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M75012 Dataheets PDF



Part Number M75012
Manufacturers Mosdesign
Logo Mosdesign
Description PHOTOELECTRIC SMOKE DETECTOR
Datasheet M75012 DatasheetM75012 Datasheet (PDF)

www.DataSheet4U.com MOSDESIGN SEMICONDUCTOR CORP. SMOKE DETECTOR PHOTOELECTRIC SMOKE DETECTOR WITH INTERCONNECT GENERAL DESCRIPTION M75012 The M75012 is a very low-power IC providing all of the required features for a photoelectric type smoke detector. This device can be used in conjunction with an infrared photoelectric chamber to sense scattered light from smoke particles. A variable-gain photo amplifier can be directly interfaced to an infrared emitter / detector pair. The amplifier gai.

  M75012   M75012


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www.DataSheet4U.com MOSDESIGN SEMICONDUCTOR CORP. SMOKE DETECTOR PHOTOELECTRIC SMOKE DETECTOR WITH INTERCONNECT GENERAL DESCRIPTION M75012 The M75012 is a very low-power IC providing all of the required features for a photoelectric type smoke detector. This device can be used in conjunction with an infrared photoelectric chamber to sense scattered light from smoke particles. A variable-gain photo amplifier can be directly interfaced to an infrared emitter / detector pair. The amplifier gain levels are determined by two external capacitors that are then internally selected depending on the operating mode. Low gain is selected during standby and timer modes. During a local alarm this low gain is increased ( internally ) by ~ 10% to reduce false triggering. High gain is used during the push-button test and during standby to periodically monitor the chamber sensitivity. FEATURES ‧ Interconnect up to 50 detectors. ‧ Piezoelectric horn driver. ‧ Power-on reset. ‧ Built-in circuits to reduce false triggering. ‧ 6V to 12V operating voltage range. ‧ ESD-Protection circuitry on all pins. ‧ Temporal horn pattern. APPLICATIONS ‧ Smoke detector. PIN ASSIGNMENT M75012P C1 C2 DETECT STROBE VDD IRED I/O HORN1 8 9 1 16 TEST TRIP VSS OSCR OSCC LED FEEDBACK HORN2 1/10 2006-10-05 MOSDESIGN SEMICONDUCTOR CORP. SMOKE DETECTOR PHOTOELECTRIC SMOKE DETECTOR WITH INTERCONNECT ABSOLUTE MAXIMUM RATING Parameter Supply Voltage Range Input Voltage Range Input Current Operating Temperature Range Storage Temperature Range Sym. VDD VIN IIN TA TS Rating -0.5 ~ 13 -0.3 to VDD + 0.3 10 -25 ~ 75 -55 to 125 M75012 Unit V V mA ℃ ℃ PIN AND CIRCUIT DESCRIPTION Pin No Pin Name Description A capacitor connected to this pin determines the gain of the photo amplifier during the push-to-test mode and during the chamber monitor test. A typical value for this high-gain mode is 0.047μF but should be selected based on the photo chamber background reflections reaching the detector and the desired level of sensitivity. Ae ≒ 1 + ( C1 / 10 ) where C1 is in pF. Ae should not exceed 10,000. A capacitor connected to this pin determines the gain of the photo amplifier during standby. A typical value for this low-gain mode is 4700 pF but should be selected based on a specific photo chamber and the desired level of sensitivity to smoke. Ae ≒ 1 + ( C2 / 10 ) where C2 is in pF. Ae should not exceed 10,000. This is the input to the photo amplifier and is connected to the cathode of the photo diode. The photo diode is operated at zero bias and should have low darkleakage current and low capacitance. This output provides a strobed , regulated voltage of VDD-5V. The minus side of all internal and external photo amplifier circuitry is referenced to this pin. This pin is connected to the most-positive supply potential and can range from 6V to 12V with respect to VSS. This output provides a pulsed base current for the external NPN transistor , which drives the IR emitter. Its beta should be greater than 100. The IRED output is not active , to minimize noise impact , when the horn and visible LED outputs are active. A connection at this pin allows multiple smoke detectors to be interconnected. If a local smoke condition occurs , this pin is driven high. As an input , this pin is sampled nominally every 1.35 seconds during standby. Any local-alarm condition causes this pin to be ignored as an input. 7 I/O An internal NMOS device acts as a charge dump to aid in applications involving a large ( distributed ) capacitance. The charge dump is activated at the end of local or test alarm. This pin also has an on-chip pull-down resistor and must be left unconnected if not used. In application , there is a series currentlimiting resistor to other smoke alarms. These three 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 and the FEEDBACK input to the feedback electrode. 1 C1 2 C2 3 4 5 DETECT STROBE VDD 6 IRED 8 9 10 HORN1 HORN2 A continuous modulated tone indicates either a local or remote alarm condition. A short ( 10ms ) chirp FEEDBACK indicates a low-battery chirp occurs almost simultaneous with the visible LED flash. If the FEEDBACK pin is not used , it must be connected to VDD or VSS. 2/10 2006-10-05 MOSDESIGN SEMICONDUCTOR CORP. SMOKE DETECTOR PHOTOELECTRIC SMOKE DETECTOR WITH INTERCONNECT M75012 This open-drain NMOS output is used to directly drive a visible LED. The low-battery test does not occur coincident with any other test or alarm signal. The LED also indicates detector status as follows (with component values as in the typical application , all times nominal): 11 LED Standby ─ Pulses every 43 seconds. Local Smoke ─ Pulses every 0.67 seconds. Remote Alarm ─ No pulses. Test Mode ─ Pulses every 0.67 seconds. 12 OSCC A capacitor between this pin and.


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