T491B686M006ZT Equivalent & Substitute Parts

Part Overview

The T491B686M006ZT is a 68 µF molded tantalum capacitor rated at 6.3 V with ±20% tolerance, manufactured by KEMET in the 1411 (3528 Metric) package. This part is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement. The component features 900 mOhm ESR at 100 kHz, operates across -55°C to 125°C, and maintains a 2000-hour lifetime rating at 125°C. Direct replacements and parametric equivalents are available from KEMET and alternative manufacturers.

Key Parameters

Parameter	Value
Capacitance	68 µF
Tolerance	±20%
Voltage Rating	6.3 V
Type	Molded Tantalum
ESR @ 100 kHz	900 mOhm
Package	1411 (3528 Metric)
Operating Temperature Range	-55°C to 125°C
Lifetime @ 125°C	2000 Hours
Mounting Type	Surface Mount
MSL Rating	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution eligibility is determined by strict adherence to the following parameters: capacitance value (68 µF), voltage rating (6.3 V), package type (1411/3528 Metric), ESR specification (900 mOhm), operating temperature range (-55°C to 125°C), and lifetime rating (2000 Hrs @ 125°C). Tolerance variations (±20% vs. ±10%) are permitted as parametric equivalents when all other electrical and mechanical specifications remain identical. Substitute parts are grouped into two categories: direct manufacturer equivalents from KEMET with identical tolerance, and parametric equivalents from KEMET and alternative manufacturers (KYOCERA AVX, Cal-Chip Electronics) with tighter tolerance specifications.

Parameter Comparison

Part Number	Manufacturer	Capacitance	Tolerance	Voltage	ESR @ 100 kHz	Package	Temp Range	Lifetime @ 125°C	Status	RoHS	MSL
T491B686M006ZT	KEMET	68 µF	±20%	6.3 V	900 mOhm	1411	-55 to 125°C	2000 Hrs	Obsolete	ROHS3	1
T491B686M006AT	KEMET	68 µF	±20%	6.3 V	900 mOhm	1411	-55 to 125°C	2000 Hrs	Active	ROHS3	1
T491B686M006AT4280	KEMET	68 µF	±20%	6.3 V	900 mOhm	1411	-55 to 125°C	2000 Hrs	Active	ROHS3	1
T491B686K006AH	KEMET	68 µF	±10%	6.3 V	900 mOhm	1411	-55 to 125°C	2000 Hrs	Active	Non-compliant	1
T491B686K006AT2478	KEMET	68 µF	±10%	6.3 V	900 mOhm	1411	-55 to 125°C	2000 Hrs	Active	ROHS3	1
T491B686K006AT4280	KEMET	68 µF	±10%	6.3 V	900 mOhm	1411	-55 to 125°C	2000 Hrs	Active	ROHS3	1
TAJB686K006ANJ	KYOCERA AVX	68 µF	±10%	6.3 V	900 mOhm	1411	-55 to 125°C	2000 Hrs	Active	ROHS3	1
TAJB686K006RNJV	KYOCERA AVX	68 µF	±10%	6.3 V	900 mOhm	1411	-55 to 125°C	2000 Hrs	Active	ROHS3	3
TAJB686K006SNJ	KYOCERA AVX	68 µF	±10%	6.3 V	900 mOhm	1411	-55 to 125°C	2000 Hrs	Active	ROHS3	1
TAJB686M006BNJ	KYOCERA AVX	68 µF	±20%	6.3 V	900 mOhm	1411	-55 to 125°C	2000 Hrs	Active	ROHS3	1
TCKOJ686BT	Cal-Chip Electronics	68 µF	±10%	6.3 V	900 mOhm	1411	-55 to 125°C	2000 Hrs	Active	ROHS3	1

Engineering Selection Recommendations

For applications requiring direct functional replacement with identical tolerance specifications, T491B686M006AT and T491B686M006AT4280 are active KEMET alternatives with ROHS3 compliance and unlimited MSL rating. Both parts maintain the ±20% tolerance of the original T491B686M006ZT.

For designs where tighter tolerance (±10%) is acceptable, KEMET offers T491B686K006AT2478 and T491B686K006AT4280 with ROHS3 compliance. KYOCERA AVX provides parametric equivalents TAJB686K006ANJ, TAJB686K006SNJ, and TAJB686M006BNJ, all with active product status and ROHS3 compliance. TAJB686K006RNJV is available with MSL-3 rating for applications with extended moisture exposure requirements.

Cal-Chip Electronics TCKOJ686BT offers high inventory availability (56,800 pcs) with ±10% tolerance, ROHS3 compliance, and active status. All substitute parts maintain identical electrical performance, thermal characteristics, and mechanical compatibility with the original specification.

Frequently Asked Questions (FAQ)

Q: Can T491B686K006AT2478 replace T491B686M006ZT directly? A: Yes. Both parts share identical capacitance (68 µF), voltage rating (6.3 V), package (1411), ESR (900 mOhm), and thermal specifications. The tolerance difference (±10% vs. ±20%) represents a tighter specification, making this part functionally compatible. T491B686K006AT2478 is active and ROHS3 compliant.

Q: What is the difference between KEMET and KYOCERA AVX substitutes? A: Both manufacturers provide equivalent electrical and mechanical specifications. KYOCERA AVX parts (TAJ series) are active alternatives with identical performance parameters. Selection depends on supply chain availability and procurement preferences. All listed alternatives maintain the same package, capacitance, voltage, and ESR characteristics.

Q: Is TAJB686K006RNJV suitable for high-moisture environments? A: TAJB686K006RNJV carries MSL-3 rating (168 hours), compared to MSL-1 (unlimited) for most alternatives. MSL-3 requires controlled moisture exposure during storage and handling. For applications with standard moisture conditions, MSL-1 rated parts are recommended.

Q: Why is T491B686M006ZT obsolete? A: The original part is no longer manufactured by KEMET. Active alternatives with identical specifications are available, including T491B686M006AT from the same manufacturer and series.

Q: Can I use Cal-Chip TCKOJ686BT in production? A: Yes. TCKOJ686BT meets all electrical and mechanical requirements with ±10% tolerance, ROHS3 compliance, and active product status. High inventory availability (56,800 pcs) supports production requirements.

Q: Are all substitute parts in the same 1411 package? A: Yes. All listed alternatives use the 1411 (3528 Metric) package with identical dimensions (0.138" L × 0.110" W, 2.10 mm max height), ensuring mechanical compatibility with the original design.

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