MOTOROLA
SEMICONDUCTOR TECHNICAL DATA
Photoelectric Smoke
Detector IC with I/O
The CMOS MC145010 is an advanced smoke detector component
containing sophisticated very–low–power analog and digital circuitry. The IC is
used with an infrared photoelectric chamber. Detection is accomplished by
sensing scattered light from minute smoke particles or other aerosols. When
detection occurs, a pulsating alarm is sounded via on–chip push–pull drivers
and an external piezoelectric transducer.
The variable–gain photo amplifier allows direct interface to IR detectors
(photodiodes). Two external capacitors, C1 and C2, C1 being the larger,
determine the gain settings. Low gain is selected by the IC during most of the
standby state. Medium gain is selected during a local–smoke condition. High gain
is used during pushbutton test. During standby, the special monitor circuit which
periodically checks for degraded chamber sensitivity uses high gain, also.
The I/O pin, in combination with VSS, can be used to interconnect up to 40
units for common signaling. An on–chip current sink provides noise immunity
when the I/O is an input. A local–smoke condition activates the short–circuit–
protected I/O driver, thereby signaling remote smoke to the interconnected
units. Additionally, the I/O pin can be used to activate escape lights, enable
auxiliary or remote alarms, and/or initiate auto–dialers.
While in standby, the low–supply detection circuitry conducts periodic checks
using a pulsed load current from the LED pin. The trip point is set using two
external resistors. The supply for the MC145010 can be a 9 V battery.
A visible LED flash accompanying a pulsating audible alarm indicates a
local–smoke condition. A pulsating audible alarm with no LED flash indicates a
remote–smoke condition. A beep or chirp occurring virtually simultaneously
with an LED flash indicates a low–supply condition. A beep occurring half–way
between LED flashes indicates degraded chamber sensitivity. A low–supply
condition does not affect the smoke detection capability if VDD ≥ 6 V. Therefore,
the low–supply condition and degraded chamber sensitivity can be further
distinguished by performing a pushbutton (chamber) test.
• Circuit is designed to operate in smoke detector systems that comply with
UL217 and UL268 Specifications
MC145010
16
1
P SUFFIX
PLASTIC DIP
CASE 648–08
16
1
DW SUFFIX
SOIC PACKAGE
CASE 751G–03
ORDERING INFORMATION
MC145010P PLASTIC DIP
MC145010DW SOIC PACKAGE
PIN ASSIGNMENT
C1
1
16
Test
C2
2
15
Low–Supply
Trip
Detect
3
14
VSS
Strobe
4
13
R1
• Power–On Reset Places IC in Standby Mode (Non–Alarm State)
VDD
5
12
Osc
• Electrostatic Discharge (ESD) and Latch Up Protection Circuitry on All Pins
IRED
6
11
LED
I/O
7
10
Feedback
Brass
8
9
• Operating Voltage Range: 6 to 12 V
• Operating Temperature Range: – 10 to 60°C
• Average Supply Current: 12 µA
• Chip Complexity: 2000 FETs, 12 NPNs, 16 Resistors, and 10 Capacitors
• Ideal for battery powered applications.
Silver
REV 4
4–24
www.motorola.com/semiconductors
Motorola Sensor Device Data
