HA16103 Datasheet, PDF (6/21 Pages) Hitachi Semiconductor – Watchdog Timer

HA16103 FPJ/FPK
Power-On Reset Function
The system contains the power-on reset function required when a microcomputer is turned on.
The reset period may be set with external components R_R and C_R. Equation 2 specifies how to determine
the reset period (ton) and figure 3 shows the characteristic of the circuit.
HA16103
RES
R_R C_R
ton = 0.46 x C_R x R _Rx Vout(s) ⋅ ⋅ ⋅ ⋅ Equation 2
R_R: Ω
200 m
180 m
(Ta = 25°C)
V_CC = 12 V
160 m
140 m
C_R = 0.22 µF
120 m
100 m
80 m
60 m
C_R = 0.1 µF
40 m
20 m
C_R = 0.047 µF
0
100 k
200 k
Resistance R_R (Ω)
500 k
Figure 3 Characteristic of Power-On Reset Circuit
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