MICROSMD600LR-2 PTC Resettable Fuse Equivalent & Substitute Parts

Part Overview

The MICROSMD600LR-2 is a Polymeric PTC Resettable Fuse manufactured by Littelfuse, rated for 6V at 6A hold current in a 1210 (3225 Metric) surface mount package. This component is classified as Obsolete, making identification of active equivalent parts essential for ongoing design support and procurement.

PTC resettable fuses provide automatic overcurrent protection by increasing resistance when current exceeds the trip threshold, then resetting when the fault condition is removed. The obsolete status of the MICROSMD600LR-2 necessitates evaluation of active substitute parts that maintain electrical and mechanical compatibility.

Key Parameters

Parameter	Value
Voltage - Max	6V
Current - Hold (Ih)	6 A
Current - Trip (It)	12 A
Current - Max	50 A
Package / Case	1210 (3225 Metric), Concave
Mounting Type	Surface Mount
Operating Temperature Range	-40°C ~ 80°C
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution eligibility for the MICROSMD600LR-2 is determined by the following critical parameters:

Voltage rating of 6V maximum
Hold current (Ih) of 6A
Trip current (It) of 12A
Maximum current rating of 50A
1210 (3225 Metric) surface mount package with concave configuration
Surface mount assembly compatibility
ROHS3 compliance

The two identified substitute parts meet these core electrical and mechanical requirements while offering active product status and enhanced compliance certifications.

Parameter Comparison

Parameter	MICROSMD600LR-2	1210L600SLWR	PTSLR12106V600
Manufacturer	Littelfuse	Littelfuse Inc.	Eaton - Electronics Division
Series	PolySwitch® microSMD	POLY-FUSE® LoRho	PTSLR1210
Product Status	Obsolete	Active	Active
Voltage - Max	6V	6V	6V
Current - Hold (Ih)	6 A	6 A	6 A
Current - Trip (It)	12 A	12 A	12 A
Current - Max	50 A	50 A	50 A
Time to Trip	2 s	2 s	5 s
Resistance - Initial (Ri) Min	2 mOhms	1 mOhms	1 mOhms
Resistance - Post Trip (R1) Max	6.3 mOhms	10 mOhms	10 mOhms
Operating Temperature Range	-40°C ~ 80°C	-40°C ~ 85°C	-40°C ~ 85°C
Package / Case	1210 (3225 Metric), Concave	1210 (3225 Metric), Concave	1210 (3225 Metric), Concave
Size / Dimension	0.127" L x 0.102" W (3.22mm x 2.58mm)	0.127" L x 0.101" W (3.22mm x 2.58mm)	0.135" L x 0.110" W (3.43mm x 2.80mm)
Thickness (Max)	0.039" (1.00mm)	0.055" (1.40mm)	0.039" (1.00mm)
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Approval Agency	UL	cURus, TUV	cURus, TUV
Moisture Sensitivity Level (MSL)	2A (4 Weeks)	1 (Unlimited)	2A (4 Weeks)
ECCN	EAR99	EAR99	EAR99
HTSUS	8533.40.8070	8533.40.8070	8533.40.8070

Engineering Selection Recommendations

Both substitute parts are active products with ROHS3 compliance and international certifications (cURus, TUV), providing superior long-term availability compared to the obsolete MICROSMD600LR-2.

The 1210L600SLWR (Littelfuse POLY-FUSE® LoRho series) maintains the closest electrical performance to the original part with identical trip characteristics and offers unlimited moisture sensitivity rating. Physical dimensions are nearly identical to the MICROSMD600LR-2, with minimal thickness increase (0.055" vs 0.039").

The PTSLR12106V600 (Eaton PTSLR1210 series) meets all core electrical requirements with extended operating temperature range to 85°C. Physical dimensions are slightly larger (0.135" L x 0.110" W vs 0.127" L x 0.102" W), and time-to-trip is extended to 5 seconds compared to 2 seconds for the original part.

Both parts are suitable for direct substitution in applications where the specified electrical parameters and package footprint are primary selection criteria.

Frequently Asked Questions (FAQ)

Q: Can the 1210L600SLWR directly replace the MICROSMD600LR-2 in existing designs?

A: Yes. The 1210L600SLWR matches all critical electrical parameters (6V, 6A hold, 12A trip) and package configuration (1210 concave). Physical dimensions are nearly identical, with only a 0.016" thickness increase. PCB layout compatibility is maintained.

Q: What is the difference in trip response time between the substitute parts?

A: The 1210L600SLWR maintains the original 2-second trip time. The PTSLR12106V600 has a 5-second trip time. Selection depends on application-specific overcurrent response requirements.

Q: Are there physical footprint considerations when substituting the PTSLR12106V600?

A: The PTSLR12106V600 has slightly larger dimensions (0.135" L x 0.110" W) compared to the MICROSMD600LR-2 (0.127" L x 0.102" W). Verify PCB layout clearances before implementation. Thickness is identical at 0.039".

Q: What is the moisture sensitivity difference between the substitute parts?

A: The 1210L600SLWR has MSL 1 (unlimited storage), providing superior moisture protection. The PTSLR12106V600 has MSL 2A (4 weeks), matching the original part. Selection depends on storage and handling requirements.

Q: Do both substitute parts maintain the same operating temperature range?

A: The 1210L600SLWR and PTSLR12106V600 both extend the operating range to -40°C ~ 85°C, compared to the original -40°C ~ 80°C. This provides additional thermal margin for demanding applications.

Q: Are there resistance specification differences that affect circuit performance?

A: Initial resistance (Ri) and post-trip resistance (R1) differ slightly between parts. The 1210L600SLWR and PTSLR12106V600 have lower initial resistance (1 mOhms vs 2 mOhms) and higher post-trip resistance (10 mOhms vs 6.3 mOhms). Verify circuit performance in applications sensitive to these parameters.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message