Surface Mount PTC 0ZTG Series 0ZTG Series 1812 Chip RoHS Compliant Operating (Hold Current) Range 1.1A Product Features - 1812 Chip Size, Small surface mountable, Solid state, Faster time to trip than standard SMD devices - Full compliance with EU Directive 2011/65/EU and amending directive 2015/863 - AEC-Q Compliant - Meets Bel automotive qualification* * - Largely based on internal AEC-Q test plan Maximum Voltage Temperature Range 6V -40C to 125C Agency Approval TUV (Std. EN/IEC 60738-1-1 and EN/IEC 60730-1, Cert. R50102117 & R50102187) UL Recognized Component (Std. UL1434, File E305051) LEAD FREE = HALOGEN FREE = AEC-Q Compliant Electrical Characteristics (23 ) Max Time to Trip Resistance Tolerance Agency Approvals Hold Trip Rated Maximum Typical Current Current Voltage Current Power Part Number Current Time Rmin R1max IH, A IT, A Vmax, Vdc Imax, A Pd, W A Sec Ohms Ohms A 0ZTG0110FF2C 1.10 2.20 6 40 1.2 8.0 1.00 0.05 0.43 Y Y IH=Hold current-maximum current at which the device will not trip at 23 still air. IT=Trip current-minimum current at which the device will always trip at 23 still air. VMAX=Maximum voltage device can withstand without damage at it rated current.(I MA X) IMAX= Maximum fault current device can withstand without damage at rated voltage (V MA X). Pd=Typical power dissipated-type amount of power dissipated by the device when in the tripped state in 23 still air environment. RMIN=Minimum device resistance at 23 prior to tripping. R1MAX=Maximum device resistance at 23 measured 1 hour after tripping or reflow soldering of 260 for 20 seconds. Specifications subject to change without notice belfuse.com/circuit-protection 2 / 4 Type 0ZTG 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 165C, 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 165C. 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 125C, 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 2020 Bel Fuse, Inc. Rev. 0ZTG May2020