em78f644nso28s ELAN Microelectronics Corp, em78f644nso28s Datasheet - Page 165

• Manufacturer Part Number: em78f644nso28s
• Description: Flash Series 8-bit Microcontroller
• Manufacturer: ELAN Microelectronics Corp

Product Specification (V1.0) 05.05.2010
(This specification is subject to change without further notice)
6.18 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. Figures 6-30a and 6-30b below show how to
accomplish a proper residue-voltage protection circuit.
Figure 6-30a Circuit 1 for the Residue Voltage Protection
Figure 6-30b Circuit 2 for the Residue Voltage Protection
/RESET
/RESET
Vdd
Vdd
40K
40K
Q1
Q1
EM78F648/644/642/641/548/544/542/541N
1N4684
10K
33K
R1
R2
8-Bit Microcontroller
Vdd
Vdd
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