Document
BL59A66 datasheet
1. Introduction:
The BL59A66 is a low-current BiCMOS circuit providing all of the features for a photoelectric type smoke detector. BL59A66 can be used in conjunction with an infrared photoelectric chamber to sense scattered light from smoke particles. Special features are incorporated in the design to facilitate calibration and testing of the finished detector.
2.1 Applied Area:
Photoelectric Type Smoke Detector System。
2.2 Features:
2.2.1 6 V to 12 V Operating Voltage Range 2.2.2 Internal Timer & Control for Reduced Sensitivity 2.2.3 Supply Voltage current:0~10uA 2.2.4 Operating Temperature Range:-25~75℃ 2.2.5 Power-ON Reset 2.2.6 ESD and Latch-up Protection Circuitry on All Pins 2.2.7 Piezoelectric Horn Driver 2.2.8 Interconnect Up to 50 Detectors 2.2.9 Continuous Modulated Tone Output For a Local or Remote Alarm Condition
2.3 FUNCTIONAL BLOCK DIAGRAM
2.4 Pin Description
2.5 Pin function
Pin No. Pin symbol
1 ,2 C1 , C2
3 DETECT
4 STROBE
5 ,14
Vdd , VSS
Input/O utput
Input Output
Function Description
Exterior capacitor connected to the pins Input to the photo amplifier Regulated voltage Output Power/Gnd
A capacitor connected to the pins determines the gain of the photo amplifier.
This pin connects the cathode of the photo diode. The photo diode is operated at zero bias.
The pin is the Regulated voltage Output. The value is Vdd-5V.
Power supply
6 IRED
Output
7 I/O
8 ,9 BRASS,
Output
SILVER
10 FEEDBACK Inuput
11 LED
Output
12 OSC 13 R1
15 LS SET
Input Intput
16 TEST
Input
3. Circuit characteristic:
Signal output
Piezoelectric Transducer Output Piezoelectric Transducer Input Signal output
OSC Input Exterior capacitor and resistor connected to the pins Low sensitive set
Test Input
This pin is a output, which provides a pulsed base current for the external npn transistor, which drives the IR emitter.
A connection at this pin allows multiple smoke detectors (less than 50) to be interconnected.
These TWO pins are used in conjunction with a piezoelectric transducer.
The pin is used in conjunction with a piezoelectric transducer feedback electrode.
This open-drain NMOS output is used to directly drive a 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 exterior capacitor and resistor, sets the internal clock low time.
The pin connects with exterior capacitor and resistor, sets the internal IRED output pulse period.
This input pin serves two purposes in normal operation. This reference is established by a resistive divider between VDD and STROBE. This allows the detector to have a different sensitivity set point during the timer mode.
This pin has an internal pull-down device and is used to manually invoke two test modes and a Timer Mode.
3.1 The gain is determined by exterior capacitor C1 and C2. A capacitor connected to C2 determines the gain of
the photo amplifier during standby. A typical value for this low-gain mode is 4700 pF but should be selected
based on a specific photo chamber and the desired level of sensitivity to smoke. AV= 1+(C2/10) where C2 is in
pF. This gain increases by a nominal 10% after a local alarm is detected (three consecutive detections).
3.2 I/O pin allows multiple smoke detectors to be interconnected. If a local smoke condition occurs, this pin is
driven high. As an input, this pin is sampled nominally every 1.35 seconds during standby. Any local alarm
condition causes I/O to be ignored as an input.
3.3 LED pin is a output pin, which is used to directly drive a visible LED. The load for the low-battery test is
applied to this output. The low-battery test does not occur coincident with any other test or alarm signal. The
LED also indicates detector status as follows (with component values as in the typical application, all times
nominal):
Standby - Pulses every 43 seconds.
Local Smoke - Pulses every 0.67 second.
Remote Alarm - No pulses.
Test Mode - Pulses every 0.67 second.
Timer Mode - Pulses every 10 seconds.
4. Circuit characteristic parameter:
4.1 Absolute Maximum Rating
(Voltages are referenced to VSS)
Symbol VDD
VIN IIN TA Tstg
TL
Parameter Supply Voltage
Input Voltage
Input Current Operating Temperature
Storage Temperature
Welding Temperature
Range -0.5~+15 -0.3~VDD+0.3 10 -25 ~ +75 -55 ~ +125 260
4.2 DC characteristic (Voltages are referenced to VSS)
Symbol VDD VTH
Parameter Supply Voltage Range Low VDD(th) threshold
Conditions
IDD Operating Supply Current
Standby
iDD Operating Supply Current VIL Low-Level Input Voltage
I/O Feedback Test LS SET VIH High-Level Input Voltage
Strobe on IRED off
I/O Feedback Test LS SET IIH Input Leakage High
C1,C2 Detect, Feedback, OSC
Vin=VDD,Strobe active Pin 12=Vdd Vin=VDD
IIL Input Leakage Low C1, C2, Detect
Feedback, OSC LS SET, TEST
Vin=VST,Strobe active, Pin 12=Vdd Vin=VSS Vin=VSS
IIN Input Pull-Down Current
Test, LS SET I/O
Vin=VDD No Local Alarm, Vin=VDD
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