BD4728G Rohm, BD4728G Datasheet - Page 5

• Manufacturer Part Number: BD4728G
• Description: RESET IC
• Manufacturer: Rohm

Voltage detectors
Delay time can be set by capacitor CL and resistance RL connected to the output pin as shown below.
CL is charged by RL when Vcc is rising. The delay time caused by charging is determined by the time constant of CL, RL
and the threshold voltage of RESET pin. Voltage detector IC discharges CL forcedly when Vcc is falling. The delay time
of RESET single is determined by adding the delay time of sing le Voltage detector IC to each time.
BD47XXG
For both BD47xxG series detection voltage and release voltage is threshold voltage. When voltage applied to
reaches each threshold voltage, output goes “H”→”L” or “L”→”H”.
Some hysteresis is given such a way that the release voltage is the detection voltage +50mV(Typ), and as toprevent
fluctuation in output . When input is equal to or more than the release voltage, output is in “H” mode.
When input is gradually decreased from this mode, output turns “L” in the detection voltage.
When input is equal to or less than the detection voltage, output is in “L” mode. When input is gradually increased from
this mode, output turns “H” in the release voltage.
Input of 0.85V and more is necessary to operate circuit completely , the output becomes inconsistent if the input is equal
to or lower than the operating limit voltage.
V
Setting of the RESET signal delay time
Operating explanation
A
GND
Vcc
Fig.7 Current consumption
Vout
10 F
V
CC
BD4729G
R
C
GND
L
L
V
OUT
RESET
GND
V
DD
NC
CPU
Micro-controller
V
RESET
(=VOUT)
Fig.9
VCC
Fig.8 I/O characteristic
VS+ΔVS
VCC
VS
0V
VOH
VOL
10 F
V
CC
BD4729G
R 4.7k
GND
T
PLH
V
OUT
BD47××G series
T
PHL
T
PLH
5/8
input