RMCS1206FT1K21 Equivalent & Substitute Parts

Part Overview

The RMCS1206FT1K21 is a 1.21 kOhms ±1% 0.25W thick film chip resistor in 1206 (3216 Metric) package manufactured by Stackpole Electronics Inc. This anti-sulfur resistor operates across -55°C to 155°C with a temperature coefficient of ±100ppm/°C. The part is ROHS3 compliant with unlimited moisture sensitivity rating (MSL 1). Substitute parts are necessary when the original part is unavailable, when design requirements demand automotive-grade certification, or when enhanced pulse withstanding capability is required.

Substiute Parts

RMCS1206FT1K21

Stackpole Electronics IncIn Stock: 1135RMCS1206FT1K21 Datasheet

Current PartRFQ

RMCF1206FT1K21

Stackpole Electronics IncIn Stock: 25697RMCF1206FT1K21 Datasheet

MFR RecommendedRFQ

AC1206FR-071K21L

YAGEOIn Stock: 5133AC1206FR-071K21L Datasheet

MFR RecommendedRFQ

CR1206-FX-1211ELF

Bourns Inc.In Stock: 45840CR1206-FX-1211ELF Datasheet

MFR RecommendedRFQ

CRCW12061K21FKEA

Vishay DaleIn Stock: 39106CRCW12061K21FKEA Datasheet

MFR RecommendedRFQ

CRCW12061K21FKEAHP

Vishay DaleIn Stock: 8904CRCW12061K21FKEAHP Datasheet

MFR RecommendedRFQ

CRCW12061K21FKTA

Vishay DaleIn Stock: 5870CRCW12061K21FKTA Datasheet

MFR RecommendedRFQ

ERJ-8ENF1211V

Panasonic Electronic ComponentsIn Stock: 55477ERJ-8ENF1211V Datasheet

MFR RecommendedRFQ

ERJ-P08F1211V

Panasonic Electronic ComponentsIn Stock: 3986ERJ-P08F1211V Datasheet

MFR RecommendedRFQ

RC1206FR-071K21L

YAGEOIn Stock: 282137RC1206FR-071K21L Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the RMCS1206FT1K21 is determined by strict equivalence in the following parameters: resistance value (1.21 kOhms), tolerance (±1%), package type (1206), composition (thick film), operating temperature range (-55°C to 155°C), and temperature coefficient (±100ppm/°C). All substitute parts maintain these core electrical and mechanical specifications.

Substitute parts are grouped into two categories:

Category 1: Standard 0.25W (1/4W) Equivalents — Direct functional replacements with identical power rating. These parts include RMCF1206FT1K21 (Stackpole, automotive AEC-Q200), AC1206FR-071K21L (YAGEO, automotive AEC-Q200 with moisture resistance), CR1206-FX-1211ELF (Bourns, moisture resistant), CRCW12061K21FKEA (Vishay Dale, automotive AEC-Q200), CRCW12061K21FKTA (Vishay Dale, automotive AEC-Q200), ERJ-8ENF1211V (Panasonic, automotive AEC-Q200), and RC1206FR-071K21L (YAGEO, moisture resistant).

Category 2: Enhanced Power Rating (0.75W/3/4W and 0.667W/2/3W) — Parts with higher power dissipation capability in the same package. These include CRCW12061K21FKEAHP (Vishay Dale, 0.75W with pulse withstanding) and ERJ-P08F1211V (Panasonic, 0.667W with pulse withstanding). These are suitable when circuit requirements demand increased power handling.

Parameter Comparison

Engineering Selection Recommendations

For applications requiring ROHS3 compliance and active product status, RMCF1206FT1K21, AC1206FR-071K21L, CRCW12061K21FKEA, and RC1206FR-071K21L are suitable direct replacements. RMCF1206FT1K21 maintains the same manufacturer as the original part with automotive AEC-Q200 certification added.

For automotive applications requiring AEC-Q200 certification, select from RMCF1206FT1K21, AC1206FR-071K21L, CRCW12061K21FKEA, CRCW12061K21FKTA, or ERJ-8ENF1211V. Note that ERJ-8ENF1211V carries "Not For New Designs" status and should be avoided in new development.

CRCW12061K21FKTA is not recommended due to RoHS non-compliance and REACH affected status, despite maintaining active product status and automotive certification.

For circuits requiring enhanced pulse withstanding capability, CRCW12061K21FKEAHP (0.75W) and ERJ-P08F1211V (0.667W) provide higher power dissipation in the same 1206 package while maintaining all core electrical parameters and automotive AEC-Q200 certification.

Frequently Asked Questions (FAQ)

Q: Can I use a 0.75W or 0.667W rated resistor as a direct replacement for the 0.25W RMCS1206FT1K21?

A: Yes. Higher power-rated resistors in the same package with identical resistance, tolerance, and temperature specifications are functionally compatible. The circuit will operate within design parameters. The higher power rating provides additional thermal margin but does not alter electrical performance at the specified 0.25W operating point.

Q: What is the difference between anti-sulfur and moisture-resistant features?

A: Anti-sulfur protection addresses corrosion from sulfur-containing environments. Moisture-resistant formulations address water ingress and humidity exposure. Both are thick film protection mechanisms. Selection depends on the specific environmental conditions of the application.

Q: Are all substitute parts available in the same physical dimensions?

A: All parts share the 1206 (3216 Metric) package designation. However, seated height varies slightly: RMCS1206FT1K21 and AC1206FR-071K21L are 0.026" (0.65mm), CR1206-FX-1211ELF is 0.030" (0.75mm), and others are 0.024" to 0.028". These variations are within standard PCB assembly tolerances for 1206 components.

Q: Why should I avoid ERJ-8ENF1211V despite its availability?

A: ERJ-8ENF1211V carries "Not For New Designs" product status from Panasonic. This designation indicates the manufacturer is phasing out the part. New designs should select from parts with "Active" status to ensure long-term supply chain stability.

Q: Is automotive AEC-Q200 certification required for my application?

A: AEC-Q200 certification is required only for automotive applications subject to automotive industry standards. For general industrial or consumer applications, non-certified equivalents such as CR1206-FX-1211ELF or RC1206FR-071K21L are functionally equivalent and suitable.

Q: What is the significance of ROHS3 compliance?

A: ROHS3 compliance indicates the part meets Restriction of Hazardous Substances Directive requirements, restricting lead and other hazardous materials. All recommended substitutes except CRCW12061K21FKTA are ROHS3 compliant. ROHS3 compliance is mandatory for products sold in the European Union and increasingly required globally.