Phoenix do Brasil Ltda. FUSIBLE RESISTOR - NFR25 FEATURES • Metal film; • Fusible resistors; • Overload protection without risk of fire; • Wide range of overload currents; • Different forming styles available; • Defined interruption behavior (fusing time); • High stability, reliability and uniformity characteristics; • Suitable for protection circuit boards and designs; • Low and medium power requirements; • Various packing and taping configurations; • Defined pulse loading capabilities (repetitive and single pulse). MARKET SEGMENTS AND APPLICATIONS Industry sector Application segment End-user equipment Power supplies Industrial Controls Power system control Central heating controls Line protection resistor Telecom Data Communication Power supplies Modems Amplifiers Consumer Sound & Vision TV VCR TECHNOLOGY A homogeneous film of metal alloy is deposited on a high-grade ceramic body. After a helical groove has been cut in the resistive layer, tinned connecting wires of electrolytic copper are welded to the end-caps. The resistors are coated with a grey, flame retardant lacquer, which provides electrical, mechanical and climatic protection. The encapsulation is resistant to all cleaning solvents in accordance with “MIL-STD-202E, method 215” and “IEC 60068-2-45”. NFR25 Revision on 2002/07/11     PHOENIX DO BRASIL LTDA. All rights are reserved. Reproduction whole or in part is Without the written consent of the copyright owner. Page 1 of 10 Phoenix do Brasil Ltda. QUICK REFERENCE DATA NFR25 DESCRIPTION (E-24 serie) Cu-lead Resistance range 0.22Ω to 15kΩ Resistance tolerance ± 5% Maximum dissipation at Tamb = 70ºC 0.33W Thermal resistance (Rth) 240 K/W Temperature coefficient 0.22Ω ≤ R ≤ 15Ω ≤ ±200ppm/ºC 15Ω < R ≤ 15kΩ ≤ ±100ppm/ºC Limiting voltage (DC or RMS) 250V (1) Rated voltage Pn x R Climatic category (IEC 60068) 55/155/56 Basic specifications IEC 60115-1 and 60115-2 Stability after: Load ΔR/R max.: ±1% + 0.05Ω Climatic tests ΔR/R max.: ±1% + 0.05Ω Resistance to soldering heat ΔR/R max.: ±0.25% + 0.05Ω Note: 1- Maximum rated voltage is the “Limiting voltage”. NFR25 Revision on 2002/07/11     PHOENIX DO BRASIL LTDA. All rights are reserved. Reproduction whole or in part is Without the written consent of the copyright owner. Page 2 of 10 Phoenix do Brasil Ltda. MECHANICAL DATA L2 L1 Table 1 Mass per Type A φ φ φ φD max. L1 max. L2 max φ φ φ φd |||| B1-B2|||| 100units (g) NFR25 52 +1.5/-0 2.5 6.5 7.5 0.58 ± 0.05 1.2 21 Dimensions in mm MOUNTING The resistors are suitable for processing on automatic insertion equipment, cutting and bending machines. NFR25 Revision on 2002/07/11     PHOENIX DO BRASIL LTDA. All rights are reserved. Reproduction whole or in part is Without the written consent of the copyright owner. Page 3 of 10 Phoenix do Brasil Ltda. ELECTRICAL CHARACTERISTICS DERATING The power that resistor can dissipate depends on the operating temperature. Pmax X Tamb 120 100 80 60 40 20 0 -55 0 55 70 110 155 Tamb (ºC) Maximum dissipation (Pmax) in percentage of rated power as a function of the ambient temperature (Tamb). APPLICATION INFORMATION FOR HOT-SPOT AND SOLDER-SPOT Hot-spot Solder-spot Fig. 1 - Hot spot temperature rise (ΔT) Fig. 2 - Temperature rise (ΔT) at the lead as a function of dissipated power (soldering point) as a function of dissipated power at various lead lengths after mounting Note: The maximum permissible hot-spot temperature is 155ºC NFR25 Revision on 2002/07/11     PHOENIX DO BRASIL LTDA. All rights are reserved. Reproduction whole or in part is Without the written consent of the copyright owner. Page 4 of 10 Pmax % Prated Phoenix do Brasil Ltda. FUSING CHARACTERISTIC The resistors will fuse without the risk of fire and within an indicated range of overload. Fusing means that resistive value of the resistor increases at least 100 times; see Figs. 3, 4 and 5. The fusing characteristic is measured under constant voltage. This graph is based on measured data witch may deviate according to the application. Fig. 3 - Fusing Fig. 4 - Fusing Fig. 5 - Fusing characteristic: characteristic: ≤ 1Ω characteristic: 1Ω ≤ R ≤15Ω 15Ω