Freescale Semiconductor
Technical Data
MC14467-1
Rev 5.0, 3/2007
Low-Power CMOS
Ionization Smoke Detector IC
The MC14467-1, when used with an ionization chamber and a small
number of external components, will detect smoke. When smoke is sensed,
an alarm is sounded via an external piezoelectric transducer and internal
drivers. This circuit is designed to operate in smoke detector systems that
comply with UL217 and UL268 specifications.
Features
•
•
•
•
•
•
•
•
•
•
Ionization Type with On-Chip FET Input Comparator
Piezoelectric Horn Driver
Guard Outputs on Both Sides of Detect Input
Input-Production Diodes on the Detect Input
Low-Battery Trip Point, Internally Set, can be Altered Via External
Resistor
Detect Threshold, Internally Set, can be Altered Via External Resistor
Pulse Testing for Low Battery Uses LED for Battery Loading
Comparator Outputs for Detect and Low Battery
Internal Reverse Battery Protection
Pb-Free Packaging Designated by Suffix Code ED and EG
MC14467-1
LOW-POWER CMOS
IONIZATION
SMOKE DETECTOR IC
P SUFFIX
ED SUFFIX
(PB-FREE)
16-LEAD
PLASTIC DIP
CASE 648-08
EG SUFFIX
(PB-FREE)
16-LEAD
SOICW
CASE 751G-04
ORDERING INFORMATION
Device
MC14467P1
648-08
MC14467ED1
MCZ14467EG/R2
751G-04
SOICW
Plastic Dip
Case No.
Package
DETECT
COMP. OUT
N/C
LOW V SET
LOW V
COMP. OUT
LED
VDD
TIMING
RESISTOR
FEEDBACK
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
GUARD HI-Z
DETECT INPUT
GUARD LO-Z
SENSITIVITY SET
OSC CAPACITOR
SILVER
BRASS
VSS
DETECT
COMP. OUT
N/C
LOW V SET
LOW V
COMP. OUT
LED
VDD
TIMING
RESISTOR
FEEDBACK
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
GUARD HI-Z
DETECT INPUT
GUARD LO-Z
SENSITIVITY
SET
OSC
CAPACITOR
SILVER
BRASS
VSS
Figure 1. Pin Connections
© Freescale Semiconductor, Inc., 2007. All rights reserved.
V
DD
Priezoelectric
Horn Driver
8
4
–
+
Low Battery Comp.
Latch
10
V
DD
11
80 K
3
1045 K
V
DD
7
Oscillator
Timer
12
V
DD
5
13
+
–
15
6
9
Led Driver
Latch
1
Detect Input
V
DD
1125 K
14
+
–
Lo-Z
Active
Guard
Figure 2. Block Diagram
Table 1. Maximum Ratings
(1)
(Voltages referenced to V
SS
)
Rating
DC Supply Voltage
Input Voltage, All Inputs Except Pin 8
DC Current Drain per Input Pin, Except Pin 15 = 1 mA
DC Current Drain per Output Pin
Operating Temperature Range
Storage Temperature Range
Reverse Battery Time
Symbol
V
DD
V
IN
I
I
T
A
T
STG
t
RB
Value
−0.5
to + 15
−0.25
to V
DD
+ 0.25
10
30
−10
to +60
−55
to + 125
5.0
Unit
V
V
mA
mA
°C
°C
s
1. Maximum Ratings are those values beyond which damage to the device may occur. This device contains circuitry to protect the inputs
against damage due to high static voltages or electric fields; however, it is advised that 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 that except for pin 8,
V
IN
and V
OUT
be constrained to the range V
SS
≤
(V
IN
or V
OUT
) V
DD
. For pin 8, refer to the Electrical Characteristics.
MC14467-1
2
Sensors
Freescale Semiconductor
Table 2. Recommended Operating Conditions
(Voltages referenced to V
SS
)
Parameter
Supply Voltage
Timing Capacitor
Timing Resistor
Battery Load (Resistor or LED)
Symbol
V
DD
—
—
—
Value
9.0
0.1
8.2
10
Unit
V
µF
MΩ
mA
Table 3. Electrical Characteristics
(Voltages referenced to V
SS
, T
A
= 25
°
C)
Characteristic
Operating Voltage
Output Voltage
Piezoelectric Horn Drivers (I
OH
=
-16
mA)
Comparators (I
OH
=
-30
µA)
Piezoelectric Horn Drivers (I
OL
= +16 mA)
Comparators (I
OL
= +30
µA)
Output Voltage - LED Driver, I
OL
= 10 mA
Output Impedance, Active Guard
Pin 14
Pin 16
Operating Current (R
bias
= 8.2 MΩ)
Input Current - Detect (40% R.H.)
Internal Set Voltage
Low Battery
Sensitivity
Hysteresis
Offset Voltage (measured at Vin = VDD/2
Active Guard
Detect Comparator
Input Voltage Range, Pin 8
Input Capacitance
Common Mode Voltage Range, Pin 15
Symbol
V
DD
V
OH
7.2
9.0
7.2
9.0
7.2
9.0
9.0
9.0
12.0
9.0
9.0
—
9.0
9.0
9.0
V
IN
C
IN
V
CM
—
—
—
6.3
8.5
—
—
—
—
—
—
—
—
7.2
47
75
—
—
VSS - 10
—
0.6
—
8.8
—
0.1
—
—
—
5.0
—
—
—
50
100
—
—
—
5.0
—
—
—
0.9
0.5
3.0
10
1000
9.0
12.0
±
1.0
7.8
53
150
±
100
±
50
VDD + 10
—
VDD
-
2
V
pF
V
µA
pA
V
%V
DD
mV
mV
V
DD
V
DC
—
Min
6.0
Typ
(1)
—
Max
12
Unit
V
V
V
OL
V
OL
LO-Z
HI-Z
I
DD
I
IN
V
LOW
V
SET
V
HYS
V
OS
V
V
kΩ
1. Data labelled “Typ'' is not to be used for design purposes but is intended as an indication of the IC's potential performance.
MC14467-1
Sensors
Freescale Semiconductor
3
Table 4. Timing Parameters
(C = 0.1
µ
F, R
bias
= 8.2 MΩ, V
DD
= 9.0 V, T
A
= 25
°
C, See
Figure 7)
Characteristics
Oscillator Period
Oscillator Rise Time
Horn Output
(During Smoke)
LED Output
Horn Output
(During Low Battery)
On Time
Off Time
Between Pulses
On Time
On Time
Between Pulses
No Smoke
Smoke
Symbol
t
CI
t
R
PW
ON
PW
OFF
t
LED
PW
ON
t
ON
t
OFF
Min
1.34
32
8.0
120
60
32
8.0
8.0
32
Typ
(1)
1.67
40
10
160
80
40
10
10
40
Max
2.0
48
12
208
104
48
12
12
48
Units
s
ms
ms
ms
ms
s
ms
ms
s
1. Data labelled “Typ” is not to be used for design purposes but is intended as an indication of the IC’s potential performance.
100.0
V
DD
= 9.0 V
DC
10.0
I
D
, Drain Current (mA)
V
DD
= 7.2 V
DC
T
A
= 25°C
10.0
T
A
= 25°C
1.0
I
D
, Drain Current (mA)
1.0
V
DD
= 9.0 V
DC
or 7.2 V
DC
0.1
P-CH Source
And N-CH
Sink Current
0.1
0
1
2
3
4
5
6
7
8
9
10
0.01
0
1
2
3
4
5
6
7
8
9
10
V
DS
, Drain To Source Voltage (V
DC
)
V
DS
, Drain To Source Voltage (V
DC)
Figure 3. Typical LED Output I-V Characteristic
1000.0
TA = 25°C
I
D
, Drain Current (mA)
100.0
V
DD
= 9.0 V
DC
Figure 4. Typical Comparator Output I-V Characteristic
1000.0
T
A
= 25°C
100.0
I
D
, Drain Current (mA)
V
DD
= 9.0 V
DC
10.0
V
DD
= 7.2 V
DC
10.0
V
DD
= 7.2 V
DC
P-CH Source Current
1.0
0
1
2
3
4
5
6
7
8
9
10
1.0
0
1
2
3
4
N-CH Sink Current
5
6
7
8
9
10
V
DS
, Drain To Source Voltage (V
DC
)
V
DS
, Drain To Source Voltage (V
DC
)
Figure 5. Typical P Horn Driver Output I-V Characteristic
MC14467-1
4
Sensors
Freescale Semiconductor
DEVICE OPERATION
Timing
The internal oscillator of the MC14467-1 operates with a
period of 1.67 seconds during no-smoke conditions. Each
1.67 seconds, internal power is applied to the entire IC and a
check is made for smoke, except during LED pulse, Low
Battery Alarm Chirp, or Horn Modulation (in smoke). Every 24
clock cycles a check is made for low battery by comparing
V
DD
to an internal zener voltage. Since very small currents
are used in the oscillator, the oscillator capacitor should be of
a low leakage type.
Detect Circuitry
If smoke is detected, the oscillator period becomes 40 ms
and the piezoelectric horn oscillator circuit is enabled. The
horn output is modulated 160 ms on, 80 ms off. During the off
time, smoke is again checked and will inhibit further horn
output if no smoke is sensed. During smoke conditions the
low battery alarm is inhibited, but the LED pulses at a 1.0 Hz
rate.
An active guard is provided on both pins adjacent to the
detect input. The voltage at these pins will be within 100 mV
of the input signal. This will keep surface leakage currents to
a minimum and provide a method of measuring the input
voltage without loading the ionization chamber. The active
guard op amp is not power strobed and thus gives constant
protection from surface leakage currents. Pin 15 (the Detect
input) has internal diode protection against static damage.
Sensitivity/Low Battery Thresholds
Both the sensitivity threshold and the low battery voltage
levels are set internally by a common voltage divider (please
see
Figure 2)
connected between VDD and VSS. These
voltages can be altered by external resistors connected from
pins 3 or 13 to either VDD or VSS. There will be a slight
interaction here due to the common voltage divider network.
The sensitivity threshold can also be set by adjusting the
smoke chamber ionization source.
Test Mode
Since the internal op amps and comparators are power
strobed, adjustments for sensitivity or low battery level could
be difficult and/or time-consuming. By forcing Pin 12 to VSS,
the power strobing is bypassed and the outputs, Pins 1 and
4, constantly show smoke/no smoke and good battery/low
battery, respectively. Pin 1 = VDD for smoke and
Pin 4 = VDD for low battery. In this mode and during the
10 ms power strobe, chip current rises to approximately
50
µA.
LED Pulse
The 9-volt battery level is checked every 40 seconds
during the LED pulse. The battery is loaded via a 10 mA
pulse for 10 ms. If the LED is not used, it should be replaced
with an equivalent resistor such that the battery loading
remains at 10 mA.
Hysteresis
When smoke is detected, the resistor/divider network that
sets sensitivity is altered to increase sensitivity. This yields
approximately 100 mV of hysteresis and reduces false
triggering.
1M
1M
Test
1
2
3
4
330
Ω
5
6
7
8.2 MΩ
0.1 µF
+
9.0 V
8
MC14467-1
16
15
14
13
12
11
10
9
0.1 µF
1.5 MΩ*
0.001* µF
220 kΩ*
*NOTE: Component values may change depending on type of piezoelectric horn used.
Figure 6. Typical Application as Ionization Smoke Detector
MC14467-1
Sensors
Freescale Semiconductor
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