LC87F1M16A Datasheet, PDF (31/32 Pages) Sanyo Semicon Device – 8-bit 1-chip Microcontroller with Full-Speed USB

LC87F1M16A
(a)
(b)
VDD
Reset unknown
area (POUKS)
RES
Reset period
100μs or longer
POR release voltage
(PORRL)
Reset period
Figure 11 Example of POR Only (LVD Deselected) Mode Waveforms (at Reset Pin with RRES Pull-up Resistor Only)
• The POR function generates a reset only when the power voltage goes up from the VSS level.
• No stable reset will be generated if power is turned on again when the power level does not go down to the VSS level
as shown in (a). If such a case is anticipated, use the LVD function together with the POR function as shown below or
implement an external reset circuit.
• A reset is generated only when the power level goes down to the VSS level as shown in (b) and power is turned on
again after this condition continues for 100μs or longer.
LVD hysteresis width
(LVHYS)
LVD release voltage
(LVDET+LVHYS)
VDD
Reset unknown area
(LVUKS)
RES
Reset period
Reset period
Reset period
LVD reset voltage
(LVDET)
Figure 12 Example of POR + LVD Mode Waveforms (at Reset Pin with RRES Pull-up Resistor Only)
• Reset are generated both when power is turned on and when the power level lowers.
• A hysteresis width (LVHYS) is provided to prevent the repetitions of reset release and entry cycles near the detection
level.
VDD
LVD release voltage
LVD detect voltage
VSS
TLVDW
LVDET-0.5V
Figure 13 Minimum Low Voltage Detection Width (Example of Voltage Sag/Fluctuation Waveform)
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