note: for detailed information on purchasing options, contact your local allegro field applications engineer or sales representative. allegro microsystems, inc. reserves the right to make, from time to time, revisions to the anticipated product life cycle plan for a product to accommodate changes in production capabilities, alternative product availabilities, or market demand. the information included herein is believed to be accurate and reliable. however, allegro microsystems, inc. assumes no respon- sibility for its use; nor for any infringements of patents or other rights of third parties which may result from its use. recommended substitutions: ionization smoke detector with interconnect A5350 date of status change: november 2, 2009 these parts are no longer in production the device should not be purchased for new design applications. samples are no longer available. discontinued product
description the A5350 is a low-current, bicmos circuit providing all of the required features for an ionization-type smoke detector. a networking capability allows as many as 125 units to be interconnected so that if any unit senses smoke all units will sound their alarm. in addition, special features are incorporated to facilitate alignment and test of the finished smoke detector. the internal oscillator and timing circuitry keep standby power to a minimum by powering down the device for 1.66 seconds and sensing for smoke for only 10 ms. every 24 on-off cycles, a check is made for a low battery condition. by substituting other types of sensors or a switch for the ionization detector, this very-low?power device can be used in numerous other battery-operated safety/security applications. the A5350 is supplied in a low-cost 16-pin dual in-line plastic package (dip). it is rated for continuous operation over the temperature range of ?10c to 60c. the pb (lead) free version (suffix ?t) has 100% matte tin leadframe plating. 26110.5 rev. 5 features and benefits ? low average standby current for long battery life ? interconnect up to 125 detectors ? piezoelectric horn driver ? guard outputs for detector input ? pulse testing for low battery ? power-on reset (por) ? internal reverse battery protection ? inverted alarm polarity on detect in ionization smoke detector with interconnect typical application A5350 A5350 nc i/o low-v set nc led vdd timing res feedback guard2 detect in guard1 sensitivity set osc cap horn2 horn1 vss to / from other units 9 10 11 12 13 14 15 16 200 k 200 8.2 m 1 f 0.1 f 1.5 m 4.7 m 200 k 220 k push to test 0.001 f 330 9 v b c c c a b use an external resistor divider to set sensitivity for a particular smoke chamber. c a resistor to vss or vdd may be added to this pin to modify low battery voltage threshold. value of component will vary, based on the piezoelectric horn used. 1 2 3 4 5 6 7 8 4.7 m a package: 16-pin dip (suffix a): not to scale
ionization smoke detector with interconnect A5350 2 allegro microsystems, inc. 115 northeast cutoff worcester, massachusetts 01615-0036 u.s.a. 1.508.853.5000; www.allegromicro.com characteristic symbol test conditions* value units package thermal resistance r ja 4-layer pcb based on jedec standard 38 oc/w *additional thermal information available on allegro website. number name function 1 nc no connection 2 i/o input/output to interconnected detectors 3 low-v set optionally used with a resistor to adjust low-battery threshold 4 nc no connection 5 led output to drive visible led 6 vdd positive supply voltage 7 timing res terminal for timing resistor, sets internal bias (affects timing) 8 feedback input for driving piezoelectric horn 9 vss negative supply voltage 10 horn1 output for driving piezoelectric horn 11 horn2 complementary output for driving piezoelectric horn 12 osc cap terminal for charging/discharging an external capacitor to run the oscillator 13 sensitivity set used with a resistor divider to externally set sensitivity for a specific chamber 14 guard1 active guard 1 for detector input 15 detect in input from detector chamber 16 guard2 active guard 2 for detector input 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 nc i/o low-v set nc led vdd timing res feedback guard2 detect in guard1 sensitivity set osc cap horn2 horn1 vss selection guide part number pb-free packing A5350ca-t* yes 25 pieces per tube A5350ca ? *variant is in production but has been determined to be not for new design. this classifi- cation indicates that sale of the variant is currently restricted to existing customer applications. the variant should not be purchased for new design applications because obsolescence in the near future is probable. samples are no longer available. status change: may 4, 2009. absolute maximum ratings* characteristic symbol notes rating units supply voltage range v dd referenced to v ss ?0.5 to 15 v input voltage range v in referenced to v ss ?0.3 to v dd + 0.3 v reverse battery condition duration t rbat 10.5 v 20 s input current i in 10 ma operating ambient temperature t a ?10 to 60 oc junction temperature t j (max) 150 oc storage temperature range t stg ?55 to 125 oc * caution:bicmos devices have input static protection but are susceptible to damage when exposed to extremely high static elect rical charges. terminal list table pin-out diagram thermal characteristics
ionization smoke detector with interconnect A5350 3 allegro microsystems, inc. 115 northeast cutoff worcester, massachusetts 01615-0036 u.s.a. 1.508.853.5000; www.allegromicro.com functional block diagram low battery 9v logic oscillator and timing power-on reset + v dd + v dd v dd vdd i/o feedback horn1 horn2 led timing res osc cap guard2 guard1 sensitivity set low-v set +supply + _ + _ + _ vss -supply + v dd 600 k 500 k 1.1 m smoke comparator comparator ion chamber band gap low battery sample smoke sample lbsamp lbsamp ssamp ssamp detect in
ionization smoke detector with interconnect A5350 4 allegro microsystems, inc. 115 northeast cutoff worcester, massachusetts 01615-0036 u.s.a. 1.508.853.5000; www.allegromicro.com electrical characteristics 1,2 at t a = 25c, v dd = 9.0 v, v ss = 0 v, c osccap = 0.1 f, r timingres = 8.2 m (unless otherwise noted) continued on the next page? characteristic symbol test conditions test pin min. typ. max. units supply voltage range v dd operating 6 6.0 9.0 12 v supply current i dd v dd = 9.0 v, no alarm, no loads 6 ? 5.0 9.0 a v dd = 12 v, no alarm, no loads 6 ? ? 12 a detector input current i detectin 0% to 40% rh, v in = 0 to 9.0 v 15 ? ? 1.0 pa input offset voltage v os(guard1) active guard1 14, 15 ? ? 100 mv v os(guard2) active guard2 16, 15 ? ? 100 mv v os detect comparator 15, 13 ? ? 50 mv common mode range v cm(guard) guard ampli er 14, 15 2.0 ? v dd ? 0.5 v v cm smoke comparator 13, 15 0.5 ? v dd ? 2.0 v active guard impedance z ag1 guard1 to vss 14 ? 10 ? k z ag2 guard2 to vss 16 ? 500 ? k oscillator period t osc no alarm 12 1.34 1.67 2.00 s t osc(alarm) local or remote alarm 12 37.50 41.67 45.84 ms oscillator pulse width t w(osc) 12 8.0 10 12 ms low-battery threshold v dd(th) t a = 0c to 50c, low-v set open circuit 6 7.2 ? 7.8 v horn output voltage v ol i out = 16 ma, v dd = 9.0 v 10, 11 ? 0.1 0.5 v i out = 16 ma, v dd = 7.2 v 10, 11 ? ? 0.9 v v oh i out = ?16 ma, v dd = 9.0 v 10, 11 8.5 8.8 ? v i out = ?16 ma, v dd = 7.2 v 10, 11 6.3 ? ? v horn output on-time t on(horn) local or remote alarm 10,11 120 160 208 ms t w(horn) low battery 10, 11 8.0 10 12 ms horn output off-time t off(horn) local or remote alarm 10, 11 60 80 104 ms t horn low battery 10, 11 32 40 48 s led output-on current i led v dd = 7.2 v, v led = 1.0 v 5 10 ? ? ma led output on-time t w(led) 5 8.0 10 12 ms led output off-time t led1 no alarm, in standby 5 32 40 48 s t led3 local alarm or test alarm 5 0.76 0.97 1.14 s t led4 remote alarm, no local smoke 5 ? no led pulses ?s
ionization smoke detector with interconnect A5350 5 allegro microsystems, inc. 115 northeast cutoff worcester, massachusetts 01615-0036 u.s.a. 1.508.853.5000; www.allegromicro.com the A5350 is a low-current, bicmos circuit providing all of the required features for an ionization-type smoke detector. the alarm polarity on detect in is inverted as compared with typi- cal ion-type devices. the detect in voltage must rise above the sensitivity set voltage in order to cause an alarm. oscillator an internal oscillator operates with a period of 1.67 seconds during no-smoke conditions. every 1.67 seconds, internal power is applied to the entire circuit for 10 ms and a check is made for smoke. every 24 clock cycles (approximately 40 seconds), the led pin is pulsed and a check is made for low battery by com- paring v dd to an internal reference. because very-low currents are used in the device, the oscillator capacitor at the osc cap pin should be a low-leakage type (ptfe, polystyrene, or polypro- pylene). detector circuitry when the voltage on the detect in pin is greater than the volt- age on the sensitivity set pin, the A5350 evaluates this as a smoke condition . an active guard is provided on guard1 and guard2, the two pins adjacent to the detector input, the detect in pin. v guard1 and v guard2 will be within 100 mv of v detectin . this will keep surface leakage currents to a minimum and provide a method of measuring the input voltage without loading the ion- ization chamber. the active guard amplifier is not power strobed and thus provides constant protection from surface leakage currents. the detector input has internal diode protection against electrostatic damage. alarm circuitry if smoke is detected, the oscillator period changes to 40 ms and the horn is enabled. the horn output is typically 160 ms on, 80 ms off. during the off-time, smoke is checked and further alarm output will be inhibited if smoke is not sensed. during a smoke condition, the low-battery alarm is inhibited and the led is pulsed approximately once every second. sensitivity adjust the detector sensitivity must be externally set to the individual characteristics of the ionization chamber by connecting the circuit description characteristic symbol test conditions test pin min. typ. max. units i/o current i iol no alarm, v i/o = v dd ? 2.0 v 2 25 ? 60 a i ioh local alarm, v i/o = v dd ? 2.0 v 2 ?7.5 ? ? ma i/o alarm voltage v ih(io) external ?alarm? in 2 3.0 ? ? v i/o delay t r(io) local or test alarm to i/o active 2 ? 3.0 ? s 1 negative current is de ned as coming out of the speci ed device pin (sourcing). 2 alarm (smoke) condition is de ned as v detectin > v sensitivityset ; no alarm (no smoke) condition is de ned as v detectin < v sensitivityset . electrical characteristics 1,2 (continued) at t a = 25c, v dd = 9.0 v, v ss = 0 v, c osccap = 0.1 f, r timingres = 8.2 m (unless otherwise noted)
ionization smoke detector with interconnect A5350 6 allegro microsystems, inc. 115 northeast cutoff worcester, massachusetts 01615-0036 u.s.a. 1.508.853.5000; www.allegromicro.com sensitivity set pin to a resistor divider connected between the vdd and vss pins. low battery the low battery condition threshold is set internally by a voltage divider connected between vdd and vss. the threshold can be externally adjusted by connecting a resistor between the low-v set pin and either the vdd or vss pins. to increase the threshold, a resistor can be connected between low-v set and vss. given an initial threshold, v (th)init (nomi- nally 7.5 v), and a target threshold, v (th)set , the resistor should have the value: r lowvset = 600e3 k / (1 ? 0.375 k ) , where k = 1 / ( v (th)set / [0.727 v (th)init ] ? 1) . to decrease the threshold, a resistor can be connected between low-v set and vdd. given an initial threshold, v (th)init (nomi- nally 7.5 v), and a target threshold, v (th)set , the resistor should have the value: r lowvset = 960e3 k / (0.6 ? 1.6 k ) , where k = v (th)set / (0.727 v (th)init ) ? 1 . the battery voltage level is checked approximately every 40 sec- onds during the (approximately) 10 ma, 10 ms led pulse. if an led is not used, it should be replaced with an equivalent resistor (typically 500 to 1000 ) such that the battery loading remains about 10 ma. i/o a connection to the i/o pin allows multiple smoke detectors to be interconnected. if any single unit detects smoke, its i/o pin is driven high (after a nominal 3 s delay), and all connected units will sound their associated horns. when the i/o pin is driven high by another device, the oscillator immediately speeds up to its 41.7 ms period. the remainder of the sped-up clock cycle, and two additional consecutive clock cycles with i/o high are required to cause an alarm. if the i/o pin falls below its threshold at any time during those (approximately) 83.4 ms, an internal latch is reset and there will not be an alarm. thus, the i/o must remain high for (approximately) 93.9 ms in order to cause an alarm. this filtering provides significant immunity to i/o noise. the led is suppressed when an alarm is signaled from an interconnected unit, and any local alarm condition causes the i/o pin to be ignored as an input. this pin has an on-chip pulldown device and must be left unconnected if not used. testing on power-up, all internal counters are reset. internal test cir- cuitry allows low battery check by holding the feedback and osc cap pins low during power-up, then reducing v dd and monitoring the horn1 pin. horn1 will be driven high when v dd falls below the low-battery threshold. all functional tests can be accelerated by driving the osc cap pin with a 2 khz square wave. the 10 ms strobe period must be maintained for proper operation of the comparator circuitry.
ionization smoke detector with interconnect A5350 7 allegro microsystems, inc. 115 northeast cutoff worcester, massachusetts 01615-0036 u.s.a. 1.508.853.5000; www.allegromicro.com timing diagrams (not to scale) osc cap pin internal clock led pin smoke sample standby mode low battery test t osc t w( osc) t led1 led on t w( led) test event vdd pin led pin horn enable low battery condition (low battery) t led1 t w(led) led off (high-z) t w( horn) t horn led on led off (high-z) low battery test
ionization smoke detector with interconnect A5350 8 allegro microsystems, inc. 115 northeast cutoff worcester, massachusetts 01615-0036 u.s.a. 1.508.853.5000; www.allegromicro.com osc cap pin internal clock led pin smoke sample horn enable t osc(alarm) 6 clock cycles local smoke detection/test alarm condition i/o pin t r(io) (output) t w(osc) t on(horn) t off(horn) t led3 t w(led) led pin led off (high-z) led on v detectin > v sen sitivityset (smoke) (no smoke ) smoke chamber smoke sample horn enable i/o pin remote alarm condition (input) led pin t on(horn) t off(horn) osc cap pin internal clock t osc(alarm) t w( osc) i/o pin test event led off (high-z)
ionization smoke detector with interconnect A5350 9 allegro microsystems, inc. 115 northeast cutoff worcester, massachusetts 01615-0036 u.s.a. 1.508.853.5000; www.allegromicro.com copyright ?1995-2009, allegro microsystems, inc. the products described here are manufactured under one or more u.s. patents or u.s. patents pending. allegro microsystems, inc. reserves the right to make, from time to time, such de par tures from the detail spec i fi ca tions as may be required to per- mit improvements in the per for mance, reliability, or manufacturability of its products. before placing an order, the user is cautioned to verify that the information being relied upon is current. allegro?s products are not to be used in life support devices or systems, if a failure of an allegro product can reasonably be expected to cause the failure of that life support device or system, or to affect the safety or effectiveness of that device or system. the in for ma tion in clud ed herein is believed to be ac cu rate and reliable. how ev er, allegro microsystems, inc. assumes n o re spon si bil i ty for its use; nor for any in fringe ment of patents or other rights of third parties which may result from its use. for the latest version of this document, visit our website: www.allegromicro.com allegro microsystems, inc. 115 northeast cutoff worcester, massachusetts 01615-0036 u.s.a. 1.508.853.5000; www.allegromicro.com allegro microsystems offers an industry-leading range of ionization and photoelectric smoke detector ics. for a current listing, please visit our website at: www.allegromicro.com package a, 16-pin dip branded face 10.92 max 0.38 min 5.33 max +0.51 ?0.38 0.13 min c seating plane 16x 0.25 m c 2.54 bsc 7.62 bsc a a terminal #1 mark area +0.25 ?0.38 1.52 3.30 +1.65 ?0.38 3.30 +0.76 ?0.25 6.35 0.460.10 +0.64 ?0.38 19.05 +0.10 ?0.05 0.25 for reference only; not for tooling use (reference ms-001bb) dimensions in millimeters dimensions exclusive of mold flash, gate burrs, and dambar protrusions exact case and lead configuration at supplier discretion within limits shown 2 1 16
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