T520B686M006ASE040 Equivalent & Substitute Parts

Part Overview

The T520B686M006ASE040 is a 68 µF molded tantalum polymer capacitor rated at 6.3 V with 40 mOhm equivalent series resistance at 100 kHz, manufactured by KEMET in the KO-CAP® T520 series. This component is classified as obsolete, necessitating identification of active equivalent alternatives for new designs and production continuity. Substitute parts must maintain identical electrical specifications and mechanical compatibility to ensure direct replacement without circuit redesign.

Substiute Parts

T520B686M006ASE040

KEMETIn Stock: 983T520B686M006ASE040 Datasheet

Current PartRFQ

T520B686M006ATE040

KEMETIn Stock: 34025T520B686M006ATE040 Datasheet

DirectRFQ

T55B686M6R3C0070

Vishay SpragueIn Stock: 2831T55B686M6R3C0070 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the T520B686M006ASE040 are qualified based on the following critical parameters:

Electrical Equivalence Criteria:

• Capacitance: 68 µF (exact match required)
• Voltage Rating: 6.3 V (exact match required)
• Tolerance: ±20% (exact match required)
• Operating Temperature Range: -55°C ~ 105°C (exact match required)
• Type: Molded tantalum polymer (exact match required)

Mechanical Compatibility Criteria:

• Package / Case: 1411 (3528 Metric) (exact match required)
• Size / Dimension: 0.138" L x 0.110" W (3.50mm x 2.80mm) (exact match required)
• Mounting Type: Surface Mount (exact match required)
• Moisture Sensitivity Level: 3 (168 Hours) (exact match required)

Acceptable Variation:

• ESR @ 100 kHz: Substitutes with higher ESR values are acceptable provided they do not exceed application-specific ripple current and thermal dissipation limits. The main part specifies 40 mOhm; substitutes may range up to 70 mOhm within the same package class.

Compliance Consideration:

• RoHS Status: Active substitutes must comply with ROHS3 standards, as the original part is RoHS non-compliant and obsolete.

Parameter Comparison

Engineering Selection Recommendations

Primary Substitute: T520B686M006ATE040 (KEMET)

The T520B686M006ATE040 is the direct equivalent of the obsolete T520B686M006ASE040. Both parts are from the same KEMET KO-CAP® T520 series and share identical electrical and mechanical specifications, including 68 µF capacitance, 6.3 V rating, 40 mOhm ESR, and 1411 package dimensions. The primary distinction is product status: T520B686M006ATE040 is active and ROHS3 compliant, whereas the original part is obsolete and RoHS non-compliant. The substitute is supplied in Tape & Reel packaging, suitable for automated assembly. This part is the recommended first choice for direct replacement.

Secondary Substitute: T55B686M6R3C0070 (Vishay Sprague)

The T55B686M6R3C0070 from Vishay Sprague's vPolyTan™ T55 series provides functional equivalence with the following considerations:

• Electrical parameters (capacitance, voltage, tolerance, temperature range) are identical to the main part.
• Mechanical compatibility is maintained: same 1411 (3528 Metric) package and footprint dimensions.
• ESR is 70 mOhm at 100 kHz, compared to 40 mOhm for the main part. This 75% increase in ESR is within acceptable limits for general-purpose applications but may affect ripple current handling and thermal performance in high-frequency or high-current environments.
• Seated height is 0.083" (2.10mm) versus 0.079" (2.00mm) for the main part, representing a 0.04mm increase. This marginal difference is acceptable for most PCB layouts but requires verification in space-constrained designs.
• Product status is active with ROHS3 compliance.

This part is suitable as a secondary alternative when the primary KEMET substitute is unavailable, provided application thermal and ripple current requirements accommodate the higher ESR specification.

Frequently Asked Questions (FAQ)

Q1: Can T520B686M006ATE040 be used as a direct replacement for T520B686M006ASE040?

A: Yes. Both parts are electrically and mechanically identical, with 68 µF capacitance, 6.3 V rating, 40 mOhm ESR, and 1411 package dimensions. The substitute is active and ROHS3 compliant, whereas the original is obsolete. No circuit modifications are required.

Q2: What is the difference between the KEMET and Vishay substitutes?

A: The KEMET T520B686M006ATE040 is a direct equivalent with identical ESR (40 mOhm) and seated height (0.079"). The Vishay T55B686M6R3C0070 has higher ESR (70 mOhm) and slightly greater seated height (0.083"). Both maintain electrical equivalence and mechanical compatibility. The KEMET part is the preferred choice; the Vishay part is a secondary alternative.

Q3: Does the higher ESR of the Vishay substitute affect circuit performance?

A: The Vishay substitute has 70 mOhm ESR compared to 40 mOhm for the main part. This 75% increase may impact ripple current handling and thermal dissipation in high-frequency or high-current applications. For general-purpose applications, the difference is typically acceptable. Application-specific analysis is required for critical designs.

Q4: Are there packaging differences between the substitutes?

A: The original part is supplied in bulk packaging. Both substitutes are supplied in Tape & Reel (TR) format, suitable for automated assembly. The electrical and mechanical specifications remain unchanged.

Q5: Is the 0.04mm height difference of the Vishay substitute significant?

A: The Vishay substitute has a seated height of 0.083" (2.10mm) versus 0.079" (2.00mm) for the main part. This marginal difference is acceptable for most PCB layouts. Verification is required only in space-constrained designs with tight height tolerances.

Q6: Are both substitutes RoHS compliant?

A: Yes. Both T520B686M006ATE040 (KEMET) and T55B686M6R3C0070 (Vishay Sprague) are ROHS3 compliant. The original T520B686M006ASE040 is RoHS non-compliant.

Q7: What is the moisture sensitivity level for these parts?

A: All three parts—the main part and both substitutes—have Moisture Sensitivity Level 3 (168 Hours). Identical handling and storage protocols apply.

Q8: Can these parts be used interchangeably in existing designs?

A: The KEMET T520B686M006ATE040 can be used interchangeably without any design changes. The Vishay T55B686M6R3C0070 is mechanically and electrically compatible but requires application review due to higher ESR and marginal height difference.