BL8509B Datasheet, PDF (6/10 Pages) SHANGHAI BELLING CO., LTD. – Ultra-small package High-precision Voltage Detector with delay

BL8509B
Directions for use：
1、 Please use this IC within the stated maximum ratings. Operation beyond these limits may cause degrading or
permanent damage to the device.
2、When a resistor is connected between the V_DD pin and the input with CMOS output configurations, oscillation may
occur as a result of voltage drops at R_IN if load current(I_OUT) exists.(refer to the Oscillation Description(1) below)
3、When a resistor is connected between the V_DD pin and the input with CMOS output configurations, oscillation may
occur as a result of through current at the time of voltage release even if load current(I_OUT) does not exist. (refer
to the Oscillation Description(2) below)
4、With a resistor connected between the V_DD and the input, detect and release voltage will rise as a result of the IC’s
supply current flowing through the V_DD pin.
5、In order to stabilize the IC’s operations, please ensure that V_DD pin’s input frequency’s rise and fall times are more
than several u Sec/V.
Oscillation Description：
1、 Output current oscillation with the CMOS output configuration
When the voltage applied at IN rises, release operations commence and the detector’s output voltage increase.
Load current(I_OUT) will flow at R_L. Because a voltage drop(R_IN*I_OUT) is produces at the R_IN resistor, located
between the input(IN) and the V_DD pin. The load current will flow via the IC’s pin. The voltage drop will also lead to
a fall in the voltage level at the V_DD pin. When the V_DD pin voltage level falls below the detect voltage level, detect
operations will commence. Fllowing detect operations, load current flow will cease and since voltage drop at R_IN
will disapper, the voltage level at the V_DD pin will rise and release operations will begin over again. Oscillation
may occur with this “release-detect-release” repetition. Further, this condition will also appear via means of a
similar mechanism during detect operations.
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