SK34 Schottky Diode 40V 3A SMC Equivalent & Substitute Parts

Part Overview

The SK34 is a Schottky rectifier diode rated for 40V DC reverse voltage and 3A average rectified current in a Surface Mount SMC (DO-214AB) package. This component is classified as obsolete, though 26,680 units remain in stock as new original inventory. The obsolete status necessitates identification of active equivalent and substitute parts to ensure design continuity and long-term supply chain reliability for applications requiring 40V/3A Schottky rectification performance.

Key Parameters

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

Substitute Part Grouping Explanation

Substitution of the SK34 is determined by strict equivalence across the following electrical and mechanical parameters:

Primary Equivalence Criteria (Direct Substitutes):

Voltage - DC Reverse (Vr) Maximum: 40V
Current - Average Rectified (Io): 3A
Voltage - Forward (Vf) Maximum @ If: 500 mV @ 3 A
Speed: Fast Recovery ≤ 500ns, > 200mA (Io)
Current - Reverse Leakage @ Vr: 500 µA @ 40 V
Package / Case: DO-214AB, SMC
Mounting Type: Surface Mount
Technology: Schottky

Secondary Consideration (Similar Parts): Parts that maintain the same voltage and current ratings but differ in package type (SMA, SMB) or current rating (5A) are classified as similar alternatives suitable only when package or current requirements permit substitution.

Direct substitutes must match all primary criteria. Similar parts are listed for reference when design flexibility allows package or current rating changes.

Parameter Comparison

Part Number	Manufacturer	Vr (Max) V	Io (A)	Vf (Max) @ If (mV @ A)	Reverse Leakage @ Vr (µA @ V)	Package	Tj (°C)	Product Status	RoHS Status
SK34	Micro Commercial Co	40	3	500 @ 3	500 @ 40	DO-214AB, SMC	-55 ~ 150	Obsolete	RoHS non-compliant
SK34-TP	Micro Commercial Co	40	3	500 @ 3	500 @ 40	DO-214AB, SMC	-55 ~ 150	Active	ROHS3 Compliant
B340-13-F	Diodes Incorporated	40	3	500 @ 3	500 @ 40	DO-214AB, SMC	-55 ~ 125	Active	ROHS3 Compliant
SS34-E3/57T	Vishay General Semiconductor - Diodes Division	40	3	500 @ 3	500 @ 40	DO-214AB, SMC	-55 ~ 125	Active	ROHS3 Compliant
SS34-E3/9AT	Vishay General Semiconductor - Diodes Division	40	3	500 @ 3	500 @ 40	DO-214AB, SMC	-55 ~ 125	Active	ROHS3 Compliant
CDBC340-G	Comchip Technology	40	3	500 @ 3	500 @ 40	DO-214AB, SMC	-55 ~ 125	Active	ROHS3 Compliant
CMSH3-40 BK PBFREE	Central Semiconductor Corp	40	3	500 @ 3	500 @ 40	DO-214AB, SMC	-65 ~ 150	Active	ROHS3 Compliant

Engineering Selection Recommendations

Direct Substitutes (Electrical and Mechanical Equivalence):

The following parts are direct substitutes for SK34 and maintain full electrical and mechanical compatibility:

SK34-TP (Micro Commercial Co) — Active status, ROHS3 compliant, identical electrical specifications, Tape & Reel packaging. Recommended as primary replacement from original manufacturer.
B340-13-F (Diodes Incorporated) — Active status, ROHS3 compliant, identical electrical specifications, Cut Tape & Digi-Reel packaging. Operating temperature range -55°C ~ 125°C (5°C lower maximum than SK34).
SS34-E3/57T (Vishay General Semiconductor - Diodes Division) — Active status, ROHS3 compliant, identical electrical specifications, Cut Tape packaging. Operating temperature range -55°C ~ 125°C.
SS34-E3/9AT (Vishay General Semiconductor - Diodes Division) — Active status, ROHS3 compliant, identical electrical specifications, Tape & Reel packaging. Operating temperature range -55°C ~ 125°C.
CDBC340-G (Comchip Technology) — Active status, ROHS3 compliant, identical electrical specifications, Tape & Reel packaging. Operating temperature range -55°C ~ 125°C.
CMSH3-40 BK PBFREE (Central Semiconductor Corp) — Active status, ROHS3 compliant, identical electrical specifications, extended operating temperature range -65°C ~ 150°C (matches SK34 upper limit). Bulk packaging.

Compliance Consideration:

SK34 is RoHS non-compliant. All direct substitutes listed above are ROHS3 compliant, meeting current regulatory requirements for new designs and manufacturing.

Temperature Derating:

Applications requiring the full -55°C ~ 150°C operating range of SK34 should select SK34-TP or CMSH3-40 BK PBFREE. Other direct substitutes operate to -55°C ~ 125°C maximum junction temperature.

Frequently Asked Questions (FAQ)

Q1: Can I use B340-13-F as a direct replacement for SK34?

A: Yes. B340-13-F meets all electrical specifications (40V, 3A, 500mV forward voltage, 500µA reverse leakage) and uses the same DO-214AB SMC package. The operating temperature range is -55°C ~ 125°C, which is 25°C lower than SK34's maximum. Verify your application does not require operation above 125°C junction temperature.

Q2: What is the difference between SK34-TP and SK34?

A: SK34-TP is the active production variant of SK34. Both share identical electrical specifications and package type (DO-214AB SMC). SK34-TP is ROHS3 compliant, whereas SK34 is RoHS non-compliant. SK34-TP is supplied in Tape & Reel format.

Q3: Are Vishay SS34-E3/57T and SS34-E3/9AT interchangeable?

A: Yes. Both parts are electrically identical (40V, 3A, 500mV forward voltage, 500µA reverse leakage) and use the same DO-214AB SMC package. The difference is packaging format: SS34-E3/57T is Cut Tape; SS34-E3/9AT is Tape & Reel. Select based on your assembly process requirements.

Q4: Why does CMSH3-40 BK PBFREE have a different reverse leakage specification?

A: CMSH3-40 BK PBFREE is listed as a direct substitute because it meets the primary electrical criteria (40V, 3A, 500mV forward voltage, 500µA reverse leakage @ 40V) and uses the same DO-214AB SMC package. Verify reverse leakage performance against your circuit requirements.

Q5: Can I substitute SK34 with B340LA-13-F or B340LB-13-F?

A: No. B340LA-13-F uses SMA package (DO-214AC), and B340LB-13-F uses SMB package (DO-214AA). These are different from SK34's SMC package (DO-214AB) and are not mechanically compatible with existing PCB layouts designed for SMC components.

Q6: What does "Fast Recovery ≤ 500ns, > 200mA (Io)" mean?

A: This specifies the diode's switching speed classification. Recovery time is 500 nanoseconds or less when switching currents greater than 200mA. This parameter is consistent across SK34 and all listed direct substitutes, ensuring equivalent switching performance in rectification circuits.

Q7: Is ROHS3 compliance required for my application?

A: ROHS3 compliance is mandatory for products sold in the European Union and many other markets. SK34 is RoHS non-compliant. All listed direct substitutes are ROHS3 compliant. If your design or supply chain requires RoHS compliance, select from the active substitute parts.

Q8: Which substitute offers the widest operating temperature range?

A: CMSH3-40 BK PBFREE and SK34-TP both support -55°C ~ 150°C junction temperature range, matching SK34's specification. Other direct substitutes operate to -55°C ~ 125°C maximum.

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