1/6 2007-07-27 ?A?w??? ionization smoke detector with interconnect smoke detector M75018 general description the M75018 is a low-current cmos circuit providing all of the required features for an ioni zation-type smoke detector. a networking capability allows as many as 40 units to be interconnected so that if any unit senses smoke, all units will sound an alarm. in addition, special features are in corporated to facilitate alignment and test of the finished smoke detector. can be u sed in numerous other battery-operated safety/security applications. features ? piezoelectric horn driver. ? guard outputs on both sides of detect input. ? low-battery trip point, internally set , can be altered via external resistor. ? detect threshold, internally set , ca n be altered via external resistor. ? pulse testing for low-battery uses led for battery loading. ? comparators output for detect. ? strobe output for external trim resistors. ? i/o pin allows up to 40 units to be connected for common signaling. ? power-on reset places ic in standby mode. pin assignment 116 89 det_comp i/o low-v set strobe out led vdd time_res vss feed back horn1 M75018p horn2 osc_cap. sen_set guard 1 dector in guard 2
2/6 2007-07-27 ?A?w??? ionization smoke detector with interconnect smoke detector M75018 pin and circuit description pin no pin name i/o function 1det_comp o this pin provide a method of measuring the detect signal. 2i/o i/o to allow multiple smoke detectors to be command. if any single unit detect smoke (i/o is driven high), all connected units will sound their associated horns. the led is suppressed when an alarm is signaled from an interconnected unit. an internal nmos device acts as a charge dump to aid in applications involving a large (distributed) capacitance on pin 2. the charge dump is activated only on the removal of a local alarm. 3low-v set i the low battery threshold is set internally by a voltage divider connected between vdd and vss. the threshold can be increased by connecting a resistor to vdd. the threshold can be decreased by connecting a resistor to vss. it will be a slight interaction here due the common voltage divider network. the battery voltage level is checked every 40 seconds during the 10ma, battery loading remains at 10 ma.10ms led pulse. 4 strobe out i the detector sensitivity can be decreased by connecting a resistor to pin 13. 5 led o the 9 volt b atter y level is checked ever y 40 seconds durin g the led pulse. the batter y is loaded via a 10ma pulse for 11.6 ms. 6vdd power supply 7time_res. i a resistor between this pin and vdd is part of the oscillator and sets the capacitor charge and discharge current default 8.2m ? . 8 feedback i this pin input to the feedback electrode. if the feedback pin is not used, it must be connected to vdd or vss. 9vss ground 10 horn1 o 11 horn2 o these two pins are used in conjunction with external passive components and a self- resonating piezoelectric transducer. horn1 is connected to the piezo metal support electrode; the complementary output, horn2, is connected to the ceramic electrode. a continuous modulated tone indicates either a local or remote alarm condition. a short (10ms) chirp indicates a low-battery ch irp occurs almost simultaneous with the visible led flash. 12 osc_cap. i a capacitor between this pin and vss is part of the oscillator and sets charge and discharge time (default 0.1 f). 13 sen_set i the detector sensitivity to smoke is set internally by a voltage divider connected between vdd and vss . the sensitivity can be externally adjusted to the individual characteristics of the ionization chamber by connecting a resist or between pin13 and vdd, or between pin 13 and vss. it will be a slight interaction here due the common voltage divider network. 14 guard1 i this will keep surface leakage cu rrents to a minimum and provide a method of measuring the input voltage without loading the ionization chamber. 15 dector in i this pin is the ionization-type smoke detector input. 16 guard2 i the voltage at these pins will be within 100mv of the input signal. this will keep surface leakage currents to a minimum and provide a method of measuring the input voltage without loading the ionization chamber.
3/6 2007-07-27 ?A?w??? ionization smoke detector with interconnect smoke detector M75018 absolute maximum rating parameter sym. rating unit supply voltage range v dd -0.5 ~ 13 v input voltage range v in -0.3 to v dd + 0.3 v input current i in 10 ma operating temperature range t a -10 ~ 60 storage temperature range t s -35 ~ 125 dc electrical characteristics (voltage referenced to vss , ta=25 ) characteristics sym. v dd min. typ. max. unit conditions operating voltage v dd 6.0 12 v 7.2 6.3 v piezoelectric horn drivers (i oh = -16 ma) v oh 9.0 8.5 8.8 v comparators (i oh = -30 a) 7.2 0.9 v piezoelectric horn drivers (i ol = +16 ma) v ol 9.0 0.1 0.5 v comparators (i ol = +30 a) output voltage v ol 7.2 3.0 v led driver (i ol =10 ma) lo-z 9.0 10 k pin 14 output impedance, active guard hi-z 9.0 1000 k pin 16 9.0 5.0 9.0 a operating current i dd 12.0 12.0 a r bias =8.2 m 9.0 1.0 p a detect ( 40% r.h. ) 9.0 0.1 a pin 8 input current i in 6.0 p a@50 , pin 15 v low 9.0 7.2 7.8 v low battery internal set voltage v set 47 50 53 %v dd sensitivity hysteresis v hys 9.0 75 100 150 mv 9.0 100 mv active guard offset voltage (measure at vin=vdd/2) vo s 9.0 50 mv detect comparator input voltage range v in vss-10 v dd +10 v pin 8 input capacitance c in 5.0 pf common mode voltage range v cm 0.6 v dd -2 v pin 15 i ih 25 100 a input , v ih = v dd -2 ( pin 2 ) i/o current i oh -10 -25 ma output , i oh = v dd -2 ( pin 2 ) timing parameters ( c=0.1 f, r bias = 8.2m , v dd = 9.0v , ta=25 ) characteristics sym. min. max unit no smoke 1.46 1.85 s oscillator period smoke t ci 37.5 45.8 ms oscillator rise time t r 10.1 12.3 ms on time pw on 450 550 ms horn output ( during smoke ) off time pw off 450 550 ms between t led 35.0 44.5 s led output pulses on time pw on 10.1 12.3 ms on time t on 10.1 12.3 ms horn output pulses ( during low battery ) off time t off 35.0 44.5 s
4/6 2007-07-27 ?A?w??? ionization smoke detector with interconnect smoke detector M75018 timing diagram notes 1. horn modulation is self-compl eting. when going from smoke to no smoke , the alarm condition will terminate only when horn is off. 2. comparators are strobed on once per clock cycle (1.67s for no smoke , 40 ms for smoke ). 3. low battery comparator information is latched only during led pulse. low battery smoke / no low battery standby no smoke / no low battery osc (pin 12) detect out (pin 1) low battery (internal) hysteresis (internal) (pin 13) (pin 14) i/o (pin2) output (local) smoke no smoke / low battery 40ms 10ms 1.67s horn (pin 10 & 11) led (pin 5) low = disable high = enable (note1) (note3) (note3) suppressed chirp battery test 24 clock cycles strobe out (pin 4) 24 clock cycles (0.96s) 24 clock cycles 6 clock cycles (10.0s) (40s) led (suppressed led for remote only) i/o (pin2) input (remote) low battery chirp
5/6 2007-07-27 ?A?w??? ionization smoke detector with interconnect smoke detector M75018 block diagram 16 15 14 13 8 4 3 2 1 + - + - alarm logic oscillator & timing power-on reset low battery detect comp. out strobe out 11 10 horn 2 horn 1 vdd comparato r i/o feedbac k 40k low-v set 280k 320k sensitivity set detect comparato r + - detect input guard amp guard1 vdd guard2 12 7 gnd 5 led 9 6 osc cap. time res.
6/6 2007-07-27 ?A?w??? ionization smoke detector with interconnect smoke detector M75018 application diagram * all specs and applications shown above subject to change without prior notice. (?H,??) det_comp i/o low-v set strobe out led vdd time_res. vss feed back horn1 M75018p horn2 osc_cap. sen_set guard 1 dector in guard 2 116 89 to othe r units 330 8.2m 1.5m vdd = 9v 0.1uf 0.001uf 220k 0.1uf 1m 1m test
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