MXP190BB Polymeric PTC Resettable Fuse Equivalent & Substitute Parts

Part Overview

The MXP190BB is a polymeric PTC resettable fuse manufactured by Littelfuse Inc., rated for 6V at 1.9A hold current with a strap mounting configuration. This component is classified as obsolete product status. Due to its obsolete designation and limited availability in strap form factor, equivalent substitute parts are necessary for new designs and ongoing production requirements. Suitable alternatives are available in modern surface mount packages with active product status and improved thermal characteristics.

Key Parameters

Parameter	MXP190BB Value
Voltage - Max	6V
Current - Hold (Ih) (Max)	1.9 A
Current - Trip (It)	4.9 A
Current - Max	50 A
Time to Trip	2 s
Resistance - Initial (Ri) (Min)	7 mOhms
Resistance - Post Trip (R1) (Max)	24 mOhms
Type	Polymeric
Mounting Type	User Defined (Strap)
Package / Case	Strap
Product Status	Obsolete
RoHS Status	ROHS3 Compliant
Approval Agency	CSA, TUV, UL

Substitute Part Grouping Explanation

Substitution of the MXP190BB is determined by the following electrical and mechanical criteria:

Voltage Compatibility: All substitute parts must maintain 6V maximum rating to ensure circuit protection at the same voltage threshold.

Current Hold (Ih) Range: The MXP190BB operates at 1.9A hold current. Substitute parts are grouped by current rating proximity. The closest electrical equivalents are 0603L175SLYR and 0805L175SLYR at 1.75A, and 0805L200SLTHYR at 2A, which bracket the original specification.

Current Trip (It) Characteristic: Trip current of 4.9A in the original part corresponds to substitute parts with trip currents ranging from 1A to 6A depending on hold current selection.

Resistance Profile: Initial resistance (Ri) and post-trip resistance (R1) vary across the substitute range. Lower current-rated parts exhibit higher resistance values; higher current-rated parts show lower resistance values.

Mounting Type: The original strap configuration is replaced by surface mount alternatives in 0402, 0603, and 0805 form factors, enabling integration into modern PCB designs.

Product Status: All substitute parts carry active product status, ensuring long-term availability and supply chain continuity.

Parameter Comparison

Part Number	Voltage (Max)	Ih (Max)	It	Ri (Min)	R1 (Max)	Time to Trip	Mounting Type	Package	Product Status
MXP190BB	6V	1.9 A	4.9 A	7 mOhms	24 mOhms	2 s	User Defined (Strap)	Strap	Obsolete
0603L100SLYR	6V	1 A	1.8 A	40 mOhms	120 mOhms	300 ms	Surface Mount	0603 (1608 Metric)	Active
0603L175SLYR	6V	1.75 A	4.6 A	5 mOhms	60 mOhms	600 ms	Surface Mount	0603 (1608 Metric)	Active
0805L175SLYR	6V	1.75 A	4.6 A	5 mOhms	55 mOhms	600 ms	Surface Mount	0805 (2012 Metric)	Active
0805L200SLTHYR	6V	2 A	4 A	5 mOhms	45 mOhms	1 s	Surface Mount	0805 (2012 Metric)	Active
0805L260SLTHYR	6V	2.6 A	5 A	3 mOhms	35 mOhms	4 s	Surface Mount	0805 (2012 Metric)	Active
0805L300SLWR	6V	3 A	6 A	3 mOhms	30 mOhms	5 s	Surface Mount	0805 (2012 Metric)	Active

Engineering Selection Recommendations

Primary Substitute: 0805L200SLTHYR provides the closest electrical match to MXP190BB with 2A hold current, 4A trip current, and 1 second trip time. This part maintains 6V rating, active product status, and cURus/TUV certifications. The 0805 package accommodates standard PCB assembly processes.

Alternative for Compact Designs: 0603L175SLYR offers 1.75A hold current in a smaller 0603 form factor. This selection is appropriate when PCB space is constrained and the 1.75A rating satisfies circuit requirements.

Higher Current Applications: 0805L260SLTHYR and 0805L300SLWR are suitable when circuit design permits higher hold current ratings. These parts provide lower resistance profiles and extended trip times.

Compliance Consideration: All recommended substitutes maintain ROHS3 compliance and carry active product status from Littelfuse Inc., ensuring regulatory alignment and supply chain stability.

Frequently Asked Questions (FAQ)

Q: Can the MXP190BB be directly replaced with a surface mount equivalent?

A: Direct mechanical replacement is not possible due to the strap form factor of the original part. However, electrical substitution is achievable through surface mount alternatives. PCB redesign is required to accommodate the new package form factor.

Q: Which substitute part is electrically closest to MXP190BB?

A: The 0805L200SLTHYR provides the closest electrical characteristics with 2A hold current versus 1.9A original, 4A trip current versus 4.9A original, and comparable resistance profiles. The 1 second trip time aligns with the 2 second original specification.

Q: What is the difference between 0603L175SLYR and 0805L175SLYR?

A: Both parts share identical electrical specifications at 1.75A hold current and 4.6A trip current. The difference is package size: 0603 (1.60mm x 0.80mm) versus 0805 (2.10mm x 1.35mm). Selection depends on available PCB real estate and assembly equipment capability.

Q: Are all substitute parts RoHS compliant?

A: Yes, all listed substitute parts are ROHS3 compliant and carry active product status, meeting current regulatory requirements and ensuring long-term availability.

Q: How does resistance affect substitute part selection?

A: Initial resistance (Ri) and post-trip resistance (R1) impact circuit performance during normal operation and fault conditions. Lower current-rated substitutes exhibit higher resistance values. Verify that the selected substitute's resistance profile does not introduce unacceptable voltage drop or thermal effects in the target application.

Q: What certifications do the substitute parts carry?

A: All substitute parts are certified by cURus and TUV. The original MXP190BB carried CSA, TUV, and UL certifications. Verify that the substitute part certifications meet your specific application requirements.

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