EM78P447N

8-Bit Microcontroller with 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

EM78P447N

/RESET

Vdd

33K

Q1

10K

40K1N4684

Fig. 14 The Residue Voltage Protection Circuit 1

Vdd

EM78P447N

/RESET

Vdd

R1

Q1

40KR2

Fig. 15 The Residue Voltage Protection Circuit 2

Product Specification (V1.1) 03.30.2005

29

(This specification is subject to change without further notice)

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Image 33
IBM EM78P447N manual Residue-Voltage Protection, Reset