HA16117F Datasheet, PDF (27/31 Pages) Hitachi Semiconductor – CMOS Watchdog Timer

HA16117F Series
P-RUN Input Frequency vs. K (Tadj constant)
1M
100 k
Ta = 25°C
K= ^R2
R1 + R2
10 k
1k
MPU system normal
100
10
MPU system abnormal
1
0.55 0.6
0.7
0.8
Tadj constant K
5V
Pulse
generator
5V
0V
duty 50%
0.01 µ
R₁
V_CC
Tadj
R₂
P-RUN ACC
C_F
GND
C_R
RES
0.1 µ
Test circuit
Oscilloscope
K = ^R2
R₁ + R₂
Notes: 1. Normal detection is assumed when RES is not output.
2. The figure at left is for a constant P-RUN frequency.
P-RUN High Threshold Frequency vs. C_F Capacitance
10 M
Ta = 25°C
MPU system abnormal
1M
5V
Pulse
generator
V_CC
Tadj
P-RUN ACC
C_F
GND
C_R
RES
510 k
750 k
100 k
C_F
C_R
0 V to 5 V duty 50%
Oscilloscope
MPU system normal
Test circuit
Notes: 1. Normal detection is assumed when RES is not output.
10 k
500 p 1000 p
0.01 µ 0.03 µ
2. The figure at left is for a constant P-RUN frequency.
External capacitance C_F (F)
27