general description the MAX6612 is a low-power precision analog output temperature sensor in a tiny 5-pin sc70 package. the sensitivity of the output voltage to temperature is a high 19.53mv/?. this sensitivity provides superior noise immunity. the voltage/temperature slope is chosen to provide convenient bit weights when the MAX6612 dri- ves the input of an adc with a 2.5v or 5v reference. the MAX6612 provides an analog voltage output propor- tional to temperature. accuracy is ?.2? (max) at +25?, ?.0 (max) from t a = 0? to +70?, and ?.5? (max) from t a = -10? to +125?. useful measurements can be obtained at temperatures as high as +150?. self-heating effects are negligible due to the low current consumption of the part. unlike many analog temperature sensors, the MAX6612 is stable with large capacitive loads. any capacitive load greater than or equal to 1000pf yields stable oper- ation, providing broad flexibility in board-level design. the operating temperature range varies with the supply voltage, with a higher supply voltage enabling a wider temperature range. the MAX6612 can be used over a range of -10? to +125? with a supply voltage of 3.3v or greater. for applications with a supply voltage of 2.4v, the MAX6612 can be used over a temperature range of -10? to +70?. applications base stations industrial equipment home appliances battery packs medical instruments portable equipment gps equipment features optimized for use with adcs high temperature-to-voltage slope able to drive high-capacitive loads operates up to +150? low current consumption (35? max) no calibration required space-saving sc70 package MAX6612 high-slope, low-power, analog temperature sensor in an sc70 package ________________________________________________________________ maxim integrated products 1 ordering information MAX6612 max1137 v cc v supply v dd gnd gnd out ain_ c s c load c ref sda scl r pu1 r pu2 typical application circuit 19-2546; rev 0; 7/02 for pricing, delivery, and ordering information, please contact maxim/dallas direct! at 1-888-629-4642, or visit maxim? website at www.maxim-ic.com. part temp range pin- package top mark MAX6612mxk-t -55 c to +150 c 5 sc70-5 adg gnd v cc out 15 b a MAX6612 sc70 top view 2 34 pin configuration
output voltage vs. ambient temperature MAX6612 toc01 ambient temperature ( c) output voltage (mv) 125 100 75 50 25 0 500 1000 1500 2000 2500 3000 3500 0 -25 150 v cc = 5.5v supply current vs. supply voltage MAX6612 toc02 supply voltage (v) supply current ( a) 5 4 3 2 5 10 15 20 25 0 16 t a = +25 c typical operating characteristics (v cc = 3.3v, c s = 0.1f, c load = 1000pf, unless otherwise specified.) MAX6612 high-slope, low-power, analog temperature sensor in an sc70 package 2 _______________________________________________________________________________________ absolute maximum ratings electrical characteristics (v cc = 2.4v to 5.5v, c load = 1000pf, t a = -10 c to +150 c, unless otherwise specified.) stresses beyond those listed under ?bsolute maximum ratings?may cause permanent damage to the device. these are stress rating s only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specificatio ns is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. note 1: 100% production tested at +25 c. guaranteed by design through temperature. note 2: t is in c. note 3: guaranteed by design. v cc to gnd ..............................................................-0.3v to +6v out to gnd..................................................-0.3v to v cc + 0.3v esd protection (human body)...........................................2000v current into any pin ............................................................20ma output short-circuit duration.....................................continuous continuous power dissipation (t a = +70 c) 5-pin sc70 (derate 3.1mw/ c above +70 c) ..............245mw operating temperature range .........................-55 c to +150 c junction temperature ......................................................+150 c storage temperature range .............................-65 c to +165 c lead temperature (soldering, 10s) .................................+300 c parameter symbol conditions min typ max units t a = +25 c, v cc = 3.3v -1.2 +1.2 t a = +60 c to +70 c, v cc = 3.3v -3.0 +3.0 t a = +60 c to +100 c, v cc = 3.3v -4.3 +4.3 t a = -10 c to +125 c, v cc = 3.3v -5.5 +5.5 temperature error v out = 0.4 + (0.01953 ? t) (2 ? 10 -6 ? t 2 ) (notes 1, 2) t a = -10 c to +150 c, v cc = 5.5v 5 c supply voltage range v cc 2.4 2.3 5.5 v supply current i q no load 35 a output voltage v out t a = 0 c 400 mv sensor gain (average slope) t a = -10 c to +150 c 19.53 mv/ c capacitive load no sustained oscillations (note 3) 1000 pf turn-on time c load = 1000pf 80 s shutdown current v cc < 0.8v 1 a supply sensitivity v cc = 2.4v to 5.5v 0.5 0.8 c/v load regulation i out = 2a to 100a 0.03 c/a
detailed description the MAX6612 is an analog output temperature sensor whose output voltage is a linear function of its die tem- perature. the slope of the output voltage is 19.53mv/ c and there is a 400mv offset at 0 c to allow measure- ment of negative temperatures. the maximum supply current is 35a, and the supply voltage range is from 2.4v to 5.5v for the -10 c to +150 c temperature range. the temperature error is less than 1.2 c at t a = +25 c, 3 c from t a = 0 c to +70 c, and 4.5 c from t a = -10 c to +125 c. the operating temperature range varies with the supply voltage with higher supply voltages enabling wider temperature ranges. the MAX6612 can be used over a range of -10 c to +125 c with a supply voltage of 3.3v or greater. for applications with a supply voltage of 2.4v, the MAX6612 can be used over a temperature range of -10 c to +70 c. transfer function the temperature-to-voltage transfer function has a lin- ear positive slope and can be approximated by the equation: v out = 0.40v + (0.01953v/ c ? t c) - (2 ? 10 -6 ? t c 2 ) where t is the MAX6612 s die temperature in c. therefore: t ( c) = (v out - 0.40v) / 0.01953v/ c applications information sensing circuit board and ambient temperatures temperature sensor ics like the MAX6612 that sense their own die temperatures must be mounted on or close to the object whose temperature they are intend- ed to measure. because there is a good thermal path between the sc70 package s metal leads and the ic die, the MAX6612 can accurately measure the temper- ature of the circuit board to which it is soldered. if the sensor is intended to measure the temperature of a heat-generating component on the circuit board, it should be mounted as close as possible to that compo- nent and should share supply and ground traces (if they are not noisy) with that component where possible. this maximizes the heat transfer from the component to the sensor. MAX6612 high-slope, low-power, analog temperature sensor in an sc70 package typical operating characteristics (continued) (v cc = 3.3v, c s = 0.1f, c load = 1000pf, unless otherwise specified.) supply current vs. ambient temperature MAX6612 toc03 ambient temperature ( c) supply current ( a) 125 100 75 50 25 0 -25 -50 5 10 15 20 25 30 35 0 -75 150 v cc = 5.5v v cc = 3.3v v cc = 2.4v step response from +25 c to +100 c in flourinert bath MAX6612 toc04 1s/div v out 500mv/div 0 pin name function 1 a must be connected to gnd. 2 gnd gnd 3 out temperature sensor output. connect a capacitor (at least 1000pf) from this pin to gnd. 4v cc power-supply input. bypass v cc to gnd with a 0.1f ceramic capacitor. 5 b must be connected to gnd. pin description _______________________________________________________________________________________ 3
MAX6612 the thermal path between the plastic package and the die is not as good as the path through the leads, so the MAX6612, like all temperature sensors in plastic pack- ages, is less sensitive to the temperature of the sur- rounding air than it is to the temperature of its leads. it can be successfully used to sense ambient tempera- ture if the circuit board is designed to track the ambient temperature. as with any ic, the wiring and circuits must be kept insulated and dry to avoid leakage and corrosion, especially if the part is operated at cold temperatures where condensation can occur. the MAX6612 is a very low-power temperature sensor and is intended to drive very light loads. as a result, the temperature rise due to power dissipation on the die is insignificant under normal conditions. for example, with the MAX6612 operating from a 3v supply at +25 c (v out = 0.888v), driving a 100k ? load (i out = 10a), and in the 5-pin sc70 package, the die temperature increases above the ambient by 0.036 c. therefore, the error caused by power dissipation is negligible. driving adc inputs the MAX6612 s temperature-to-voltage transfer func- tion provides convenient lsb weights when driving adcs with 2.5v or 5v references. with a 5v reference, an 8-bit adc has an lsb value equal to 19.53mv, which corresponds exactly to the voltage produced by a 1 c change in the MAX6612 s temperature. an 8-bit adc with a 2.5v reference has an lsb value of 9.765mv, or 0.5 c. capacitive loads the MAX6612 is optimized for stability with large capacitive loads such as noise-filtering capacitors at the input of an adc. for stable operation, ensure that the MAX6612 has a load capacitance of at least 1000pf located near its output pin. chip information transistor count: 257 process: bicmos high-slope, low-power, analog temperature sensor in an sc70 package 4 _______________________________________________________________________________________
MAX6612 high-slope, low-power, analog temperature sensor in an sc70 package maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim product. no circu it patent licenses are implied. maxim reserves the right to change the circuitry and specifications without notice at any time. maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 _____________________ 5 ? 2002 maxim integrated products printed usa is a registered trademark of maxim integrated products. package information (the package drawing(s) in this data sheet may not reflect the most current specifications. for the latest package outline info rmation, go to www.maxim-ic.com/packages .) sc70, 5l.eps
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