RFS-35V221MI6#5 Equivalent & Substitute Parts

Part Overview

The RFS-35V221MI6#5 is a 220 µF, 35 V aluminum electrolytic capacitor in radial, can package manufactured by Elna America. This component is part of the RFS/SILMIC II series and is rated for 1000 hours at 85°C, with applications in audio circuits. The part is classified as obsolete, necessitating identification of equivalent and substitute components for ongoing design support and procurement.

Key Parameters

Parameter	Value
Capacitance	220 µF
Voltage Rating	35 V
Tolerance	±20%
Lifetime @ Temperature	1000 Hrs @ 85°C
Operating Temperature Range	-40°C ~ 85°C
Polarization	Polar
Ripple Current @ 120 Hz	550 mA
Lead Spacing	0.197" (5.00 mm)
Case Diameter	0.492" (12.50 mm)
Height (Seated Max)	0.984" (25.00 mm)
Mounting Type	Through Hole
Package Type	Radial, Can
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution of the RFS-35V221MI6#5 is determined by the following critical parameters:

Direct Equivalents (Same Voltage Rating - 35 V): Parts maintaining 35 V voltage rating, 220 µF capacitance, ±20% tolerance, and compatible through-hole radial package with 5.00 mm lead spacing qualify as direct substitutes. These parts preserve circuit voltage margins and thermal performance characteristics.

Upgraded Substitutes (Higher Voltage Rating - 100 V): Parts rated at 100 V with identical 220 µF capacitance, ±20% tolerance, and compatible mechanical dimensions function as upgraded alternatives. Higher voltage rating provides increased design margin and typically extends operational lifetime. These parts maintain the same lead spacing (5.00 mm) and radial can package format.

Compatibility Criteria:

Capacitance: 220 µF (fixed requirement)
Tolerance: ±20% (fixed requirement)
Polarization: Polar (fixed requirement)
Lead Spacing: 0.197" (5.00 mm) (fixed requirement)
Case Diameter: 0.492" (12.50 mm) (fixed requirement)
Mounting Type: Through Hole (fixed requirement)
Package: Radial, Can (fixed requirement)

Parameter Comparison

Part Number	Manufacturer	Capacitance	Voltage	Tolerance	Lifetime @ Temp	Operating Temp Range	Ripple Current @ 120 Hz	Case Dia	Height (Max)	Lead Spacing	Product Status
RFS-35V221MI6#5	Elna America	220 µF	35 V	±20%	1000 Hrs @ 85°C	-40°C ~ 85°C	550 mA	0.492" (12.50 mm)	0.984" (25.00 mm)	0.197" (5.00 mm)	Obsolete
UFG1V221MPM	Nichicon	220 µF	35 V	±20%	1000 Hrs @ 85°C	-40°C ~ 85°C	320 mA	0.394" (10.00 mm)	0.866" (22.00 mm)	0.197" (5.00 mm)	Obsolete
UFW1V221MPD	Nichicon	220 µF	35 V	±20%	2000 Hrs @ 85°C	-40°C ~ 85°C	370 mA	0.394" (10.00 mm)	0.492" (12.50 mm)	0.197" (5.00 mm)	Not For New Designs
UKW1V221MPD	Nichicon	220 µF	35 V	±20%	2000 Hrs @ 85°C	-40°C ~ 85°C	370 mA	0.394" (10.00 mm)	0.492" (12.50 mm)	0.197" (5.00 mm)	Not For New Designs
UFW2A221MHD	Nichicon	220 µF	100 V	±20%	2000 Hrs @ 85°C	-40°C ~ 85°C	600 mA	0.492" (12.50 mm)	0.984" (25.00 mm)	0.197" (5.00 mm)	Not For New Designs
UKW2A221MHD	Nichicon	220 µF	100 V	±20%	2000 Hrs @ 85°C	-40°C ~ 85°C	600 mA	0.492" (12.50 mm)	0.984" (25.00 mm)	0.197" (5.00 mm)	Not For New Designs
EKZE101ELL221MK25S	Chemi-Con	220 µF	100 V	±20%	5000 Hrs @ 105°C	-40°C ~ 105°C	625 mA	0.492" (12.50 mm)	1.043" (26.50 mm)	0.197" (5.00 mm)	Active

Engineering Selection Recommendations

For Direct Replacement (Same Voltage Class):

UFW1V221MPD and UKW1V221MPD are functionally equivalent to RFS-35V221MI6#5 at the 35 V voltage rating. Both parts maintain 220 µF capacitance, ±20% tolerance, and 5.00 mm lead spacing. These Nichicon components extend operational lifetime to 2000 hours at 85°C compared to the original 1000 hours, providing improved reliability. Both parts are classified as "Not For New Designs" but remain available for legacy system support. RoHS3 compliance is maintained across all three parts.

For Upgraded Performance (Higher Voltage Rating):

UFW2A221MHD and UKW2A221MHD provide 100 V voltage rating with identical mechanical dimensions to the original part (0.492" diameter, 0.984" height, 5.00 mm lead spacing). These upgrades deliver doubled voltage margin, extended 2000-hour lifetime at 85°C, and increased ripple current handling (600 mA @ 120 Hz versus 550 mA). Both maintain RoHS3 compliance and are suitable for circuits where voltage headroom is beneficial.

For Long-Term Reliability (Active Status):

EKZE101ELL221MK25S from Chemi-Con represents the only active-status alternative, offering 100 V rating, 5000-hour lifetime at 105°C, and extended operating temperature range to 105°C. This part maintains identical lead spacing and case diameter but has slightly increased height (1.043" versus 0.984"). RoHS3 compliance and REACH unaffected status are confirmed. This component is suitable for new designs requiring extended operational life and thermal margin.

Frequently Asked Questions (FAQ)

Q: Can UFG1V221MPM replace RFS-35V221MI6#5 directly?

A: UFG1V221MPM maintains the same 35 V voltage rating, 220 µF capacitance, ±20% tolerance, and 5.00 mm lead spacing. However, it has reduced case diameter (0.394" versus 0.492") and different height (0.866" versus 0.984"), requiring PCB layout verification. Ripple current rating is also lower at 320 mA versus 550 mA. Both parts are obsolete.

Q: What is the advantage of using 100 V rated parts instead of 35 V?

A: 100 V rated capacitors (UFW2A221MHD, UKW2A221MHD, EKZE101ELL221MK25S) provide doubled voltage safety margin in 35 V circuits. They typically offer extended lifetime ratings (2000 to 5000 hours at 85°C or higher) and improved ripple current handling. Mechanical compatibility is maintained with identical lead spacing and case diameter.

Q: Is EKZE101ELL221MK25S compatible with the original PCB layout?

A: EKZE101ELL221MK25S maintains identical lead spacing (5.00 mm) and case diameter (0.492") as RFS-35V221MI6#5. Height is slightly increased (1.043" versus 0.984"), which must be verified against PCB clearance and component placement constraints. All other mechanical and electrical parameters are compatible.

Q: Why are UFW1V221MPD and UKW1V221MPD marked "Not For New Designs"?

A: This designation indicates these parts are in mature or declining production phases. They remain available for legacy system support and replacement applications. For new circuit designs, EKZE101ELL221MK25S (active status) is the recommended choice.

Q: Can I use these capacitors interchangeably in audio applications?

A: All listed parts are rated for audio applications and maintain ±20% tolerance and polar configuration. Direct voltage-class substitutes (UFW1V221MPD, UKW1V221MPD) are functionally equivalent. Upgraded 100 V parts function in audio circuits with improved reliability margins. Ripple current ratings must be verified against actual circuit requirements.

Q: What is the difference between UFW2A221MHD and UKW2A221MHD?

A: Both parts are 100 V, 220 µF Nichicon capacitors with identical electrical specifications (2000 Hrs @ 85°C, 600 mA ripple current @ 120 Hz) and mechanical dimensions. They belong to different series (UFW versus UKW) but are functionally equivalent. Inventory availability and procurement lead times may differ.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. RFS-35V221MI6#5 and all listed substitute parts (UFG1V221MPM, UFW1V221MPD, UKW1V221MPD, UFW2A221MHD, UKW2A221MHD, EKZE101ELL221MK25S) are confirmed RoHS3 compliant. REACH status is unaffected for all parts.

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