RUSBF110-AP Equivalent & Substitute Parts

Part Overview

The RUSBF110-AP is a polymeric PTC resettable fuse manufactured by Littelfuse Inc. in the PolySwitch® RUSBF series. This component provides overcurrent protection with a 16V maximum voltage rating and 1.1A hold current specification. The part is currently listed as obsolete, making identification of suitable substitutes necessary for ongoing circuit protection applications requiring equivalent electrical and mechanical characteristics.

Key Parameters

Parameter	Value
Voltage - Max	16V
Current - Hold (Ih) (Max)	1.1 A
Current - Trip (It)	2.2 A
Current - Max	40 A
Time to Trip	2.3 s
Resistance - Initial (Ri) (Min)	50 mOhms
Resistance - Post Trip (R1) (Max)	140 mOhms
Operating Temperature	-40°C ~ 85°C
Mounting Type	Through Hole
Package / Case	Radial, Disc
Lead Spacing	0.199" (5.05mm)

Substitute Part Grouping Explanation

Substitution of the RUSBF110-AP is determined by strict equivalence across electrical protection parameters and mechanical form factor. The critical substitution criteria are:

Voltage rating: 16V maximum
Hold current: 1.1A maximum
Trip current: 2.2A
Time to trip: 2.3 seconds
Initial resistance: 50 mOhms minimum
Post-trip resistance: 140 mOhms maximum
Mounting configuration: Through hole radial disc package
Lead spacing: 0.199" (5.05mm)

The RUSBF110-2 meets all these electrical and mechanical specifications, establishing it as a direct equivalent for the obsolete RUSBF110-AP.

Parameter Comparison

Parameter	RUSBF110-AP	RUSBF110-2
Manufacturer	Littelfuse Inc.	Littelfuse
Series	PolySwitch®, RUSBF	PolySwitch®, RUSBF
Product Status	Obsolete	Active
Type	Polymeric	Polymeric
Voltage - Max	16V	16V
Current - Hold (Ih) (Max)	1.1 A	1.1 A
Current - Trip (It)	2.2 A	2.2 A
Current - Max	40 A	40 A
Time to Trip	2.3 s	2.3 s
Resistance - Initial (Ri) (Min)	50 mOhms	50 mOhms
Resistance - Post Trip (R1) (Max)	140 mOhms	140 mOhms
Operating Temperature	-40°C ~ 85°C	-40°C ~ 85°C
Mounting Type	Through Hole	Through Hole
Package / Case	Radial, Disc	Radial, Disc
Size / Dimension	0.291" L x 0.118" W (7.40mm x 3.00mm)	0.291" Dia x 0.118" T (7.40mm x 3.00mm)
Height - Seated (Max)	0.559" (14.20mm)	0.559" (14.20mm)
Lead Spacing	0.199" (5.05mm)	0.199" (5.05mm)
Approval Agency	CSA, TUV, UL	CSA, TUV, UL
RoHS Status	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

The RUSBF110-2 is the direct substitute for the obsolete RUSBF110-AP. Both components are manufactured by Littelfuse within the PolySwitch® RUSBF series and share identical electrical protection characteristics and mechanical dimensions. The RUSBF110-2 maintains active product status, ensuring ongoing availability and supply chain continuity. Both parts carry equivalent regulatory approvals (CSA, TUV, UL) and maintain ROHS3 compliance. The primary distinction is packaging format: RUSBF110-AP is supplied in standard packaging, while RUSBF110-2 is available in cut tape format. This packaging difference does not affect electrical performance or mechanical compatibility in through-hole applications.

Frequently Asked Questions (FAQ)

Q: Can RUSBF110-2 be used as a direct replacement for RUSBF110-AP in existing designs?

A: Yes. The RUSBF110-2 provides identical electrical protection parameters and mechanical form factor. Through-hole mounting compatibility is maintained across both parts.

Q: What is the difference between the two part numbers?

A: The primary difference is product status and packaging. RUSBF110-AP is obsolete; RUSBF110-2 is active production. RUSBF110-2 is supplied in cut tape packaging, while RUSBF110-AP was supplied in standard packaging. Electrical and mechanical specifications are identical.

Q: Are there any compliance or certification differences?

A: No. Both parts carry identical regulatory approvals (CSA, TUV, UL) and maintain ROHS3 compliance status.

Q: Will the lead spacing and mounting footprint remain the same?

A: Yes. Both parts maintain 0.199" (5.05mm) lead spacing and identical radial disc package dimensions, ensuring PCB footprint compatibility.

Q: Is the operating temperature range the same?

A: Yes. Both parts operate across the identical temperature range of -40°C to 85°C.

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