mc14467-1 rev 5.0, 3/2007 freescale semiconductor technical data ? freescale semiconductor, in c., 2007. all rights reserved. low-power cmos ionization smoke detector ic the mc14467-1, when used with an ionization chamber and a small number of external components, will det ect smoke. when smoke is sensed, an alarm is sounded via an external piezoelectric transducer and internal drivers. this circuit is designed to operate in smoke detector systems that comply with ul217 and ul268 specifications. features ? ionization type with on-chip fet input comparator ? piezoelectric horn driver ? guard outputs on both sides of detect input ? input-production diodes on the detect input ? low-battery trip point, internally set, can be altered via external resistor ? detect threshold, internally set, can be altered via external resistor ? pulse testing for low battery uses led for battery loading ? comparator outputs for detect and low battery ? internal reverse battery protection ? pb-free packaging designated by suffix code ed and eg ordering information device case no. package mc14467p1 648-08 plastic dip mc14467ed1 MCZ14467EG/r2 751g-04 soicw 16 15 14 13 12 11 10 9 1 2 3 4 5 6 7 8 n/c led vdd guard lo-z silver brass vss detect comp. out low v set low v comp. out timing resistor feedback osc capacitor sensitivity set detect input guard hi-z detect comp. out n/c low v set low v comp. out led vdd timing resistor feedback guard hi-z detect inpu t guard lo-z sensitivity set osc capacitor silver brass vss mc14467-1 low-power cmos ionization smoke detector ic p suffix ed suffix (pb-free) 16-lead plastic dip case 648-08 eg suffix (pb-free) 16-lead soicw case 751g-04 9 10 11 12 13 14 15 16 figure 1. pin connections 5 6 7 8 1 2 3 4
sensors 2 freescale semiconductor mc14467-1 figure 2. block diagram table 1. maximum ratings (1) (voltages referenced to v ss ) 1. maximum ratings are those values beyond whic h damage to the device may occur. this devi ce contains circuitry to protect the i nputs against damage due to high static voltages or electric fields; however, it is advised that normal prec autions be taken to avoid application of any voltage higher than maximum rated voltages to this high im pedance circuit. for proper operation it is recommended that exce pt for pin 8, v in and v out be constrained to the range v ss (v in or v out ) v dd . for pin 8, refer to the electrical characteristics. rating symbol value unit dc supply voltage v dd ? 0.5 to + 15 v input voltage, all inputs except pin 8 v in ? 0.25 to v dd + 0.25 v dc current drain per input pin, except pin 15 = 1 ma i 10 ma dc current drain per output pin i 30 ma operating temperature range t a ? 10 to +60 c storage temperature range t stg ? 55 to + 125 c reverse battery time t rb 5.0 s + ? + ? + ? v dd led driver 5 6 9 10 11 8 priezoelectric horn driver 4 v dd v dd v dd low battery comp. latch 80 k v dd 3 7 12 oscillator timer 1045 k 13 1125 k 15 detect input 14 lo-z active guard 1 latch
sensors freescale semiconductor 3 mc14467-1 table 2. recommended operating conditions (voltages referenced to v ss ) parameter symbol value unit supply voltage v dd 9.0 v timing capacitor ? 0.1 f timing resistor ? 8.2 m ? battery load (resistor or led) ? 10 ma table 3. electrical characteristics (voltages referenced to v ss , t a = 25 c) characteristic symbol v dd v dc min typ (1) 1. data labelled ?typ'' is not to be used for design purposes but is intended as an in dication of the ic's potential performance . max unit operating voltage v dd ? 6.0 ? 12 v output voltage piezoelectric horn drivers (i oh = - 16 ma) comparators (i oh = - 30 a) piezoelectric horn drivers (i ol = +16 ma) comparators (i ol = +30 a) v oh v ol 7.2 9.0 7.2 9.0 6.3 8.5 ? ? ? 8.8 ? 0.1 ? ? 0.9 0.5 v v output voltage - led driver, i ol = 10 ma v ol 7.2 ? ? 3.0 v output impedance, active guard pin 14 pin 16 lo-z hi-z 9.0 9.0 ? ? ? ? 10 1000 k ? operating current (r bias = 8.2 m ? ) i dd 9.0 12.0 ? ? 5.0 ? 9.0 12.0 a input current - detect (40% r.h.) i in 9.0 ? ? 1.0 pa internal set voltage low battery sensitivity v low v set 9.0 ? 7.2 47 ? 50 7.8 53 v %v dd hysteresis v hys 9.0 75 100 150 mv offset voltage (measured at vin = vdd/2 active guard detect comparator v os 9.0 9.0 ? ? ? ? 100 50 mv input voltage range, pin 8 v in ? vss - 10 ? vdd + 10 v input capacitance c in ? ? 5.0 ? pf common mode voltage range, pin 15 v cm ? 0.6 ? vdd - 2 v
sensors 4 freescale semiconductor mc14467-1 figure 3. typical led output i-v characteristic figure 4. typical comparator output i-v characteristic figure 5. typical p horn driver output i-v characteristic table 4. timing parameters (c = 0.1 f, r bias = 8.2 m ? , v dd = 9.0 v, t a = 25 c, see figure 7 ) characteristics symbol min typ (1) max units oscillator period no smoke smoke t ci 1.34 32 1.67 40 2.0 48 s ms oscillator rise time t r 8.0 10 12 ms horn output on time (during smoke) off time pw on pw off 120 60 160 80 208 104 ms ms led output between pulses on time t led pw on 32 8.0 40 10 48 12 s ms horn output on time (during low battery) between pulses t on t off 8.0 32 10 40 12 48 ms s 1. data labelled ?typ? is not to be used for design purposes but is intended as an indication of the ic?s potential performance. v ds , drain to source voltage (v dc ) 0 1234 56 7 8910 0.1 1.0 10.0 100.0 v dd = 9.0 v dc i d , drain current (ma) v dd = 7.2 v dc t a = 25c v ds , drain to source voltage (v dc) 012 34 56 78910 0.01 0.1 1.0 10.0 v dd = 9.0 v dc or 7.2 v dc t a = 25c p-ch source and n-ch sink current i d , drain current (ma) 0123456789 1.0 10.0 100.0 1000.0 i d , drain current (ma) 012345678910 1.0 10.0 100.0 1000.0 v ds , drain to source voltage (v dc ) 10 v ds , drain to source voltage (v dc ) i d , drain current (ma) v dd = 9.0 v dc v dd = 7.2 v dc ta = 25c p-ch source current v dd = 9.0 v dc t a = 25c n-ch sink current v dd = 7.2 v dc
sensors freescale semiconductor 5 mc14467-1 device operation timing the internal oscillator of the mc14467-1 operates with a period of 1.67 seconds during no-smoke conditions. each 1.67 seconds, internal power is applied to the entire ic and a check is made for smoke, except during led pulse, low battery alarm chirp, or horn modulation (in smoke). every 24 clock cycles a check is made for low battery by comparing v dd to an internal zener voltage. since very small currents are used in the oscillator, the oscillator capacitor should be of a low leakage type. detect circuitry if smoke is detected, the oscillator period becomes 40 ms and the piezoelectric horn oscillator circuit is enabled. the horn output is modulated 160 ms on, 80 ms off. during the off time, smoke is again checked and will inhibit further horn output if no smoke is sensed. during smoke conditions the low battery alarm is inhibited, but the led pulses at a 1.0 hz rate. an active guard is provided on both pins adjacent to the detect input. the voltage at these pins will be within 100 mv 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. the active guard op amp is not power st robed and thus gives constant protection from surface leakage currents. pin 15 (the detect input) has internal diode prot ection against static damage. sensitivity/low battery thresholds both the sensitivity threshol d and the low battery voltage levels are set internally by a common voltage divider (please see figure 2 ) connected between vdd and vss. these voltages can be altered by exte rnal resistors connected from pins 3 or 13 to either vdd or vss. there wi ll be a slight interaction here due to the common voltage divider network. the sensitivity threshold can also be set by adjusting the smoke chamber ionization source. test mode since the internal op amps and comparators are power strobed, adjustments for sensitiv ity or low battery level could be difficult and/or time-consumin g. by forcing pin 12 to vss, the power strobing is bypassed and the outputs, pins 1 and 4, constantly show smoke/no smoke and good battery/low battery, respectively. pin 1 = vdd for smoke and pin 4 = vdd for low battery. in this mode and during the 10 ms power strobe, chip curr ent rises to approximately 50 a. led pulse the 9-volt battery level is checked every 40 seconds during the led pulse. the battery is loaded via a 10 ma pulse for 10 ms. if the led is not used, it should be replaced with an equivalent resistor su ch that the battery loading remains at 10 ma. hysteresis when smoke is detected, the re sistor/divider network that sets sensitivity is altered to in crease sensitivity. this yields approximately 100 mv of hysteresis and reduces false triggering. figure 6. typical application as ionization smoke detector mc14467-1 1 16 2 3 4 5 6 7 8 15 14 13 12 11 10 9 test + 9.0 v 8.2 m ? 330 ? 1.5 m ? * 220 k ? * 0.1 f 1m 1m 0.1 f 0.001* f *note: component values may change depen ding on type of piezoel ectric horn used.
sensors 6 freescale semiconductor mc14467-1 figure 7. timing diagram smoke/no low battery smoke/low battery no smoke/low battery 10 m s 40 m s 1.67 s oscillator (pin 12) detect out (pin 1) low battery out (pin 4) hysteresis (internal) (pins 13 & 14) sample (internal) smoke (pins 10 & 11) horn (note 1) led (pin 5) (note 3) battery test (note 3) suppressed chirp 24 clock cycles (40 s) 24 clock cycles (0.96 s) 24 clock cycles 6 clock cycles (10.0 s) notes: 1. horn modulation is self-completing. when going from smoke to no smoke, the alarm c ondition will terminat e only when horn is off. 2. comparators are strobed on once per clock cycle (1.67 s for no smoke, 40 ms for smoke). 3. low battery comparator informat ion is latched only during led pulse. 4. ~ 100 mvp?p swing. standby no smoke/ no low battery
sensors freescale semiconductor 7 mc14467-1 package dimensions case 648-08 issue t 16-lead plastic dip
sensors 8 freescale semiconductor mc14467-1 package dimensions case 751g-04 issue f 16-lead soicw
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