RLD30P090UFF Equivalent & Substitute Parts

Part Overview

The RLD30P090UFF is a polymeric PTC resettable fuse manufactured by Littelfuse Inc., part of the POLY-FUSE® RLD30 series. This component provides overcurrent protection at 30V with a 900 mA hold current rating in a through-hole radial disc package. The RLD30P090UFF is classified as obsolete, making identification of equivalent and substitute parts essential for ongoing design support and component procurement.

Substiute Parts

RLD30P090UFF

Littelfuse Inc.In Stock: 758RLD30P090UFF Datasheet

Current PartRFQ

RUEF090-AP

LittelfuseIn Stock: 1472RUEF090-AP Datasheet

DirectRFQ

30R090UPR

Littelfuse Inc.In Stock: 235230R090UPR Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the RLD30P090UFF is determined by strict equivalence across the following critical parameters:

• Voltage rating: 30V maximum
• Hold current (Ih): 900 mA maximum
• Trip current (It): 1.8 A
• Time to trip: 5.9 s
• Initial resistance (Ri): 70 mOhms minimum
• Post-trip resistance (R1): 220 mOhms maximum
• Operating temperature range: -40°C ~ 85°C
• Mounting configuration: Through hole radial disc
• Physical dimensions: 0.291" L x 0.118" W with 0.201" lead spacing
• RoHS3 compliance

Two substitute parts meet these criteria: RUEF090-AP and 30R090UPR. Both are manufactured by Littelfuse Inc. and maintain electrical and mechanical compatibility with the obsolete RLD30P090UFF.

Parameter Comparison

Engineering Selection Recommendations

Both RUEF090-AP and 30R090UPR are active production parts suitable for replacing the obsolete RLD30P090UFF.

RUEF090-AP is the preferred substitute. It maintains all critical electrical parameters and physical dimensions while offering expanded regulatory approvals (CQC, CSA, TUV, UL) compared to the original part. The RUEF series represents Littelfuse's current PolySwitch® product line for this performance class. Lead spacing is 0.199" (5.05mm), which differs minimally from the original 0.201" (5.10mm) and remains compatible with standard through-hole PCB layouts.

30R090UPR is an alternative substitute within the POLY-FUSE® 30R series. It matches the original part's lead spacing exactly at 0.201" (5.10mm) and maintains identical electrical characteristics. Regulatory approvals are limited to cURus and TUV, matching the original part's certification scope.

Both substitutes are available in cut tape packaging and carry ROHS3 compliance certification.

Frequently Asked Questions (FAQ)

Q: Can RUEF090-AP be used as a direct replacement for RLD30P090UFF?

A: Yes. RUEF090-AP meets all critical electrical and mechanical parameters: 30V voltage rating, 900 mA hold current, 1.8 A trip current, 5.9 s trip time, identical resistance specifications, and compatible physical dimensions. The 0.002" (0.05mm) difference in lead spacing is within standard PCB tolerance for through-hole mounting.

Q: What is the difference between RUEF090-AP and 30R090UPR?

A: Both parts are electrically equivalent. The primary differences are series designation (PolySwitch® RUEF versus POLY-FUSE® 30R) and regulatory approvals. RUEF090-AP includes broader certifications (CQC, CSA, UL in addition to TUV), while 30R090UPR matches the original part's certification scope (cURus, TUV). Lead spacing is identical at 0.201" (5.10mm) for 30R090UPR and 0.199" (5.05mm) for RUEF090-AP.

Q: Why is the RLD30P090UFF obsolete?

A: The RLD30P090UFF is classified as obsolete by Littelfuse. Active production has transitioned to the RUEF and 30R series, which offer equivalent performance with enhanced regulatory support and manufacturing continuity.

Q: Are there any thermal or environmental considerations when substituting?

A: Both substitute parts maintain the original operating temperature range of -40°C ~ 85°C. No additional thermal management is required. Both are ROHS3 compliant and suitable for equivalent environmental conditions.

Q: What is the lead spacing tolerance for PCB design?

A: The original RLD30P090UFF specifies 0.201" (5.10mm) lead spacing. RUEF090-AP has 0.199" (5.05mm) spacing, a 0.002" (0.05mm) difference. Standard PCB through-hole tolerances accommodate this variation. 30R090UPR maintains exact lead spacing at 0.201" (5.10mm) if zero-tolerance matching is required.