M75012 Datasheet, PDF (3/10 Pages) List of Unclassifed Manufacturers – PHOTOELECTRIC SMOKE DETECTOR WITH INTERCONNECT

一華半導體股份有限公司
MOSDESIGN SEMICONDUCTOR CORP.
PHOTOELECTRIC SMOKE DETECTOR
WITH INTERCONNECT
SMOKE DETECTOR
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)：
Standby ─ Pulses every 43 seconds.
11
LED
Local Smoke ─ Pulses every 0.67 seconds.
Remote Alarm ─ No pulses.
Test Mode ─ Pulses every 0.67 seconds.
A capacitor between this pin and VDD, along with a parallel resistor , forms part of a two-terminal
12
OSCC oscillator and sets the internal clock low time. With component values as shown , this nominal time is 11
ms and essentially the oscillator period.
A resistor between this pin and OSCC (pin 12 ) is part of the two-terminal oscillator and sets the internal
13
OSCR clock high time , which is also the I_RED pulse width. With component values as shown , this nominal time is
105μs .
14
VSS This pin is connected to the most negative supply potential ( usually ground ).
This pin is connected to an external voltage which determines the low-supply alarm threshold. The trip
15
TRIP voltage is obtained through a resistor divider connected between the VDD and LED pins. The low-supply
alarm threshold voltage ( in volts ) ≒ ( 5R15/R14 ) + 5 where R15 and R14 are in the same units.
This pin has an internal pull-down device and is used to manually invoke a test mode. The Push-to-Test
Mode is initiated by a high logic level on this pin ( usually the depression of a normally open push-button
switch to VDD ). After one oscillator cycle, I_RED pulse every 336 ms ( nominal ) and amplifier gain is
increased by internal selection of C1. Background reflections in the smoke chamber can be used to
16
TEST simulate a smoke condition. After the third I_RED pulse , a successful test ( three consecutive simulated
smoke conditions ) activates the horn drivers and the I/O pin. When the push-button is released , the input
returns to VSS due to the internal pull down. After one oscillator cycle , the amplifier gain returns to
normal and after three additional I_RED pulse ( less than one second ) , the device exits this mode and returns
to standby.
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2006-10-05