Ft s series Surge Capable Thick Film Non Inductive F e at u r e s The TFS Series has been specifically developed to absorb large Appropriate for medical surge protec- amounts of energy by efficient use of its compact mass. Ideal tion applications for medical surge protection applications, these thick film resis- Ideal to replace standard carbon com- tors offer non-inductive per formance in an axial package. position resistors Uses include power supply conversion, electron microscopes, Custom dimensions, values, toler- X-ray systems, high-resolution CRT displays, and geophysical ances and characteristics available instrument related products. series speciFications Type U (KV) Energy* (J) Power (W) TFSA 3 6 0.5 TFSB 3.5 9 0.5 TFSC 4 11 0.75 TFSD 7 33 1 TFSE 7 44 1.5 TFSF 11 55 2 *Published energy rating is for 10ms pulse. For shorter pulses energy rat- ing has to be derated according to Max. Individual Pulse Rating chart and Single Pulse Energy Rating considerations. characteristics Thick Film Resistive Element Notes Encapsulation Screen Printed Glass Momentary overload capability is 5 times rated power for 1 second or 2 times rated power for 5 seconds. Always verify designs with pulse and surge condi- Resistance Value 100 up to 100K tions through thorough testing of the design at maximum operating tempera- ture and maximum pulse loading (or some margin above maximum pulse Temperature Coefficient 100ppm/C loading). Damage to the resistor by excessive pulse loading is generally indicated by an Tolerance 1%, 2%, 5%, 10% increasing resistance of the resistor. -55C to +200C Operating Temperature Energy ratings are based on single pulses (at least 1 minute between pulses). Test VDE 0750 (Pulse Duration 10 msec) For multiple pulse applications the energy pulse rating should be reduced and the average power should not exceed the nominal power rating of the selected model. See Single Pulse Energy section for more information dimensions mm C A Type Watts A B C H E TFSA 0.5 9 5.5 10 0.7 1.3 ~ 1.6 B TFSB 0.5 11 5.5 10 0.7 1.3 ~ 1.6 TFSC 0.75 13 5.5 10 0.7 1.3 ~ 1.6 0.50mm TFSD 1 21 8 10 0.9 1.4 ~ 1.8 HE TFSE 1.5 21 10.5 10 0.9 1.4 ~ 1.8 TFSF 2 26 10.5 10 0.9 1.4 ~ 1.8 0.25mm (continued) 58 1-866-9-OHMITE Intl 1-847-258-0300 Fax 1-847-574-7522 www.ohmite.com info ohmite.comtFs series Surge Capable Thick Film Non Inductive single pulse energy rating Example Although Ohmites TFS Series resistors have been specially designed and developed to absorb much more energy than standard resistors, A 1F capacitor is charged to width of 1ms falls well above the pulses and transients require special consideration since they cause an 3.5kV and model TFSC, 1KOhm energy curve. The limit is actually instantaneous temperature rise in the resistor film. This application note has been selected. Model TFSC located around 25-30%. Model can guide you through these considerations. is rated for 4kV, so the peak volt- TFSC cannot be used for this For applications with transients, pulses age of 3.5kV is acceptable. application. or surges the following must be consid- 2 V t 1 A bigger model should be chosen, ered: V E = 2 R Ea = CV = 6.1J for example TFSD. Model TFSD, 2 1. Do not exceed the normal rated oper- 1KOhm, can be used for this ating voltage of the device. t ta = R C = 1 ms application because we have an 2. Using the figure at right, estimate the energy ratio Er of 18%, which is 1 6.1J 2 energy (Ea) and the pulse duration E = CV below the energy curve. Er = x 100 = 55% V 2 11J (ta) for a single pulse in your applica- 6.1J t = RC tion. Er = x 100 = 18% According to the pulse chart, an t 33J 3. Calculate the energy ratio in percent energy ratio of 55% for a pulse (Er) between the nominal energy rat- 2 ing of the model you have chosen V t V E = Maximum Individual Pulse Rating (see table) and the single pulse 3R energy in your application (Ea from 1000 t step 2) using the formula: Ea 2 Er = x 100 V V t Enominal E = 100 3R 4. Refer to the Pulse Chart. On this t chart find the point where the energy 10 E= Energy (joules) ratio (Er), found at step 3, and time t= Time (seconds) (ta) coincide. Qualify that this point V= Voltage (volts) 1 falls below the maximum pulse R= Resistance (ohms) energy curve. If the point is above C= Capacitance (farads) the curve a bigger model should be 0.1 chosen. 1s 10s 100s 1 ms 10 ms 100 ms Pulse Width ordering inFormation RoHS Compliant Standard Part Numbers for TFS Series 6 Joules 9 Joules 11 Joules 33 Joules 44 Joules 55 Joules TFSA100KJE Ohms Tol. 0.5 Watts 0.5 Watts 0.75 Watts 1 Watts 1.5 Watts 2 Watts Series Energy Rating Ohm Value Tolerance 100 1% TFSA100RFE joules Example: F = 1% 100 5% TFSB100RJE TFSD100RJE TFSF100RJE A= 6 D= 33 100R = 100 G = 2% 220 1% TFSA220RFE B= 9 E= 44 2K40 = 2400 J = 5% 270 5% TFSA270RJE TFSC270RJE TFSD270RJE TFSF270RJE K = 10% C= 11 F= 55 470 1% TFSA470RFE 470 5% TFSB470RJE TFSE470RJE 680 5% TFSA680RJE TFSC680RJE TFSE680RJE TFSF680RJE 750 5% TFSB750RJE TFSD750RJE TFSF750RJE 1,000 1% TFSA1K00FE 1,000 5% TFSA1K00JE TFSB1K00JE TFSC1K00JE TFSD1K00JE TFSE1K00JE TFSF1K00JE 1,500 5% TFSA1K50JE TFSC1K50JE TFSD1K50JE TFSF1K50JE 2,200 1% TFSA2K20FE 2,700 5% TFSB2K70JE TFSE2K70JE 4,700 1% TFSA4K70FE 4,700 5% TFSA4K70JE TFSC4K70JE TFSD4K70JE 4,990 1% TFSA4K99FE 5,000 5% TFSA75K0JE 6,800 5% TFSB6K80JE TFSE6K80JE 10,000 1% TFSA10K0FE 10,000 5% TFSA10K0JE TFSB10K0JE TFSC10K0JE TFSD10K0JE TFSF10K0JE 16,000 5% TFSF16K0JE 20,000 1% TFSA20K0FE TFSF20K0JE 20,000 5% TFSB20K0JE TFSD20K0JE 22,000 1% TFSA22K0FE 27,000 5% TFSA27K0JE TFSC27K0JE TFSE27K0JE 47,000 1% TFSA47K0FE 50,000 5% TFSA50K0JE TFSF51K0JE 51,000 5% TFSB51K0JE TFSC51K0JE TFSD51K0JE 75,000 5% TFSE75K0JE 100,000 1% TFSA100KFE 100,000 5% TFSB100KJE TFSC100KJE TFSD100KJE TFSF100KJE rev 7/19-2 1-866-9-OHMITE Intl 1-847-258-0300 Fax 1-847-574-7522 www.ohmite.com info ohmite.com 59 Energy Rating %