EM78P447S
OTP ROM
4.11 Residue-Voltage Protection
When battery is replaced, device power (Vdd) is taken off but residue-voltage remains. The residue-voltage may trips
below Vdd minimum, but not to zero. This condition may cause a poor power on reset. Fig.16 and Fig.17 show how to build
the residue-voltage protection circuit.
Vdd
Vdd
33K
EM78P447N
Q1
10K
/RESET
40K
1N4684
Fig.14 The Residue Voltage Protection Circuit 1
Vdd
Vdd
R1
EM78P447N
/RESET
Q1
R2
40K
Fig.15 The Residue Voltage Protection Circuit 2
This specification is subject to change without prior notice.
29
06.25.2003 (V1.1)