WAKE-UP TIMER IC PIN-SELECTABLE WAKE-UP TIMER IC S-35720 Series Rev.1.0_00 Power-on Detection Circuit In order for the power-on detection circuit to operate normally, raise the power supply voltage of the IC from 0.2 V or lower so that it reaches 1.8 V of the operation power supply voltage minimum value within 10 ms, as shown in Figure 9 . Within 10 ms 1.8 V (Operation power supply voltage min.) 0.2 V or lower 0 V *1*1. 0 V means that there is no potential difference between the VDD pin and the VSS pin of the S-35720 Series. Figure 9 How to Raise the Power Supply Voltage If the power supply voltage of the S-35720 Series cannot be raised under the above conditions, the power-on detection circuit may not operate normally and an oscillation may not start. In such case, perform the operations shown in _______ " 1. When power supply voltage is raised at RST pin = "L" " and " 2. When power supply voltage is raised at _______ RST pin = "H" ". _______ 1. When power supply voltage is raised at RST pin = "L" _______ _______ Set the RST pin to "L" until the power supply voltage reaches 1.8 V or higher. While the RST pin is set to "L", the _______ oscillation start signal becomes "H", and the crystal oscillation circuit normally oscillates. If the RST pin is set to "H" after the power supply voltage reaches 1.8 V, the oscillation start signal becomes "L" within 500 ms, and the oscillation status is maintained. _______ The current consumption increases by 30 μA typ. while the RST pin is set to "L". 10 ms 1.8 V (Operation power supply voltage min.) 0.2 V or lower 0 V *1 RST pin input Oscillation start signal *1. 0 V means that there is no potential difference between the VDD pin and the VSS pin of the S-35720 Series. _______ Figure 10 When Power Supply Voltage is Raised at RST Pin = "L" 10