MCZ145012EG/R2 FREESCALE [Freescale Semiconductor, Inc], MCZ145012EG/R2 Datasheet - Page 11

• Manufacturer Part Number: MCZ145012EG/R2
• Description: Photoelectric Smoke Detector IC with I/O and Temporal Pattern Horn Driver
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

Sensors
Freescale Semiconductor
detectors, the MC145012 can be placed in a calibration
mode. In this mode, certain device pins are controlled/
reconfigured as shown in
calibration mode, Pin 16 (Test) must be pulled below the V
Table 5. Configuration of Pins in the Calibration Mode
I/O
Low-Supply Trip
Feedback
OSC
Silver
Brass
NOTES: Illustration is bottom view of layout using a DIP. Top view for SOIC layout is mirror image.
To facilitate checking the sensitivity and calibrating smoke
Description
Optional potentiometer R9 is not included.
Drawing is not to scale.
Leads on D2, R11, R8, and R10 and their associated traces must be kept as short as possible. This practice minimizes noise
Pin 3 must be decoupled from all other traces.
pick up.
Pin
15
10
12
7
9
8
Table
Disabled as an output. Forcing this pin high places the photo amp output on Pin 1 or 2, as determined by Low-
Supply Trip. The amp's output appears as pulses and is referenced to V
If the I/O pin is high, Pin 15 controls which gain capacitor is used. Low: normal gain, amp output on Pin 1. High:
supervisory gain, amp output on Pin 2.
Driving this input high enables hysteresis (10% gain increase) in the photo amp; Pin 15 must be low.
Driving this input high brings the internal clock high. Driving the input low brings the internal clock low. If
desired, the RC network for the oscillator may be left intact; this allows the oscillator to run similar to the normal
mode of operation.
This pin becomes the smoke comparator output. When the OSC pin is toggling, positive pulses indicate that
smoke has been detected. A static low level indicates no smoke.
This pin becomes the smoke integrator output. That is, 2 consecutive smoke detections are required for “on”
(static high level) and 2 consecutive no-detections for “off” (static low level).
5. To place the part in the
Additional Traces
Do Not Run Any
In This Region
Figure 9. Recommended PCB Layout
Pin 16
Pin 9
CALIBRATION
SS
PIN 8
Pin 1
pin with 100 µA continuously drawn out of the pin for at least
one cycle on the OSC pin. To exit this mode, the Test pin is
floated for at least one OSC cycle.
to one for every OSC cycle. Also, Strobe is always active low.
C1
In the calibration mode, the IRED pulse rate is increased
MOUNTED IN
CHAMBER
R11
R14
D2
Comment
R8
DD
etc.
MC145012
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