Panasonic DP-3000 - Page 28

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2. Reset Circuit
This circuit consists of IC301 (PST575E) and peripheral circuit. This circuit always watches 5V. Output
of this circuit (nRST) is set that if 5V falls below setting level (3.9V). When the 5V rises above voltage,
the reset signal is canceled after a delay of approximately 20 ms. After cancelling, software is started
by CPU.
IC301
PST575E
R321
Q303
C305
R320
R105
C103
1
2
3
4
IC101
CPU
pLPRST
Reset Circuit
Vdd
5V
3.9V
td
td
td=20ms
Reset Signal Timing Chart