Radial Leaded PTC 0ZRS Series 0ZRS Series RoHS 2 Compliant Product Features - Very Low resistance, Very High hold current, Solid state, Radial leaded product ideal for up to 32V and Operating temperatures up to 125C. - AEC-Q Compliant - Meets Bel automotive qualification* * - Largely based on internal AEC-Q test plan Operating (Hold Current) Range 500mA - 10A Maximum Voltage 32V Temperature Range -40C to 125C Agency Approval TUV (Std. EN/IEC 60738-1-1 and EN/IEC 60730-1, Cert. R50102187) UL Recognized Component (Std. UL1434, File E305051) AEC-Q Compliant LEAD FREE = HALOGEN FREE = Electrical Characteristics (23 ) Max Time to Trip Resistance Tolerance Agency Approvals Hold Trip Rated Max Typical Part Number Current Current Voltage Current Power Current Time Rmin R1max (Bulk) IH, A IT, A Vmax, Vdc Imax, A Pd, W A Sec Ohms Ohms A 0ZRS0050FF1E 0.5 1.0 32 100 0.9 2.5 3.0 0.3500 1.1000 Y Y 100 B 0ZRS0070FF1E 0.7 1.4 32 1.4 3.5 3.2 0.2300 0.8000 Y Y C 0ZRS0100FF1E 1.0 1.9 32 100 1.4 5.0 6.2 0.1500 0.4300 Y Y 100 D 0ZRS0200FF1E 2.0 4.0 32 2.2 10.0 5.5 0.0650 0.2500 Y Y E 0ZRS0300FF1A 3.0 6.0 32 100 3.2 15.0 5.0 0.0350 0.1100 Y Y F 0ZRS0500FF1A 5.0 10.0 32 100 5.3 25.0 9.0 0.0150 0.0400 Y Y G 0ZRS0750FF1A 7.5 15.0 32 100 6.5 37.5 13.0 0.0074 0.0230 Y Y H 0ZRS1000FF1A 10.0 20.0 32 100 7.0 50.0 15.0 0.0060 0.0160 Y Y IH Hold Current- The maximum current at which the device will not trip in still air at 23C. IT Trip current- The minimum current at which the device will trip in still air at 23C. Vmax Maximum voltage device can withstand at its rated current without suffering damage. Imax Maximum fault current device can withstand at rated voltage (Vmax) without damage. Pd Typical power dissipated by device when in tripped state in 23C still air environment. Rmin Minimum device resistance at 23C in initial un-soldered state. R1max Maximum device resistance at 23C, 1 hour after initial device trip, or after being soldered to PCB in end application. Specifications subject to change without notice belfuse.com/circuit-protection 2 / 4 Type 0ZRS Series PTCs Basic Theory of Operation / Tripped Resistance Explanation A Bel PTC consists of a block of polymeric material containing conductive carbon granules which is sandwiched between two conductive metal plates. When this polymer block reaches approximately 125C, either due to current passing through it via conductive chains of carbon particles or due to an external heat source it swells volumetrically. This expansion breaks apart a majority of the chains of carbon granules that run randomly between the two conductive plates. This behavior results in a sharp increase in resistance across the two plates which all but eliminates current flow through the device, allowing just enough residual current flow to maintain the blocks internal temperature at 125C. Once this tripped state current is cut off, the polymer brick cools and shrinks to its original size, thereby allowing its broken carbon chains to reestablish themselves and permit the part to return to its low resistance state. Once cooled to room ambient, the PTC will once again exhibit a resistance less than its R1max rating. At currents below the device IHOLD rating, AND at temperatures below 100C, the PTC maintains a resistance value below its R1 MAX rating. The catalog data for each device specifies aTypical Powe value. This is the power required to exactly match the heat lost by the tripped device to its ambient surroundings at 23C. By Ohm s Law, power can be stated as: W = E/R. Thus the approximate resistance of a Tripped PTC can be determined by: R = E/W, where is the voltage appearing across the PTC (usually the supply s open circuit voltage), and is the Typical Power value for the particular PTC. Since the PPTC acts to maintain a constant internal temperature, its apparent resistance will change based upon applied voltage and, to a lesser degree, ambient conditions. Consider the following example.... A PTC with a Typical Power of 1 watt protecting a circuit using a 60V supply will demonstrate an apparent, tripped resistance of: R = 60/1 = 3,600 ohms This same tripped device when used to protect a 12V circuit would now present an apparent resistance of: R = 12/1 = 144 ohms The value for Typical Power istypica because any physical factors that affect heat loss (such as ambient temperature or air convection) will somewhat alter the level of power that the PTC needs to maintain its internal temperature. In short, PTCs do not exhibit a constant, quantifiable tripped resistance value. Average Time Current Characteristic Curve at 23C The Average Time Current Characteristic Curve and Temperature Rerating Curve are affected by a number of variables and these curves are provided for guidance only. Specifications subject to change without notice Bel Fuse Inc. +1 201.432.0463 206 Van Vorst Street Bel.US.CS belf.com Jersey City, NJ 07302 USA belfuse.com/circuit-protection 2019 Bel Fuse, Inc. Rev. 0ZRS Sep2019