ETC RE46C122

R&E International
RE46C122
CMOS Ionization Smoke Detector ASIC with Interconnect and Timer Mode
Preliminary Product Specification
General Description
Features
The RE46C122 is low power CMOS ionization type
smoke detector IC. With few external components this
circuit will provide all the required features for an
ionization type smoke detector.
•
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•
•
•
•
•
•
•
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An internal oscillator strobes power to the smoke
detection circuitry for 10.5mS every 1.66 seconds to
keep standby current to a minimum. A check for a low
battery condition is performed every 40 seconds when
in standby. The temporal horn pattern supports the
NFPA 72 emergency evacuation signal.
An interconnect pin allows multiple detectors to be
connected such that when one units alarms all units will
sound.
Guard Outputs for Ion Detector Input
+/-0.75pA Detect Input Current
Internal Reverse Battery Protection
Low Quiescent Current Consumption (<6uA)
Available in 16L PDIP or 16L N SOIC
ESD Protection on all Pins
Internal Low Battery Detection
Interconnect up to 40 Detectors
10 Minute Timer for Sensitivity Control
Compatible with Allegro A5367
Pin Configuration
TSTART
1
16
GUARD2
IO
2
15
DETECT
3
14
GUARD1
4
13
VSEN
LED
5
12
OSCAP
VDD
6
11
HS
RBIAS
7
10
HB
FEED
8
9
An internal 10 minute timer allows for a separate button
to be used for reduced sensitivity mode.
Although this device was designed for smoke detection
utilizing an ionization chamber it could be used in a
variety of security applications.
LBADJ
TSTROBE
Utilizing low power CMOS technology the RE46C122
was designed for use in smoke detectors that comply
with Underwriters Laboratory Specification UL217 and
UL268.
VSS
ABSOLUTE MAXIMUM RATINGS
PARAMETER
Supply Voltage
Input Voltage Range Except FEED
FEED Input Voltage Range
Reverse Battery Time
Input Current except FEED
Operating Temperature
Storage Temperature
Maximum Junction Temperature
SYMBOL
VDD
Vin
Vinfd
TRB
Iin
TA
TSTG
TJ
VALUE
15
-.3 to Vdd +.3
-10 to +22
5
10
-10 to 60
-55 to 125
150
UNITS
V
V
V
S
mA
°C
°C
°C
Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are
stress ratings only and operation at these conditions for extended periods may affect device reliability.
This product utilizes CMOS technology with static protection; however proper ESD prevention procedures should be used
when handling this product. Damage can occur when exposed to extremely high static electrical charge.
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DS-RE46C122-060104
This datasheet contains PROPRIETARY and CONFIDENTIAL information.
RE46C122
CMOS Ionization Smoke Detector ASIC with Interconnect and Timer Mode
Preliminary Product Specification
R&E International
DC Electrical Characteristics at TA = 25°C, VDD=9V, OSCAP=.1uF, RBIAS=8.2MΩ, VSS=0V (unless
otherwise noted)
Symbol
Test
Pin
Supply Voltage
VDD
6
Operating
Supply Current
IDD1
6
RBIAS=8.2MΩ, OSCAP=.1uF
IDD2
6
RBIAS=8.2MΩ, OSCAP=.1uF;Vdd=12V
VIH1
8
VIH2
2
VIH3
1
VIL1
8
VIL2
2
VIL3
1
ILDET1
15
15
Parameter
Input Voltage High
Input Voltage Low
Input Leakage Low
ILDET2
Input Leakage High
Test Conditions
Min
6
4
6.2
No Local Alarm, IO as an Input
Limits
Typ
Max
Units
12
V
6
uA
9
uA
4.5
V
3
V
4.5
V
4.5
2.7
V
1
V
2.5
V
VDD=9V, DETECT=VSS, 0-40% RH
-0.75
pA
VDD=9V, DETECT=VSS, 85% RH
Note 1
-1.50
pA
No Local Alarm, IO as an Input
ILFD
8
FEED=-10V
-50
uA
IHDET1
15
VDD=9V, DETECT=VDD, 0-40% RH
0.75
pA
IHDET2
15
VDD=9V, DETECT=VDD, 85% RH
Note 1
1.50
pA
IHFD
8
FEED=22V
50
uA
No Alarm, Vio=17V
150
uA
IIOL2
2
Output Off Leakage High
IIOHZ
4,5
Outputs Off
Input Pull Down Current
IPD1
1
TSTART=9V
20
Output High Voltage
VOH1
10,11
IOH=-16mA, VDD=7.2V
6.3
Output Low Voltage
VOL1
10,11
IOL=16mA, VDD=7.2V
.9
V
VOL2
4
IOL=500ua
.5
V
VOL3
5
IOL=10mA, VDD=7.2V
1
V
Output Current
Low Battery Voltage
Internal Sensitivity Set Voltage
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50
1
uA
80
uA
V
IIOL1
2
No Alarm, Vio=Vdd-2V
25
100
uA
IIOH1
2
Alarm, Vio=Vdd-2V or Vio=0V
-4
-16
mA
IIODMP
2
At Conclusion of Local Alarm or Test,
Vio=1V
5
VLB
6
TA=-10 to 60ºC, Note 3
VSET1
13
VSET2
3
mA
7.2
7.5
7.8
V
47
50
53
%VDD
65.5
Facsimile 610.992.0734
%VDD
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DS-RE46C122-060104
This datasheet contains PROPRIETARY and CONFIDENTIAL information.
RE46C122
CMOS Ionization Smoke Detector ASIC with Interconnect and Timer Mode
Preliminary Product Specification
R&E International
DC Electrical Characteristics - Continued
Symbol
Test
Pin
VGOS1
14,15
Guard Amplifier
-50
50
mV
VGOS2
15,16
Guard Amplifier
-50
50
mV
VGOS3
14,15
Smoke Comparator
-50
50
mV
VCM1
14,15
Guard Amplifier, Note 2
2
VDD-.5
V
VCM2
13,15
Smoke Comparator, Note 2
.5
VDD-2
V
Output Impedance
ZOUT
6,8
Guard Amplifier Outputs, Note 2
10
kΩ
Hysteresis
VHYS
13
No Alarm to Alarm Condition
170
mV
Parameter
Offset Voltage
Common Mode Voltage
Test Conditions
Limits
90
130
Note 1: Sample test only
Note 2: Not 100% production tested
Note 3: Production test at room with temperature guardbanded limits.
AC Electrical Characteristics at TA = 25°C, VDD=9V, OSCAP=.1uF, RBIAS=8.2MΩ, VSS=0V (unless
otherwise noted)
Parameter
Oscillator Period
Symbol
Test
Pin
TPER1
12
Min
Limits
Typ
Max
No Alarm Condition
1.34
1.67
2
S
Alarm Condition
37.5
41.5
45.8
mS
Test Conditions
Units
TPER2
12
Oscillator Pulse Width
TPW
5
Operating
9.4
10.5
12.9
mS
LED On Time
TLON
5
Operating
9.4
10.5
12.9
mS
LED Off Time
TLOF1
5
Standby, No Alarm
32
40
48
S
TLOF2
5
Alarm Condition
.8
1
1.2
S
TLOF3
5
Timer Mode, No Alarm
8
10
12
S
THON1
10,11
Operating, Alarm Condition, Note 4
450
500
550
mS
THON2
10,11
Low Battery, No Alarm
9.4
10.5
12.9
mS
THOF1
10,11
Operating, Alarm Condition, Note 4
450
500
550
mS
THOF2
10,11
Operating, Alarm Condition, Note 4
1.35
1.5
1.65
S
Low Battery, No Alarm
32
40
48
S
1.34
1.67
2.0
S
Horn On Time
Horn Off Time
THOF3
10,11
IO Charge Dump Duration
TIODMP
2
At Conclusion of Local Alarm or Test
IO Delay
TIODLY
2
From Start of Local Alarm to IO Active
TIOACT1
2
Minimum Active Interconnect Signal to
Cause a Remote Alarm. IO as Input, No
Local Alarm
TTPER
4
No Alarm
IO Active Time for Remote
Alarm
Timer Period
3
S
.45
.5
S
8
10
12
Min
Note 4 – See timing diagram for Horn Temporal Pattern
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DS-RE46C122-060104
This datasheet contains PROPRIETARY and CONFIDENTIAL information.
RE46C122
CMOS Ionization Smoke Detector ASIC with Interconnect and Timer Mode
Preliminary Product Specification
R&E International
Functional Block Diagram
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DS-RE46C122-060104
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RE46C122
CMOS Ionization Smoke Detector ASIC with Interconnect and Timer Mode
Preliminary Product Specification
R&E International
DEVICE DESCRIPTION and APPLICATION NOTES
Internal Timing – With external components as indicated on the application drawing the period of the
oscillator is nominally 1.67 seconds in standby. Every 1.66 seconds the detection circuitry is powered up
for 10.5mS and the status of the smoke comparator is latched. In addition every 40 seconds the LED
driver is turned on for 10.5mS and the status of the low battery comparator is latched. The smoke
comparator status is not checked during the low battery test, during the low battery horn warning chirp, or
when the horn is on due to an alarm condition.
If an alarm condition is detected the oscillator period increases to 41.5mS.
Due to the low currents used in the oscillator the capacitor on pin 12 should be a low leakage type.
Oscillator accuracy will depend mainly on the tolerance of the RBIAS resistor and OSCAP capacitor.
Smoke Detection Circuit – The smoke comparator compares the ionization chamber voltage to a voltage
derived from a resistor divider across VDD. This divider voltage is available externally on pin 13 (VSEN).
When smoke is detected this voltage is internally increased by 130mV nominal to provide hysteresis and
make the detector less sensitive to false triggering.
Pin 13 (VSEN) can be used to modify the internal set point for the smoke comparator by use of external
resistors to VDD or VSS. Nominal values for the internal resistor divider are indicated on the block
diagram. These internal resistor values can vary by up to ±20% but the resistor matching should be <2%
on any one device. Transmission switches on VSEN and LBADJ prevent any interaction from the external
adjustment resistors.
The guard amplifier and outputs are always active and will be within 50mV of the DETECT input to
reduce surface leakage. The guard outputs also allow for measurement of the DETECT input without
loading the ionization chamber.
Low Battery Detection - An internal reference is compared to the voltage divided VDD supply. The battery
can be checked under load via the LED low side driver output since low battery status is latched at the
end of the 10.5mS LED pulse. Pin 3 (LBADJ) can be used to modify the low battery set point by placing a
resistor to VDD or VSS. Transmission switches on VSEN and LBADJ prevent any interaction from
external adjustment resistance.
LED Pulse – The LED is pulsed on for 10.5mS every 40S in standby. In alarm the LED is pulsed on for
10.5mS every 1S.
Interconnect – Pin 2 (IO) provides the capability to common many detectors in a single system. If a single
unit goes into alarm the IO pin is driven high. This high signal causes the interconnected units to alarm.
The LED flashes every 1S for 10.5mS on the signaling unit and is inhibited on the units that are in alarm
due to the IO signal. An internal sink device on the IO pin helps to discharge the interconnect line. This
charge dump device is active for 1 clock cycle after the unit exits the alarm condition (1.67S).
The interconnect input has a 500mS maximum digital filter. This allows for interconnection to other types
of alarms (carbon monoxide for example) that may have a pulsed interconnect signal.
Testing - By holding pin 12 (OSCAP) low the internal power strobe is active. Functional testing can be
accelerated by driving pin 12 with a 4kHZ square wave however the 10.5mS strobe period must be
maintained for proper operation of the analog circuitry. Please refer to the timing diagrams.
Timer Mode – The transition of pin 1 (TSTART) from a high to low level initiates a ten minute timer.
During this 10 minute period the open drain NMOS on pin 4 (TSTROBE) is strobed on with the internal
clock. A resistor connected to this pin could be used to modify the detector sensitivity for the timer period.
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DS-RE46C122-060104
This datasheet contains PROPRIETARY and CONFIDENTIAL information.
RE46C122
CMOS Ionization Smoke Detector ASIC with Interconnect and Timer Mode
Preliminary Product Specification
R&E International
Typical Application
Figure 2
Notes:
The application of the internal 10 minute timer for reduced sensitivity as shown in Figure 2 may be
covered by United States patent RE. 33920.
C2 should be located as close as possible to the device power pins.
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DS-RE46C122-060104
This datasheet contains PROPRIETARY and CONFIDENTIAL information.
RE46C122
CMOS Ionization Smoke Detector ASIC with Interconnect and Timer Mode
Preliminary Product Specification
R&E International
Timing Diagram (non Timer Mode)
Standby M ode; No Low Battery; No Alarm
Alarm; No Low Battery
Alarm; Low Battery
No Alarm; Low Battery
Oscillator
Pin 15 > Pin 13
1.67S
Pin 13 > Pin 15; 130mV Level Shift on Pin 13
Pin 15 > Pin 13
11mS
Internal Clock
24 Clock Cycles (40 S)
24 Clock Cycles (1S)
LED
Sample Smoke
Low Battery Warning Chirp
Horn
See Figure Below for Complete Horn Cycle
TIODLY
IO (Pin 2) as Output
Timing not same scale as above
IO Charge Dump
IO ( Pin 2) as Input
Horn
LED supressed in remote alarm mode
Start of horn temporal pattern is not synchronized to an external alarm
Horn pattern not self completing for external alarm,see timing below for complete horn cycle
Internal Clock
Notes:
1. Smoke is not sampled w hen the horn is active. Horn cycle is self completing in local alarm.
2. Low battery w arning chirp is suppressed in local or remote alarm
3. IO Dump active only in local alarm, inactive if external alarm
THON1 THOF1
THOF2
Complete Temporal Horn Pattern
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DS-RE46C122-060104
This datasheet contains PROPRIETARY and CONFIDENTIAL information.
RE46C122
CMOS Ionization Smoke Detector ASIC with Interconnect and Timer Mode
Preliminary Product Specification
R&E International
Timing Diagram (Timer Mode)
Oscillator
11mS
1.67S
Internal Clock
TSTART
TLOF3
LED
Outputs High Z
TSTROBE
TTPER
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DS-RE46C122-060104
This datasheet contains PROPRIETARY and CONFIDENTIAL information.
RE46C122
CMOS Ionization Smoke Detector ASIC with Interconnect and Timer Mode
Preliminary Product Specification
R&E International
R&E INTERNATIONAL, Inc. reserves the right to make changes without further notice to any products herein to improve
reliability, function or design.
R&E INTERNATIONAL, Inc. does not assume any liability arising out of the application or use of any product or circuit
described herein; neither does it convey any license under its patent rights, nor the rights of others.
R&E INTERNATIONAL, Inc. products are not authorized for use as critical components in life support devices or systems
without the express written approval of the President of R&E INTERNATIONAL, Inc. Life support devices or systems are
devices or systems which are intended for surgical implant into the body to support or sustain life, and whose failure to
perform, when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to
result in a significant injury to the user. A critical component is any component of a life support device or system whose
failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety
or effectiveness.
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DS-RE46C122-060104
This datasheet contains PROPRIETARY and CONFIDENTIAL information.