RMCS0805FT1K21 Equivalent & Substitute Parts

Part Overview

The RMCS0805FT1K21 is a 1.21 kOhms ±1% 0.125W thick film chip resistor in 0805 (2012 Metric) package manufactured by Stackpole Electronics Inc. This anti-sulfur resistor operates across -55°C to 155°C and is ROHS3 compliant with unlimited moisture sensitivity rating. The part is active in production with 840 units currently in stock. Substitute parts are identified to provide design flexibility, alternative sourcing options, and compatibility with specific application requirements such as automotive qualification or enhanced power ratings.

Substiute Parts

RMCS0805FT1K21

Stackpole Electronics IncIn Stock: 869RMCS0805FT1K21 Datasheet

Current PartRFQ

RMCF0805FT1K21

Stackpole Electronics IncIn Stock: 229452RMCF0805FT1K21 Datasheet

MFR RecommendedRFQ

AC0805FR-071K21L

YAGEOIn Stock: 6951AC0805FR-071K21L Datasheet

MFR RecommendedRFQ

CRCW08051K21FKEA

Vishay DaleIn Stock: 9054CRCW08051K21FKEA Datasheet

MFR RecommendedRFQ

CRCW08051K21FKEAHP

Vishay DaleIn Stock: 80597CRCW08051K21FKEAHP Datasheet

MFR RecommendedRFQ

CRCW08051K21FKTA

Vishay DaleIn Stock: 5864CRCW08051K21FKTA Datasheet

MFR RecommendedRFQ

ERJ-6ENF1211V

Panasonic Electronic ComponentsIn Stock: 128499ERJ-6ENF1211V Datasheet

MFR RecommendedRFQ

RC0805FR-071K21L

YAGEOIn Stock: 337308RC0805FR-071K21L Datasheet

MFR RecommendedRFQ

RCS08051K21FKEA

Vishay DaleIn Stock: 10737RCS08051K21FKEA Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility is determined by matching the following critical parameters: resistance value (1.21 kOhms), tolerance (±1%), package type (0805), composition (thick film), temperature coefficient (±100ppm/°C), and operating temperature range (-55°C to 155°C). All identified substitutes meet these core electrical and mechanical specifications.

Substitute parts are grouped into two categories based on power rating:

Category 1: 0.125W (1/8W) Rating — Direct electrical equivalents with identical power dissipation capacity. These include standard industrial-grade and automotive AEC-Q200 qualified variants.

Category 2: 0.5W (1/2W) Rating — Enhanced power rating substitutes suitable for applications requiring higher pulse withstanding capability. These parts maintain all other electrical parameters while providing increased thermal headroom.

Parameter Comparison

Engineering Selection Recommendations

For Standard Industrial Applications: RMCS0805FT1K21 (original part) or RC0805FR-071K21L provide equivalent performance with moisture-resistant characteristics. Both maintain ROHS3 compliance and unlimited moisture sensitivity rating.

For Automotive Applications: RMCF0805FT1K21, AC0805FR-071K21L, CRCW08051K21FKEA, ERJ-6ENF1211V, and RCS08051K21FKEA are AEC-Q200 qualified alternatives. These parts satisfy automotive qualification requirements while maintaining electrical specifications.

For Enhanced Power Dissipation: CRCW08051K21FKEAHP and RCS08051K21FKEA offer 0.5W (1/2W) power rating with pulse withstanding capability. These are suitable for applications requiring higher thermal margin while maintaining the same resistance and tolerance values.

Compliance Consideration: CRCW08051K21FKTA is AEC-Q200 qualified but is RoHS non-compliant and REACH affected. Selection of this part requires verification against design compliance requirements.

Height-Constrained Designs: CRCW08051K21FKEA and CRCW08051K21FKEAHP offer the lowest seated height (0.020"), suitable for space-constrained PCB layouts.

Frequently Asked Questions (FAQ)

Q: Can RMCS0805FT1K21 be replaced with any of the listed substitutes?

A: Yes, all listed parts share the same resistance (1.21 kOhms), tolerance (±1%), package (0805), and operating temperature range (-55°C to 155°C). Substitution is electrically valid provided the application does not require specific certifications or compliance attributes unique to the original part.

Q: What is the difference between 0.125W and 0.5W rated parts?

A: Power rating indicates maximum continuous power dissipation. The 0.5W variants (CRCW08051K21FKEAHP, RCS08051K21FKEA) provide higher thermal capacity and pulse withstanding capability. Selection depends on circuit power requirements; oversizing is acceptable but unnecessary for low-power applications.

Q: Are all substitutes AEC-Q200 qualified?

A: No. RMCS0805FT1K21 and RC0805FR-071K21L are not AEC-Q200 qualified. All other listed substitutes carry AEC-Q200 certification. Automotive applications requiring this qualification must select from the AEC-Q200 qualified subset.

Q: Does package height variation affect PCB assembly?

A: Package height ranges from 0.020" to 0.028" (0.50mm to 0.70mm). For standard PCB designs, this variation is negligible. Height-critical applications (such as low-profile assemblies) should verify compatibility with specific design constraints.

Q: What is the significance of ROHS3 compliance?

A: ROHS3 compliance indicates the part meets Restriction of Hazardous Substances directive requirements. Most substitutes are ROHS3 compliant; CRCW08051K21FKTA is the exception (RoHS non-compliant). Design compliance requirements determine whether this attribute is mandatory.

Q: Can moisture-resistant variants be used interchangeably with standard variants?

A: Yes. Moisture-resistant features (AC0805FR-071K21L, RC0805FR-071K21L) provide enhanced environmental protection but do not alter electrical performance. These variants are suitable for all applications where standard parts are acceptable.