DS56 dual temperature comparator DS56 preliminary 071698 1/6 features ? factory calibrated for sensitivity of +6.20 mv/ c and thermometer accuracy of 2.0 c over the 0 c to 85 c range and 3 c over the 40 c to 0 c and +85 c to +125 c range. ? measurement range of 40 c to +125 c ? integrated temperature sensor and voltage reference ? two independent temperature setpoints with respec- tive logic outputs with set hysteresis ? narrowbody so8 (150mil) package ? wide power supply range (2.7v v dd 5.5v) ? functionallycompatible with lm56xim ? applications include monitoring disk drives, printers, office equipment, hvac, appliances, or any power/ cost/temperaturesensitive environments. pin assignment gnd v dd v t1 v t2 v ref t out2 t out1 v temp 1 2 3 4 8 7 6 5 DS56s 8pin soic (150 mil) pin description v ref bandgap voltage reference output v t2 temperature trip point 2 v t1 temperature trip point 1 gnd ground v temp temp sensor output voltage t out2 thermostat output for trip point 2 t out1 thermostat output for trip point 1 v dd power supply voltage (2.7v to 5.5v) description the DS56 has two independent opendrain thermostat outputs and respective trip point inputs. the trippoints are set with external resistors that divide down the 1.25v internal bandgap voltage reference. the voltage resulting from this resistive division is compared with the voltage corresponding to the device's junction tempera- ture to define the thermostat output logic state. the internal temperature sensor has a typical sensitivity of +6.2mv/ c and dc offset of +395 mv at 0 c. both ther- mostat outputs have 5 c of hysteresis. for applications that require temperature measurement as well as control, the temperature sensor voltage is brought out to a pin. the DS56 is packaged in a compact 150 mil 8pin soic. applications include disk drives, printers, office equipment, hvac, appliances, or any power/cost/tem- peraturesensitive environments.
DS56 071698 2/6 detailed pin description table 1 pin symbol type description 1 v ref analog output bandgap output 1.25v (nom) voltage reference output 2 v t2 analog input trip point 2 input associated with thermostat output 2. 3 v t1 analog input trip point 1 input associated with thermostat output 1. 4 gnd gnd ground pin. 5 v temp analog output temperature sensor output. (+6.2 t degc + 395) mv. 6 t out2 digital output (opendrain) thermostat output 2. active low output corresponding to trip point 2. typical hysteresis is 5.0 c. 7 t out1 digital output (opendrain) thermostat output 1. active low output corresponding to trip point 1. typical hysteresis is 5.0 c. 8 v dd v dd supply voltage 2.7v 5.5v input power pin. DS56 functional block diagram figure 1 2.7v 5.5v supply vdd precision reference temperature sensor gnd DS56 100k + + r 3 r 2 r 1 v ref v t2 v t1 t out2 t out1 100k v temp
DS56 071698 3/6 overview a block diagram of the DS56 is shown in figure 1. the DS56 consists of three major components: 1. precision bandgap voltage reference 2. temperature sensor 3. thermostat comparators the DS56 incorporates an internal temperature sensor with a typical transfer function of (in mv with t expressed in c): v temp (t) = 6.2 t + 395 the voltage associated with this transfer function is out- put on the v temp pin, which has a typical output imped- ance of 1.5k w . the DS56 has two independent temperature compara- tors, each with its own input (or trip point) and output. the comparison voltage (the v temp transfer function) is the same for both comparators. additionally, the hyster- esis for both comparators is typically 5 c (31.0 mv). the DS56 bandgap voltage reference is available on pin 1 to allow for a designer to set the trip point(s) by resis- tively dividing the reference voltage. one possible sce- nario is illustrated in figure 1. for optimum perfor- mance, the vref pin should be connected to a 50 m a load. the comparator outputs are taken offchip via open drain fets, thus requiring external pullups. the ther- mostat transfer function is illustrated in figure 2. the supply range of the DS56 is 2.7v to 5.5v, allowing for applications ranging from industrial control to bat- terypowered portable equipment. thermostat output transfer function figure 2 v tx equivalent to 5 c v temp t outx output v tx 31 mv inactive active time
DS56 071698 4/6 absolute maximum ratings* voltage on v dd (gnd0.3v) to +7.0v input current at any pin 5.0 ma package input current 20 ma operating temperature 40 c to +125 c storage temperature 55 c to 150 c esd susceptibility (human body model) 1kv soldering temperature (note 2) 215 c for 60 seconds (vapor phase) 220 c for 15 seconds (ir) * this is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operation sections of this specification is not implied. exposure to absolute maximum rating conditions for extended periods of time may affect reliability. the dallas semiconductor DS56 is built to the highest quality standards and manufactured for long term reliability. all dallas semiconductor devices are made using the same quality materials and manufacturing methods. however, the DS56 is not exposed to environmental stresses, such as burnin, that some industrial applications require. for spe- cific reliability information on this product, please contact the factory in dallas at (972) 3714448. recommended dc operating conditions: (40 c to +125 c; 2.7v v dd 5.5v) parameter symbol condition min typ max units notes supply voltage v dd 2.7 5.5 v 1 dc electrical characteristics: power supply (note 3) (40 c to +125 c; 2.7v v dd 5.5v) parameter symbol condition min typ max units notes supply current i dd 225 m a dc electrical characteristics: temperature sensor (note 3) (40 c to +125 c; 2.7v v dd 5.5v) parameter symbol condition min typ max units notes trip point accuracy tp err 40 c t a 125 c 3 c 4 t r i p p o i n t a ccuracy tp err 0 c t a 85 c 2 c 4 v temp accuracy t err 40 c t a 125 c 3 c 5 v temp a ccuracy t err 0 c t a 85 c 2 c 5 v temp dc offset t=0 c 395 mv sensor gain d v/ d t 6.25 mv/ c trip point hysteresis tp hyst 3.0 5.0 7.0 c power supply 2.7v v dd 3.3v 2.3 mv power supply regulation 3.0v v dd 5.5v 0.3 mv/v v temp output impedance 1500 w
DS56 071698 5/6 dc electrical characteristics: bandgap voltage reference v ref (40 c to +125 c; 2.7v v dd 5.5v) parameter symbol condition min typ max units notes v ref output v ref 1.238 1.25 1.263 v power supply d v ref / 2.7v v dd 3.3v 1.45 mv power supply regulation d v ref / d v dd 30v v dd 5.5v 0.2 mv/v load regulation d v ref / d i l +3.0 m a i l +50 m a 0.15 mv/ m a dc electrical characteristics: trip point inputs v t1 /v t2 (40 c to +125 c; 2.7v v dd 5.5v) parameter symbol condition min typ max units notes input bias current i bias 300 na input range v tin 0 (v dd 1.0) v dc electrical characteristics: thermostat outputs t out1 /t out2 (40 c to +125 c; 2.7v v dd 5.5v) parameter symbol condition min typ max units notes logical a1o output leakage current i out1 v dd = 5.0v 1.0 m a logical a0o output voltage v out0 i out = +50 m a 0.4 v notes: 1. all voltages are referenced to ground, unless otherwise specified. 2. solder according to ipc standards. 3. specified for v temp sourcing 1.0 m a (max) and v ref load current = 50 m a. 4. includes error associated with internal temperature sensor, bandgap voltage v ref , and comparator offset. exter- nal resistance tolerance and temperature coefficient not included in this spec. 5. thermometer error (expressed in c) is the difference between [v o (t) 395]/6.20 and the DS56 case tempera- ture at v dd = 3.0v, thus taking into account sensor error, dc offset error, sensor amplifier gain variations, and amplifier nonlinearity. typical DS56 thermometer error figure 3 tbd typical DS56 v temp transfer function figure 4 tbd
DS56 071698 6/6 DS56 physical dimensions 8, 14, and 16pin soic (.150o body width) ?? ?? ?? pkg 8pin 14pin 16pin dim min max min max min max a in. mm 0.053 1.35 0.069 1.75 0.053 1.35 0.069 1.75 0.053 1.35 0.069 1.75 a1 in. mm 0.004 0.10 0.010 0.25 0.004 0.10 0.010 0.25 0.004 0.10 0.010 0.25 a2 in. mm 0.048 1.24 0.062 1.57 0.048 1.24 0.062 1.57 0.048 1.24 0.062 1.57 b in. mm 0.012 0.030 0.020 0.50 0.012 0.30 0.020 0.50 0.012 0.30 0.020 0.50 c in mm 0.007 0.17 0.011 0.28 0.007 0.17 0.011 0.28 0.007 0.17 0.011 0.28 d in. mm 0.188 4.78 0.196 4.98 0.337 8.55 0.344 8.74 0.386 9.80 0.393 9.98 e in. mm 0.050 bsc 1.27 bsc 0.050 bsc 1.27 bsc 0.050 bsc 1.27 bsc e1 in. mm 0.150 3.81 0.158 4.01 0.150 3.81 0.158 4.01 0.150 3.81 0.158 4.01 h in. mm 0.230 5.84 0.244 6.20 0.230 5.84 0.244 6.20 0.230 5.84 0.244 6.20 l in. mm 0.016 0.40 0.050 0.89 0.016 0.40 0.050 0.89 0.016 0.40 0.050 0.89 q 0 8 0 8 0 8
|
