T520B686M004ASE040 Equivalent & Substitute Parts

Part Overview

The T520B686M004ASE040 is a 68 µF molded tantalum polymer capacitor rated for 4 V operation in a 1411 (3528 Metric) surface mount package. This component is classified as obsolete, indicating discontinuation by the manufacturer KEMET. Identification of equivalent and substitute parts is necessary to maintain design continuity and ensure procurement availability for applications requiring this capacitance and voltage rating.

Key Parameters

Parameter	Value
Capacitance	68 µF
Voltage Rating	4 V
Package / Case	1411 (3528 Metric)
Type	Molded Tantalum Polymer
Mounting Type	Surface Mount
ESR @ 100kHz	40 mOhm (main part)
Operating Temperature Range	-55°C to 105°C
Tolerance	±20%

Substitute Part Grouping Explanation

Substitution of the T520B686M004ASE040 is determined by strict equivalence in the following parameters:

Capacitance: 68 µF (exact match required)
Voltage Rating: 4 V (exact match required)
Package / Case: 1411 (3528 Metric) (exact match required)
Mounting Type: Surface Mount (exact match required)
Type: Molded Tantalum Polymer (exact match required)

Substitute parts must maintain these core electrical and mechanical specifications. Variations in ESR (Equivalent Series Resistance) and maximum seated height are permissible within the constraints of the 1411 package footprint and functional requirements of the application.

Parameter Comparison

Parameter	T520B686M004ASE040 (Main)	T520B686M004ATE040 (KEMET)	T55B686M004C0070 (Vishay Sprague)
Manufacturer	KEMET	KEMET	Vishay Sprague
Capacitance	68 µF	68 µF	68 µF
Voltage Rating	4 V	4 V	4 V
Package / Case	1411 (3528 Metric)	1411 (3528 Metric)	1411 (3528 Metric)
Type	Molded	Molded	Molded
ESR @ 100kHz	40 mOhm	40 mOhm	70 mOhm
Operating Temperature	-55°C to 105°C	-55°C to 105°C	-55°C to 105°C
Tolerance	±20%	±20%	±20%
Mounting Type	Surface Mount	Surface Mount	Surface Mount
Height - Seated (Max)	0.079" (2.00 mm)	0.079" (2.00 mm)	0.083" (2.10 mm)
Moisture Sensitivity Level	3 (168 Hours)	3 (168 Hours)	3 (168 Hours)
Product Status	Obsolete	Active	Active
RoHS Status	Non-compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

T520B686M004ATE040 (KEMET) is the primary substitute for the obsolete T520B686M004ASE040. Both parts are from the same manufacturer series (KO-CAP® T520), share identical electrical specifications including 40 mOhm ESR at 100 kHz, and maintain the same physical dimensions. The T520B686M004ATE040 is currently in active production status and is ROHS3 compliant, addressing regulatory requirements that the original part does not meet. The primary difference is packaging format: the substitute is supplied in Tape & Reel (TR) configuration versus the original's unspecified packaging.

T55B686M004C0070 (Vishay Sprague) serves as a secondary substitute from an alternative manufacturer. This part maintains electrical and mechanical compatibility with the main part across capacitance, voltage rating, package type, and operating temperature range. The ESR specification differs at 70 mOhm versus 40 mOhm at 100 kHz, and the maximum seated height is 0.083" (2.10 mm) compared to 0.079" (2.00 mm). Both the T520B686M004ATE040 and T55B686M004C0070 are ROHS3 compliant and REACH unaffected, making either suitable for applications requiring regulatory compliance.

Frequently Asked Questions (FAQ)

Q: Can the T520B686M004ATE040 be used as a direct replacement for the T520B686M004ASE040?

A: Yes. Both parts share identical capacitance (68 µF), voltage rating (4 V), package type (1411 / 3528 Metric), ESR (40 mOhm @ 100 kHz), and operating temperature range (-55°C to 105°C). The primary difference is packaging format and product status. The T520B686M004ATE040 is actively manufactured and ROHS3 compliant.

Q: What is the significance of the ESR difference between the KEMET and Vishay Sprague parts?

A: The T520B686M004ATE040 specifies 40 mOhm ESR at 100 kHz, while the T55B686M004C0070 specifies 70 mOhm at the same frequency. ESR affects ripple current handling and thermal performance. Applications sensitive to ESR characteristics should evaluate whether the higher ESR of the Vishay part is acceptable for the intended circuit function.

Q: Are there physical compatibility concerns with the Vishay Sprague substitute?

A: The T55B686M004C0070 has a maximum seated height of 0.083" (2.10 mm) compared to 0.079" (2.00 mm) for the original part. This 0.004" (0.10 mm) difference must be evaluated against PCB layout constraints and clearance requirements in the target application.

Q: Why is the original part classified as obsolete?

A: The T520B686M004ASE040 is no longer manufactured by KEMET. The T520B686M004ATE040 represents the current production equivalent within the same series, offering improved regulatory compliance through ROHS3 certification.

Q: What is the Moisture Sensitivity Level (MSL) rating, and does it affect substitution?

A: All three parts carry MSL 3 (168 Hours) rating, indicating identical moisture sensitivity characteristics. This parameter does not differentiate the substitute parts from the original.

Q: Are both substitute parts suitable for new designs?

A: Yes. Both the T520B686M004ATE040 and T55B686M004C0070 are in active production status and carry ROHS3 compliance, making them appropriate for new designs. The choice between them depends on ESR requirements, height constraints, and manufacturer preference.

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