WAKE-UP TIMER IC

PROGRAMMABLE WAKE-UP TIMER IC

S-35710 Series

21



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 27.

Within 10 ms

1.8 V

(Operation power

supply voltage min.)

0 V

*1

0.2 V or lower

*1. 0 V means that there is no potential difference between the VDD pin and the VSS pin of the S-35710 Series.

Figure 27 How to Raise Power Supply Voltage

If the power supply voltage of the S-35710 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 as mentioned below while the RST

_______

pin is set to "L".

• S-35710C01I (without pull-up resistor):

1.7

μA typ.

• S-35710B01I (with pull-up resistor):

30

μA typ.

0.2 V or lower

RST pin input

Oscillation start signal

10 ms

1.8 V

(Operation power supply voltage min.)

*1. 0 V means that there is no potential difference between the VDD pin and the VSS pin of the S-35710 Series.

Figure 28 When Power Supply Voltage is Raised at RST

_______

Pin = "L"