BL59A65 Datasheet, PDF (3/11 Pages) SHANGHAI BELLING CO., LTD. – Photo Smoke Detector Control IC with hush

BL59A65
12
OSC
13
R1
15
LS SET
16
TEST
Input
Intput
Input
OSC Input
External capacitor
and resistor
connected to the pins
Low sensitive set
Test Input
visible LED. The LED also indicates detector status as
follows (with component values as in the typical
application, all times nominal)
The pin connects with external capacitor and resistor,
sets the internal clock low time.
The pin connects with external capacitor and resistor,
sets the internal clock high time, which is also IRED
pulse width.
This input pin serves two purposes in normal operation:
serves as an enable for the internal 10-minutes
(nominal) timer and also as the reference (set by
external resistor divider between VDD and STROBE)
for the smoke comparator during the timer mode. This
allows the detector to have a different sensitivity set
point during the timer mode. If the timer mode is not
used, this pin can be left open or connected to Vss,
which disables this mode.
This pin has an internal pull-down device and is used to
manually invoke Test Mode and Timer Mode. High
logic level on this pin initiates Push-to-Test Mode (Av =
1 + (C1/10) where C1 is in pF.). When push-button is
released, the input returns to Vss due to the pull down.
This high-to-low transition on the pin also resets and
starts the 10 minutes hush timer (Timer Mode).
FUNCTIONAL BLOCK DIAGRAM
Fig.2 Functional Block Diagram
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