2-29 telcom semiconductor, inc. 7 6 5 4 3 1 2 8 tc626* temperature limit switch features n requires no external components n on-chip temperature sensing n to-220 package for "hot spot" mounting n 50ma output signal to-220 package (tc626vab) n to-92 package for direct circuit board mounting applications n vibration-immune temperature sensing n fan speed control circuits n system overtemperature shutdown n advanced thermal warning n consumer products general description the tc626 is a temperature limit detector that notifies the system when measured temperature is above the fac- tory-programmed setting. it is designed to replace mechani- cal (bimetal) temperature limit switches and offers increased ruggedness, higher reliability and greater setpoint accuracy. it requires no external components. the tc626 operates over a C 55 c to +125 c tempera- ture range. it is available in a to-92 package, which is ideal for ambient temperature sensing applications. it is also available in a to-220-3 package for heatsink temperature measurement applications. ordering information temperature part number* package range tc626040vab to-220-3 C 55 c to +125 c TC626040VZB to-92-3 C 55 c to +125 c tc626050vab to-220-3 C 55 c to +125 c tc626050vzb to-92-3 C 55 c to +125 c tc626080vab to-220-3 C 55 c to +125 c tc626080vzb to-92-3 C 55 c to +125 c tc626090vab to-220-3 C 55 c to +125 c tc626090vzb to-92-3 C 55 c to +125 c tc626100vab to-220-3 C 55 c to +125 c tc626100vzb to-92-3 C 55 c to +125 c *trip-point temperature is designated as follows: part numbers are tc626xxxvab or tc626vzb, where xxx = trip-point tempeature in c. for high volume applications requiring different trip-points, contact factory. 2 5v to 18v relay 1 3 nc system power nc = normally closed pin 1 switches 'high' if temperature goes above the preset value. tc626 pin configurations * patented tc626-6 8/23/96 tc626xxxvzb 123 123 123 tc626xxxvab output ground v dd output ground v dd to-220-3 to-92-3 system overtemperature protection
2-30 telcom semiconductor, inc. preliminary information electrical characteristics: v dd = +5v and t a = C 55 c to +125 c, unless otherwise specified. parameter test conditions min typ max units supply voltage 4.5 18 v supply current 300 600 m a output resistance output high or low 75 w output current source/sink, v cc = 18v 25 ma source/sink, v cc = 4.5v 10 ma absolute accuracy at trip point t C 3 t t + 3 c trip point hysteresis 3.5 5 6.5 c telcom semiconductor reserves the right to make changes in the circuitry or specifications detailed in this manual at any time without notice. minimums and maximums are guaranteed. all other specifications are intended as guidelines only. telcom semiconductor assumes no responsi bility for the use of any circuits described herein and makes no representations that they are free from patent infringement. detailed description the tc626 output maintains a logic low state when measured temperature is below the factory-programmed setting. as temperature rises, the output is driven active to a high level [v dd C (i out )(r out )] when temperature equals the setpoint value 3 c. built-in hysteresis prevents output "chattering" when measured temperature is at (or near) the trip point (figure 1). as temperature falls through the trip point, hysteresis main- tains the output high until measured temperature is 5 c lower than the trip point setting. the tc626vzb (to-92 package) has a maximum out- put current of 10ma while the tc626vab has a maximum output current of 50ma. care must be taken to observe these output current limits as output currents in excess of those stated will cause device self-heating resulting in erroneous temperature measurements. absolute maximum ratings* package power dissipation (t a 70 c) to-92 ...........................................................440mw to-220 ............................................................1.6mw supply voltage ............................................................20v input voltage any input ...... (gnd C 0.3v) to (v dd + 0.3v) operating temperature ......................... C 55 c to +125 c maximum junction temperature ........................... +150 c storage temperature ............................ C 65 c to +150 c lead temperature (soldering, 10 sec) ................. +300 c *stresses above those listed under "absolute maximum ratings" may cause permanent damage to the device. these are stress ratings only and functional operation of the device at these or any other conditions above those indicated in the operation sections of the specifications is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. set point (set point ?5 c) output figure 1. tc626 operation temperature limit switch tc626
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