Freescale Semiconductor
Technical Data
MC145010
Rev 7.0, 05/2006
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
push button 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 V
SS
, 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 V
DD
≥
6 V. Therefore, the low-supply
condition and degraded chamber sensitivity can be further distinguished by
performing a push button (chamber) test.
Features
•
•
•
•
•
•
•
•
Circuit is designed to operate in smoke detector systems that comply with
UL217 and UL268 Specifications
Operating Voltage Range: 6 to 12 V
Operating Temperature Range: - 10 to 60°C
Average Supply Current: 12
µA
Power-On Reset Places IC in Standby Mode (Non-Alarm State)
Electrostatic Discharge (ESD) and Latch Up Protection Circuitry on All Pins
Chip Complexity: 2000 FETs, 12 NPNs, 16 Resistors, and 10 Capacitors
Ideal for battery powered applications.
ORDERING INFORMATION
Device
MC145010P
MC145010ED
MC145010DW
MCZ145010EG/EGR2
-55 to +125°C
751G-04
16 Lead SOICW
Temp. Range
Case No.
648-08
Package
16 Lead Plastic Dip
MC145010
PHOTOELECTRIC SMOKE
DETECTOR IC WITH I/O
P SUFFIX
ED SUFFIX (PB-FREE)
PLASTIC DIP
CASE 648-08
DW SUFFIX
EG SUFFIX (PB-FREE)
SOICW
CASE 751G-04
C1
C2
Detect
Strobe
V
DD
IRED
I/O
Brass
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
Test
Low-Supply
Trip
V
SS
R1
OSC
LED
Feedback
Silver
Figure 1. Pin Connections
© Freescale Semiconductor, Inc., 2006. All rights reserved.
C1 C2
1 2
Detect
3
AMP
V
DD
- 3.5 V
REF
Gain
Zero
Gate
On/off
-
Comp
+
Smoke
7
Alarm
Logic
I/O
Low Supply
OSC
R1
Test
12
13
16
OSC
Timing
Logic
Horn Modulator
And Driver
8
9
10
6
11
Brass
Silver
Feedback
IRED
LED
Gate
On/off
V
DD
- 5.0
VREF
-
Comp
+
Strobe
Low-supply
Trip
4
15
PIN 5 = V
DD
PIN 14 = V
SS
Figure 2. Block Diagram
Table 1. Maximum Ratings
(1)
(Voltages referenced to V
SS
)
Rating
DC Supply Voltage
DC Input Voltage
C1, C2, Detect
OSC, Low-Supply Trip
I/O
Feedback
Test
DC Input Current per Pin
DC Output Current per Pin
DC Supply Current, VDD and VSS Pins
Power Dissipation in Still Air
5 Seconds
Continuous
Storage Temperature Range
Lead Temperature, 1 mm From Case for 10 Seconds
Symbol
V
DD
V
IN
Value
-0.5 to +15
-0.25 to V
DD
+0.25
-0.25 to V
DD
+0.25
-0.25 to V
DD
+10
-15 to +25
-1.0 to V
DD
+0.25
±10
±25
+25 / -150
1200
350
(3)
(2)
Unit
V
V
I
IN
I
OUT
I
DD
P
D
mA
mA
mA
mW
T
STG
T
L
-55 to +125
5.0
°C
°C
1. Maximum Ratings are those values beyond which damage to the device may occur. Functional operation should be restricted to the limits
in the Electrical Characteristics tables.
2. Derating: -12 mW/°C from 25° to 60°C.
3. Derating -3.5 mW/°C from 25° to 60°C.
This device contains circuitry to protect the inputs against damage due to high static voltages or electric fields; however, it is advised normal
precautions be taken to avoid application of any voltage higher than maximum rated voltages to this high impedance circuit. For proper
operation, it is recommended V
IN
and V
OUT
be constrained to the range V
SS
≤
(V
IN
or V
OUT
)
≤
V
DD
.
MC145010
2
Sensors
Freescale Semiconductor
Table 2. Electrical Characteristics
(T
A
= -10 to 60°C unless otherwise indicated. Voltages referenced to V
SS
.)
Characteristics
Operating Voltage
Supply Threshold voltage, Low-Supply Alarm
Low-Supply Trip: VIN = VDD/3
Average Operating Supply Current (per Package)
Standby Configured per
Figure 8
Peak Supply Current (per Package)
During Strobe ON, IRED OFF Configured per
Figure 8
During Strobe ON, IRED ON Configured per
Figure 8
Low-Level Input Voltage
I/O
Feedback
Test
High-Level Input Voltage
I/O
Feedback
Test
Input Current
OSC, Detect – V
IN
= V
SS
or V
DD
Low-Supply Trip – V
IN
= V
SS
or V
DD
Feedback – V
IN
= V
SS
or V
DD
Low -Level Input Current
Test – V
IN
= V
SS
or V
DD
Pull-Down Current
Test – V
IN
= V
DD
I/O – No Local Smoke, V
IN
= V
DD
I/O – No Local Smoke, V
IN
= 17 V
Low-Level Output Voltage
LED – I
OUT
= 10 mA
Silver, Brass – I
OUT
= 16 mA
High-Level Output Voltage
Silver, Brass – I
OUT
= 16 mA
Output Voltage (For Line Regulations, See Pin Descriptions)
Strobe – Inactive, I
OUT
= -1 µA
Active, I
OUT
= 100 µA to 500 µA (Load Regulation)
IRED – Inactive, I
OUT
= 1 µA
Active, I
OUT
= 6 µA (Load Regulation)
High-Level Output Current
I/O – Local Smoke, V
OUT
= 4.5 V
I/O – Local Smoke, V
OUT
= V
SS
(Short Circuit Current)
Off-State Output Leakage Current
LED – V
OUT
= V
SS
or V
DD
Common Mode
C1, C2, Detect, Voltage Range – Local Smoke, Push Button
Test, or Chamber Sensitivity Test
Smoke Comparator
Internal Reference Voltage – Local Smoke, Push Button
Test, or Chamber Sensitivity Test
1. T
A
= 25°C only.
Symbol
V
DD
V
TH
I
DD
i
DD
V
DD
/V
DC
—
—
12.0
Min
6.0
6.5
—
Typ
—
—
—
Max
12.0
7.8
12.0
µA
mA
12.0
12.0
9.0
9.0
9.0
9.0
9.0
9.0
12.0
12.0
12.0
12.0
—
—
—
—
—
3.2
6.3
8.5
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
2.0
3.0
V
1.5
2.7
7.0
V
—
—
—
nA
±100
±100
±100
-1.0
µA
µA
9.0
9.0
12.0
6.5
6.5
6.5
—
9.0
—
9.0
6.5
12.0
12.0
—
0.5
25.0
—
—
—
5.5
V
DD
– 0.1
V
DD
– 4.40
—
2.25
(1)
-4
—
—
V
DD
– 4
—
—
—
—
—
—
—
—
10
100
140
V
0.6
1.0
V
—
V
—
V
DD
– 5.30
0.1
3.75
1
mA
—
-16
ΧA
±1.0
V
V
DD
– 2
V
—
V
DD
– 3.08
—
V
DD
– 3.92
Unit
V
V
V
IL
V
IH
I
IN
I
IL
I
IH
V
OL
V
OH
V
OUT
I
OH
I
OZ
V
IC
V
REF
MC145010
Sensors
Freescale Semiconductor
3
Table 3. AC Electrical Characteristics
Reference Timing Diagram
Figure 6
and
Figure 7.
(T
A
= 25°C, V
DD
= 9.0 V, Component values from
Figure 8:
R1 = 100.0 KΩ,
C3 = 1500.0 pF, R2 = 10.0 MΩ.)
No.
1
Period
(1)
Characteristics
Oscillator
Free-Running Sawtooth Measured at Pin 12
LED Pulse Period
No Local Smoke, and No Remote Smoke
Remote Smoke, but No Local Smoke
Local Smoke or Push Button Test
LED Pulse Width and Strobe Pulse Width
IRED Pulse Period
Smoke Test
Chamber Sensitivity Test without Local Smoke
Push Button Test
IRED Pulse Width
IRED Rise Time
IRED Fall Time
Silver and Brass Modulation Period
Local or Remote Smoke
Silver and Brass Duty Cycle
Local or Remote Smoke
Silver and Brass Chirp Pulse Period
Low Supply or Degraded Chamber Sensitivity
Silver and Brass Chirp Pulse Width
Low Supply or Degraded Chamber Sensitivity
Rising Edge on I/O to Smoke Alarm Response Time
Remote Smoke, No Local Smoke
Strobe Out Pulse Period
Smoke Test
Chamber Sensitivity Test without Local Smoke
Low Supply Test without Local Smoke
Push Button Test
Symbol
1/f
OSC
t
LED
Clocks
1
Min
9.5
Max
11.5
Unit
ms
s
4096
—
64
1
38.9
—
0.60
9.5
47.1
—
0.74
11.5
ms
s
1024
4096
32
T
f1
—
—
—
—
4096
1
—
1024
4096
4096
—
9.67
38.9
0.302
94
—
—
297
73
38.9
9.5
—
9.67
38.9
38.9
0.302
11.83
47.1
0.370
116
30
200
363
%
77
s
47.1
ms
11.5
ms
800
s
11.83
47.1
47.1
0.370
µs
µs
ms
2
3
4
5
t
w(LED)
,
t
w(STB)
t
IRED
6
7
8
9
10
11
11
12
13
14
15
t
w(IRED)
t
r
t
f
t
MOD
t
ON
/t
MOD
t
CH
tw
(CH)
t
RR
t
STB
16
17
18
19
1. Oscillator Period T (= T
r
+ T
f
) is determined by the external components R1, R2, and C3 where T
r
= (0.6931) R
2
x C
3
and
T
f
= (0.6031) R
1
x C
3
.
The other timing characteristics are some multiple of the oscillator timing shown in the table.
MC145010
4
Sensors
Freescale Semiconductor
Table 4. Pin Description
Pin
1
Symbol
C1
Description
A capacitor connected to this pin, shown in
Figure 8,
determines the gain of the on-chip photo amplifier during push button
test and chamber sensitivity test (high gain). The capacitor value is chosen such that the alarm is tripped from background
reflections in the chamber during push button test.
A
v
ª 1 + (C1/10) where C1 is in pF. CAUTION: The value of the closed-loop gain should not exceed 10,000.
A capacitor connected to this pin as shown in
Figure 8
determines the gain of the on-chip photo amplifier except during
push button or chamber sensitivity tests. A
v
≈
1 + (C2/10) where C2 is in pF. This gain increases about 10% during the
IRED pulse, after two consecutive local smoke detections.
Resistor R14 must be installed in series with C2. R14
≈
[1/(12√C2)] - 680 where R14 is in ohms and C2 is in farads.
2
C2
3
DETECT This input to the high-gain pulse amplifier is tied to the cathode of an external photodiodes. The photodiodes should have
low capacitance and low dark leakage current. The diode must be shunted by a load resistor and is operated at zero bias.
The Detect input must be ac/dc decoupled from all other signals, V
DD
, and V
SS
. Lead length and/or foil traces to this pin
must be minimized, also. See
Figure 9.
STROBE This output provides a strobed, regulated voltage referenced to V
DD
. The temperature coefficient of this voltage is
±
0.2%/
°C
maximum from - 10° to 60°C. The supply-voltage coefficient (line regulation) is
±
0.2%/V maximum from 6 to 12 V.
Strobe is tied to external resistor string R8, R9, and R10.
V
DD
IRED
This pin is connected to the positive supply potential and may range from +6 to +12 V with respect to V
SS
. CAUTION: In
battery-powered applications, reverse-polarity protection must be provided externally.
This output provides pulsed base current for external NPN transistor Q1 used as the infrared emitter driver. Q1 must have
β ≥
100. At 10 mA, the temperature coefficient of the output voltage is typically + 0.5%/°C from - 10° to 60°C. The supply-
voltage coefficient (line regulation) is
±
0.2%/V maximum from 6 to 12 V. The IRED pulse width (active-high) is determined
by external components R1 and C3. With a 100 kΩ/1500 pF combination, the nominal width is 105
µs.
To minimize noise
impact, IRED is not active when the visible LED and horn outputs are active. IRED is active near the end of Strobe pulses
for Smoke Tests, Chamber Sensitivity Test, and Push button Test.
This pin can be used to connect up to 40 units together in a wired-OR configuration for common signaling. V
SS
is used as
the return. An on-chip current sink minimizes noise pick up during non-smoke conditions and eliminates the need for an
external pull-down resistor to complete the wired-OR. Remote units at lower supply voltages do not draw excessive current
from a sending unit at a higher supply voltage.
I/O can also be used to activate escape lights, auxiliary alarms, remote alarms, and/or auto-dialers.
As an input, this pin feeds a positive-edge-triggered flip-flop whose output is sampled nominally every 625 ms during
standby (using the recommended component values). A local-smoke condition or the push button-test mode forces this
current-limited output to source current. All input signals are ignored when I/O is sourcing current. I/O is disabled by the
on-chip power-on reset to eliminate nuisance signaling during battery changes or system power-up. If unused, I/O must
be left unconnected.
This half of the push-pull driver output is connected to the metal support electrode of a piezoelectric audio transducer and
to the horn-starting resistor. A continuous modulated tone from the transducer is a smoke alarm indicating either local or
remote smoke. A short beep or chirp is a trouble alarm indicating a low supply or degraded chamber sensitivity.
This half of the push-pull driver output is connected to the ceramic electrode of a piezoelectric transducer and to the horn-
starting capacitor.
4
5
6
7
I/O
8
BRASS
9
10
11
SILVER
FEEDBA This input is connected to both the feedback electrode of a self-resonating piezoelectric transducer and the horn-starting
CK
resistor and capacitor through current-limiting resistor R4. If unused, this pin must be tied to V
SS
or V
DD
.
LED
This active-low open-drain output directly drives an external visible LED at the pulse rates indicated below. The pulse width
is equal to the OSC period.
The load for the low-supply test is applied by this output. This low-supply test is non-coincident with the smoke tests,
chamber sensitivity test, push button test, or any alarm signals.
The LED also provides a visual indication of the detector status as follows, assuming the component values shown in
Figure 8:
Standby (includes low-supply and chamber sensitivity tests) - Pulses every 43 seconds (nominal) Local Smoke
- Pulses every 0.67 seconds (nominal) Remote Smoke - No pulses
Push button Test - Pulses every 0.67 seconds (nominal)
This pin is used in conjunction with external resistor R2 (10 MΩ) to V
DD
and external capacitor C3 (1500 pF) to V
DD
to
form an oscillator with a nominal period of 10.5 ms.
This pin is used in conjunction with resistor R1 (100 kΩ) to pin 12 and C3 (1500 pF, see pin 12 description) to determine
the IRED pulse width. With this RC combination, the nominal pulse width is 105
µs.
This pin is the negative supply potential and the return for the I/O pin. Pin 14 is usually tied to ground.
12
13
14
15
OSC
R1
VSS
LOW-
This pin is connected to an external voltage which determines the low-supply alarm threshold. The trip voltage is obtained
SUPPLY through a resistor divider connected between the V
DD
and LED pins. The low-supply alarm threshold voltage (in volts)
≈
TRIP
(5R7/R6) + 5 where R6 and R7 are in the same units.
MC145010
Sensors
Freescale Semiconductor
5
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