general description the max6576/max6577 are low-cost, low-current tem - perature sensors with a single-wire output. the max6576 converts the ambient temperature into a square wave with a period proportional to absolute temperature (k). the max6577 converts the ambient temperature into a square wave with a frequency proportional to absolute tempera - ture. the max6576 offers accuracy of 3c at +25c, 4.5c at +85c, and 5c at +125c. the max6577 offers accuracy of 3c at +25c, 3.5c at +85c, and 4.5c at +125c. both devices feature a single-wire output that minimizes the number of pins necessary to interface with a micropro - cessor. the period/frequency range of the output square wave can be selected by hard-wiring the two time-select pins (ts0, ts1) to either v dd or gnd. the max6576/ max6577 are available in space-saving 6-pin sot23 packages. applications critical p and c temperature monitoring portable battery-powered equipment cell phones battery packs hard drives/tape drives networking and telecom equipment medical equipment features simple single-wire output two output types available ? temperature to period (s) (max6576) ? temperature to frequency (hz) (max6577) 0.8c accuracy at +25c (3c max) no external components operates from +2.7v to +5.5v supply voltage low 140a typical supply current standard operating temperature range: -40c to +125c small 6-pin sot23 package 19-1484; rev 1; 10/14 part temp. range pin- package sot top mark max6576 zut -40c to +125c 6 sot23 aabi max6577 zut -40c to +125c 6 sot23 aabj gnd ts0 n.c. 1 6 out 5 ts1 v dd sot23-6 top view 2 3 4 max6576max6577 +2.7v to +5.5v gnd ts0 ts1 out 0. 1f 0. 1f v dd p gnd i/o v cc max6576max6577 max6576/max6577 sot temperature sensors with period/frequency output pin coniguration typical operating circuit ordering information downloaded from: http:///
terminal voltage (with respect to gnd) v dd .......................................................................-0.3v to +6v ts1, ts0, out.......................................-0.3v to (v dd + 0.3v) input/output current, all pins............................................20ma continuous power dissipation (t a = +70c) 6-pin sot23 (derate 7.10mw/c above +70c)..........571mw operating temperature range...........................-40c to +125c storage temperature range..............................-65c to +150c lead temperature (soldering, 10sec)...............................+300c (v dd = +2.7v to +5.5v, t a = -40c to +125c, unless otherwise noted. typical values are specified at t a = +25c and v dd = +5v, unless otherwise noted.)note 1: see the temperature accuracy histograms in the typical operating characteristics . note 2: the output duty cycle is guaranteed to be 50% by an internal flip-flop. parameter symbol conditions min typ max units v dd range v dd 2.7 5.5 v supply current i dd v dd = 5.5v t a = -40c to +85c 140 250 a t a = -40c to +125c 400 temperature sensor error (note 1) max6576 t a = -20c -7.5 1.1 +7.5 c t a = 0c -5.5 0.9 +5.5 t a = +25c -3.0 0.8 +3.0 t a = +85c -4.5 0.5 +4.5 t a = +125c -5.0 0.5 +5.0 max6577 t a = -20c -7.5 1.1 +7.5 c t a = 0c -6.5 0.9 +6.5 t a = +25c -3.0 0.8 +3.0 t a = +85c -3.5 0.5 +3.5 t a = +125c -4.5 0.5 +4.5 output clock period t out max6576, t (temp) in k, figure 1 v ts1 = gnd, v ts0 = gnd 10t s v ts1 = gnd, v ts0 = v dd 40t v ts1 = v dd , v ts0 = gnd 160t v ts1 = v dd , v ts0 = v dd 640t output clock frequency f out max6577, t (temp) in k, figure 2 v ts1 = gnd, v ts0 = gnd 4t hz v ts1 = gnd, v ts0 = v dd 1t v ts1 = v dd , v ts0 = gnd t/4 v ts1 = v dd , v ts0 = v dd t/16 out duty cycle (note 2) 0.5 time-select pin logic levels v il 0.8 v v ih 2.3 out voltage v ol v dd > 4.5v, i sink = 3.2ma 0.4 v v dd > 2.7v, i sink = 1.2ma 0.3 v oh v dd > 4.5v, i src = 800a v dd - 1.5 v dd > 2.7v, i src = 500a 0.8v dd max6576/max6577 sot temperature sensors with period/frequency output www.maximintegrated.com maxim integrated 2 absolute maximum ratings stresses beyond 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 beyond those indicated in the operational sections of the specifications is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. electrical characteristics downloaded from: http:///
(v dd = +5v, t a = +25c, unless otherwise noted.) 0 2010 30 40 50 60 -5 -3 -2 -4 -1 01234 5 temperature accuracy (t a = +85c) max6576 toc02 accuracy (c) percentage of parts sampled (%) max6576max6577 sample size = 200 100 130120 110 150140 170160 180 -40 -10 5 20 -25 35 50 65 80 95 110 125 supply current vs. temperature max6576/77toc03 temperature (c) supply current (a) max6577 max6576 -1.0 0 -0.5 1.00.5 1.5 -40 -10 5 20 -25 35 50 65 80 95 110 125 accuracy vs. temperature max6575 toc04 temperature (c) accuracy (c) max6576 max6577 +15c/div +100c+25c thermal step response in perfluorinated fluid max6576/77 toc05 5sec/div mounted on 0.75 in. 2 of 2oz. copper 0 10 5 15 20 25 30 35 -5 -3 -2 -4 -1 01234 5 temperature accuracy (t a = +25c) max6576 toc01 accuracy (c) percentage of parts sampled (%) max6576max6577 sample size = 200 +12.5c/div +100c+25c thermal step response in still air max6576/77 toc06 20sec/div mounted on 0.75 in. 2 of 2oz. copper max6576/max6577 sot temperature sensors with period/frequency output maxim integrated 3 www.maximintegrated.com typical operating characteristics downloaded from: http:///
detailed description the max6576/max6577 low-cost, low-current (140a typ) temperature sensors are ideal for interfacing with microcontrollers (cs) or microprocessors (ps). the max6576 converts ambient temperature into a 50% dutycycle square wave with a period proportional to absolute temperature. the max6577 converts ambient temperature into a 50% duty-cycle square wave with a frequency proportional to absolute temperature. time- select pins (ts1, ts0) permit the internal temperature- controlled oscillator (tco) to be scaled by four preset multipliers. the max6576/max6577 feature a single-wire interface to minimize the number of port pins necessary for interfacing with a p. max6576 characteristics the max6576 temperature sensor converts temperature to period. the output of the device is a free-running, 50% duty-cycle square wave with a period that is proportional to the absolute temperature (k) of the device (figure 1). the max6576 has a push/pull cmos output with sharp edges. the speed of the output square wave can be selected by hard-wiring ts1 and ts0 as shown in table 1. one of four scaled output periods can be selected using ts1 and ts0. max6577 characteristics the max6577 temperature sensor converts temperature to frequency. the output of the device is a free-running, 50% duty-cycle square wave with a frequency that is pro - portional to the absolute temperature (k) of the device (figure 2). the max6577 has a push/pull cmos output with sharp edges. the speed of the output square wave can be selected by hard-wiring ts1 and ts0 as shown in table 2. one of four scaled output frequencies can be selected using ts1 and ts0. table 1. max6576 time-select pin configuration table 2. max6577 time-select pin configuration pin name function 1 v dd positive supply voltage 2 gnd ground 3 n.c. no connection. connect pin to gnd or leave open. 4, 5 ts1, ts0 time-select pins. ts1 and ts0 set the temperature scale factor by connecting ts1 and ts0 to either v dd or gnd. see tables 1 and 2. 6 out square-wave output with a clock period proportional to absolute temperature (k) (max6576) square-wave output with a clock frequency proportional to absolute temperature (k) (max6577) ts1 ts0 scalar multiplier (s/k) gnd gnd 10 gnd v dd 40 v dd gnd 160 v dd v dd 640 ts1 ts0 scalar multiplier (hz/k) gnd gnd 4 gnd v dd 1 v dd gnd 1/4 v dd v dd 1/16 note: the temperature, in c, may be calculated as follows: period(s) t( c) 273.15 k scalar multiplier(s/ k) = ? frequency(s) t( c) 273.15 k scalar multiplier(s/ k) = ? note: the temperature, in c, may be calculated as follows: max6576/max6577 sot temperature sensors with period/frequency output www.maximintegrated.com maxim integrated 4 pin description downloaded from: http:///
applications information quick-look circuits figure 3 shows a quick-look application circuit for the max6576 using a universal counter measuring period. ts1 and ts0 are both tied to ground to select a scalar multiplier of 10s/k. the max6576 converts the ambi - ent temperature into a square wave with a period that is 10 times the absolute temperature of the device in s. at room temperature, the universal counter will display approximately 2980s. figure 4 shows a quick-look application circuit for the max6577 using a universal counter measuring frequency. ts1 is tied to ground and ts0 is tied to v dd to select a scalar multiplier of 1hz/k. the max6577 converts the ambient temperature into a square wave with a frequency that is equal to the absolute temperature of the device in hertz. at room temperature, the universal counter will display approximately 298hz. interfacing with a microcontroller figure 5 shows the max6577 interfaced with an 8051 c. in this example, ts1 is tied to ground and ts0 is tied to v dd to select a scalar multiplier of 1hz/k. the max6577 converts the ambient temperature into a square wave with a frequency that is equal to the absolute temperature of the device in hertz. the 8051 c reads the frequency of the square-wave output of the max6577 into timer 0 and displays the temperature as degrees celsius in binary on port 1. listing 1 provides the code for this application. the interface is similar for the max6576, except the c will perform a period measurement. noise considerations the accuracy of the max6576/max6577 is susceptible to noise generated both internally and externally. the effects of external noise can be minimized by placing a 0.1f ceramic bypass capacitor close to the supply pin of the devices. internal noise is inherent in the operation of the devices and is detailed in table 3. internal averaging mini - mizes the effect of this noise when using longer scalar timeout multipliers. the effects of this noise are included in the overall accuracy of the devices as specified in the electrical characteristics . figure 1. max6576 timing diagram figure 2. max6577 timing diagram t out max6576 clock waveform output t out max6577 clock waveform output f out = 1 / t out f out (k) max6576/max6577 sot temperature sensors with period/frequency output www.maximintegrated.com maxim integrated 5 downloaded from: http:///
figure 3. max6576 quick-look circuitfigure 4. max6577 quick-look circuit figure 5. interfacing with a c table 3. typical peak noise amplitude parameter max6576 max6577 scalar multiplier 10 40 160 640 4 1 1/4 1/16 noise amplitude (c) 0.38 0.17 0.11 0.094 0.13 0.066 0.040 0.028 gnd ts0ts1 out 0. 1f v dd +2.7v to +5.5v universal counter "period" max6576 gnd ts0ts1 out 0. 1f v dd +2.7v to +5.5v universal counter "frequency" max6577 gnd ts0ts1 out 0. 1f v dd +2.7v to +5.5v gnd x2 x1 t0 470? x 8 v cc p1.1 p1.0p1.2 p1.3 p1.4 p1.5 p1.6 p1.7 8051 12mhz 22pf22pf max6577 max6576/max6577 sot temperature sensors with period/frequency output www.maximintegrated.com maxim integrated 6 chip information transistor count: 302 downloaded from: http:///
max6576/max6577 sot temperature sensors with period/frequency output www.maximintegrated.com maxim integrated 7 listing 1. 8051 code example downloaded from: http:///
package type package code outline no. land pattern no. 6 sot23 u6-4 21-0058 90-0175 max6576/max6577 sot temperature sensors with period/frequency output www.maximintegrated.com maxim integrated 8 listing 1. 8051 code example (continued) package information for the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages . note that a +, #, or - in the package code indicates rohs status only. package drawings may show a different su ffix character, but the drawing pertains to the package regardless of rohs status. downloaded from: http:///
revision number revision date description pages changed 0 4/99 initial release 1 10/14 removed automotive reference from data sheet 1 maxim integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim integrated product. no circuit patent licenses are implied. maxim integrated reserves the right to change the circuitry and speciications without n otice at any time. the parametric values (min and max limits) shown in the electrical characteristics table are guaranteed. other parametric values quoted in this data sheet are provided for guidance. maxim integrated and the maxim integrated logo are trademarks of maxim integrated products, inc. max6576/max6577 sot temperature sensors with period/frequency output ? 2014 maxim integrated products, inc. 9 revision history for pricing, delivery, and ordering information, please contact maxim direct at 1-888-629-4642, or visit maxim integrateds website at www.maximintegrated.com. downloaded from: http:///
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