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EM78P312N
8-Bit Microcontroller
Product Specification
(V1.0) 10.03.2006 • 55
(This specification is subject to change without further notice)
EM78P809N
/RESET
Vdd
D
R
Rin
C
Fig. 5-34 External Power-Up Reset Circuit
5.18.2 Residue-Voltage Protection
When battery is replaced, device power (VDD) is taken off but residue-voltage remains.
The residue-voltage may trip below V
DD minimum, but not to zero. This condition may
cause a poor power-on reset. Fig.35 and Fig. 36 show how to build the residue-voltage
protection circuit.
EM78P809N
/RESET
Vdd
40K
Q1
1N4684
10K
33K
Vdd
Fig. 5-35 Residue Voltage Protection Circuit 1
Q1
R2
R1
40K
/RESET
EM78P809N
Vdd
Vdd
Fig. 5-36 Residue Voltage Protection Circuit 2
EM78P312N
EM78P312N
EM78P312N