Leakage @ Vr	500 µA @ 40 V
Package / Case	DO-214AB, SMC
Operating Temperature - Junction	-55°C ~ 150°C
Technology	Schottky
Mounting Type	Surface Mount
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution of the SS34 is determined by strict electrical and mechanical parameter matching. The following criteria establish valid equivalency:

Primary Substitution Criteria:

Voltage - DC Reverse (Vr) (Max): 40 V minimum
Current - Average Rectified (Io): 3 A minimum
Voltage - Forward (Vf) (Max) @ If: 500 mV or lower @ 3 A
Technology: Schottky
Package / Case: DO-214AB, SMC (primary); DO-214AA, SMB (secondary with package change)
Operating Temperature - Junction: -55°C minimum to 150°C maximum
Speed: Fast Recovery ≤ 500ns, > 200mA (Io)

Grouping Categories:

Group 1: Direct Electrical & Package Equivalents (DO-214AB, SMC) Parts meeting all primary criteria with identical package and thermal specifications. These provide pin-for-pin and footprint-compatible replacement.

Group 2: Electrical Equivalents with Higher Current Rating (DO-214AB, SMC) Parts exceeding the 3A current requirement while maintaining 40V reverse voltage and compatible package. These provide enhanced current capability within the same footprint.

Group 3: Electrical Equivalents with Package Variation (DO-214AA, SMB) Parts meeting electrical criteria but using alternative surface mount package. These require PCB layout modification.

Group 4: Lower Current Density Alternatives Parts with reduced current ratings that do not meet minimum 3A specification. These are not suitable for direct substitution.

Parameter Comparison

Part Number	Manufacturer	Vr (Max)	Io	Vf (Max) @ If	Package	Temp Range	Product Status	Reverse Leakage @ Vr
SS34	onsemi	40 V	3 A	500 mV @ 3 A	DO-214AB, SMC	-55°C ~ 150°C	Not For New Designs	500 µA @ 40 V
MBRS340T3G	onsemi	40 V	3 A	500 mV @ 3 A	DO-214AB, SMC	-65°C ~ 150°C	Active	2 mA @ 40 V
SK34-TP	Micro Commercial Co	40 V	3 A	500 mV @ 3 A	DO-214AB, SMC	-55°C ~ 150°C	Active	500 µA @ 40 V
SK34-TP-HF	Micro Commercial Co	40 V	3 A	500 mV @ 3 A	DO-214AB, SMC	-55°C ~ 150°C	Active	500 µA @ 40 V
B340-13-F	Diodes Incorporated	40 V	3 A	500 mV @ 3 A	DO-214AB, SMC	-55°C ~ 125°C	Active	500 µA @ 40 V
B540C-13-F	Diodes Incorporated	40 V	5 A	550 mV @ 5 A	DO-214AB, SMC	-55°C ~ 150°C	Active	500 µA @ 40 V
B540CQ-13-F	Diodes Incorporated	40 V	5 A	550 mV @ 5 A	DO-214AB, SMC	-55°C ~ 150°C	Active	500 µA @ 40 V
CDBC340-G	Comchip Technology	40 V	3 A	500 mV @ 3 A	DO-214AB, SMC	-55°C ~ 125°C	Active	500 µA @ 40 V
SK34B-TP	Micro Commercial Co	40 V	3 A	500 mV @ 3 A	DO-214AA, SMB	-55°C ~ 125°C	Obsolete	500 µA @ 40 V

Engineering Selection Recommendations

Group 1: Direct Equivalents (Recommended for Replacement)

MBRS340T3G (onsemi), SK34-TP (Micro Commercial Co), SK34-TP-HF (Micro Commercial Co), B340-13-F (Diodes Incorporated), and CDBC340-G (Comchip Technology) are direct electrical and mechanical equivalents to the SS34. All parts maintain 40V reverse voltage, 3A average rectified current, 500mV forward voltage drop, and DO-214AB SMC package compatibility.

MBRS340T3G is an active product from onsemi, the original SS34 manufacturer, with extended temperature range (-65°C to 150°C) and represents the direct successor. This part is preferred for new production and replacement applications.

SK34-TP and SK34-TP-HF from Micro Commercial Co are active products with identical electrical specifications and package footprint. Both support the full -55°C to 150°C operating range.

B340-13-F from Diodes Incorporated is an active product with identical electrical specifications. Operating temperature range is -55°C to 125°C, which is acceptable for most applications but does not extend to the full 150°C maximum of the SS34.

CDBC340-G from Comchip Technology is an active product with identical electrical specifications. Operating temperature maximum is 125°C, similar to B340-13-F.

All Group 1 parts are RoHS3 compliant and REACH unaffected, matching the SS34 compliance profile.

Group 2: Higher Current Alternatives (Conditional Substitution)

B540C-13-F and B540CQ-13-F from Diodes Incorporated provide 5A average rectified current at 40V reverse voltage. These parts are suitable for applications where the SS34's 3A rating is marginal or where design margin is required. Both maintain DO-214AB SMC package compatibility and -55°C to 150°C operating range. B540CQ-13-F includes AEC-Q101 automotive qualification.

Forward voltage drop increases to 550mV @ 5A, which may affect circuit performance in low-voltage applications. These parts are appropriate only when the higher current capability provides design benefit.

Group 3: Package Variant (Not Recommended)

SK34B-TP uses DO-214AA (SMB) package instead of DO-214AB (SMC). This part is marked as Obsolete and requires PCB layout modification. This option is not recommended for new designs or standard replacement applications.

Group 4: Lower Current Alternatives (Not Suitable)

BAT165E6327HTSA1 from Infineon Technologies provides only 750mA average rectified current, which does not meet the SS34's 3A minimum requirement. This part is not suitable for direct substitution.

Compliance and Certification:

All recommended Group 1 and Group 2 parts maintain RoHS3 compliance and REACH unaffected status, consistent with the SS34. No additional qualification or compliance verification is required for these substitutions.

Frequently Asked Questions (FAQ)

Q: Can MBRS340T3G directly replace SS34 in existing designs?

A: Yes. MBRS340T3G is electrically and mechanically equivalent to SS34. Both parts share identical 40V reverse voltage, 3A current rating, 500mV forward voltage drop, and DO-214AB SMC package. MBRS340T3G is an active product from onsemi, the SS34 manufacturer, and is the recommended replacement for end-of-life SS34 applications.

Q: What is the difference between SK34-TP and SK34-TP-HF?

A: Both parts are manufactured by Micro Commercial Co and provide identical electrical specifications: 40V reverse voltage, 3A current, 500mV forward voltage drop, and DO-214AB SMC package. The "-HF" designation indicates a high-frequency variant, though both parts meet the same fast recovery specification (≤500ns, >200mA). Selection between these parts depends on supplier availability and specific application requirements.

Q: Can B540C-13-F be used instead of SS34?

A: B540C-13-F is electrically compatible but provides higher current capability (5A vs. 3A). The part maintains 40V reverse voltage and DO-214AB SMC package compatibility. Forward voltage increases to 550mV @ 5A. This substitution is acceptable when the higher current rating provides design margin or when the application requires enhanced current handling. Verify that the increased forward voltage drop does not affect circuit performance.

Q: Why is B340-13-F's operating temperature range limited to 125°C?

A: B340-13-F from Diodes Incorporated specifies a maximum junction temperature of 125°C, compared to SS34's 150°C. This difference reflects the manufacturer's thermal design and qualification limits. For applications operating near or above 125°C, MBRS340T3G or SK34-TP are preferred alternatives that support the full -55°C to 150°C range.

Q: Is SK34B-TP a suitable replacement for SS34?

A: SK34B-TP is not recommended. Although electrically equivalent, this part uses DO-214AA (SMB) package instead of SS34's DO-214AB (SMC) package. This package difference requires PCB layout modification and is marked as Obsolete. Use SK34-TP or SK34-TP-HF instead, which maintain the DO-214AB SMC package.

Q: What does "Not For New Designs" mean for the SS34?

A: "Not For New Designs" indicates that SS34 has reached end-of-life status and is no longer recommended for new product development. Existing inventory remains available for support of legacy designs. For new applications, select from active products such as MBRS340T3G, SK34-TP, B340-13-F, or CDBC340-G.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All recommended substitute parts (MBRS340T3G, SK34-TP, SK34-TP-HF, B340-13-F, B540C-13-F, B540CQ-13-F, and CDBC340-G) are RoHS3 compliant and REACH unaffected, matching the SS34 compliance profile.

Q: What is the significance of reverse leakage current differences between parts?

A: Reverse leakage current is specified at maximum reverse voltage (40V). SS34 specifies 500µA @ 40V. MBRS340T3G specifies 2mA @ 40V, which is higher but remains within acceptable limits for most rectifier applications. Other substitutes maintain 500µA @ 40V. For applications sensitive to leakage current, verify that the specified leakage does not exceed circuit requirements.

Q: Can BAT165E6327HTSA1 replace SS34?

A: No. BAT165E6327HTSA1 provides only 750mA average rectified current, which does not meet SS34's 3A minimum requirement. This part is not suitable for direct substitution. Use only parts rated for 3A or higher current.

Q: What packaging options are available for SS34 substitutes?

A: All recommended substitutes use DO-214AB (SMC) surface mount package, providing identical footprint and pin compatibility with SS34. This package is standard for 3A Schottky rectifiers in this voltage class. SK34B-TP uses alternative DO-214AA (SMB) package and is not recommended due to obsolete status and required layout modification.

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