CFS Series MELF Carbon Film Resistors (SMD Cylindrical)

What are CFS Series MELF Carbon Film Resistors (SMD Cylindrical)?

The CFS series are MELF (Metal Electrode Leadless Face) carbon film resistors in a cylindrical SMD format, constructed on a ceramic rod substrate with a carbon resistive film and insulation coating over the body. The cylindrical geometry distinguishes these devices from conventional flat chip resistors: the round cross-section means the component can be placed in either orientation without affecting performance, simplifying automated assembly and eliminating the polarity concerns associated with flat-bodied SMD parts. The ceramic rod core provides a stable, thermally robust base for the resistive film, and the specially plated end-cap electrodes deliver high solderability and greater mechanical strength than the terminations found on flat chip equivalents.

Three body sizes cover a power range from 1/4W to 2W. The CFS0204 (3.5mm × 1.4mm) is rated at 1/4W at 70°C with a maximum operating voltage of 250V and overload voltage of 500V. The CFS0207 (5.9mm × 2.2mm) is rated at 1/2W in standard form and 1W in the higher-rated variant, with corresponding voltage ratings of 300V and 350V operating and 600V and 700V overload. The CFS0309 (8.5mm × 3.2mm) is rated at 1W or 2W with a maximum operating voltage of 350V and overload voltage of 700V. All three models share the same resistance range of 1Ω to 1MΩ and are available in ±2% and ±5% tolerances, with an operating temperature range of −55°C to +155°C throughout.

A key advantage of the carbon film MELF construction is lower current noise compared to flat thick film chip resistors. This makes the CFS series preferable in low-level signal and measurement circuits where resistor noise would otherwise degrade signal integrity. Short-time overload capability is 2.5 times the rated continuous working voltage (RCWV) or the maximum overload voltage for 5 seconds, with a resistance change limit of ±1%. Endurance stability is ±3% after 1000 hours at 70°C under maximum working voltage. Damp heat with load stability is ±5% after 1000 hours at 40°C, 90–95% RH, and dry heat stability is ±2% after 1000 hours at +155°C.

The CFS series is fully compatible with reflow, flow and iron soldering processes. Solderability is guaranteed at 95% minimum coverage at 245°C for 3 seconds, and resistance to soldering heat is ±1% at 260°C for 10 seconds. Storage conditions are 25°C ±3°C and humidity below 80% RH. Packaging is supplied on 180mm (7") reels for the CFS0204 and CFS0207, with the CFS0309 additionally available on 330mm (13") reels, at quantities of 2000 to 3000 pieces per reel depending on body size. Performance is referenced to JIS-C 5201-1.

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Model: CFS
Resistor type: Power film
Description: Carbon film, MELF
Power Rating: 1/4W~2W
Resistance (Ω): 1~1M
Tolerance (%): ±2, ±5
TCR (ppm/C): 350~1000

Model: TNP25, TNP45
Resistor type: Power film
Description: SMD surge protection
Power Rating: 25W, 45W
Resistance (Ω): 0.1~51k
Tolerance (%): ±1
TCR (ppm/C): 100

Model: SMF
Resistor type: Power film
Description: Chip
Power Rating: 2W, 3W, 5W
Resistance (Ω): 10~20M
Tolerance (%): ±1, ±5
TCR (ppm/C): 100

Model: ARN
Resistor type: Aluminum nitride
Description: Chip
Power Rating: 1/2W, 1W, 2W, 6W
Resistance (Ω): 50~30.1k
Tolerance (%): ±0.1
TCR (ppm/C): 25, 50

Model: CRP
Resistor type: Aluminum nitride
Description: Chip
Power Rating: 2.4W, 3.5W
Resistance (Ω): 10~2k
Tolerance (%): ±1, ±5
TCR (ppm/C): 150