RV5C387A_03 Datasheet, PDF (43/49 Pages) RICOH electronics devices division – I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC WITH VOLTAGE MONITORING FUNCTION

RV5C387A
6.2 Connection of INTRA, INTRB or INTRC Pin
The INTRA, INTRB or INTRC pin follows the N-channel open drain output logic and contains no protective diode on
the power supply side. As such, it can be connected to a pull-up resistor of up to 5.5 volts regardless of supply
voltage.
RV5C387A
INTRA or INTRB or INTRC
OSCIN
OSCOUT
VDD
VSS
System power supply
A
B ^*1
Backup power supply
32.768kHz
*1) Depending on whether the INTRA, INTRB or INTRC pin is to be
used during battery backup, it should be connected to a pull-up
resistor at the following different positions:
1) Position A in the left diagram when it is not to be used during
battery backup.
2) Position B in the left diagram when it is to be used during
battery backup.
6.3 Connection of 32KOUT Pin
The 32KOUT pin follows the Nch. open drain output and contains no protective diode on the power supply side. As
such, it can be connected to a device with a supply voltage of up to 5.5 volts regardless of supply voltage, provided
that such connection involves considerations for the supply current requirements of a pull-up resistor, which can be
roughly calculated by the following equation:
I=0.5×(VDD or VCC)/ Rp
RV5C387A
32KOUT
OSCIN
OSCOUT
VDD
VSS
System power supply (VCC)
Rp
A
B ^*1
32.768kHz
Backup battery
(VDD)
*1) Depending on whether the 32KOUT pin is to be used during
battery backup, it should be connected to a pull-up resistor at
the following different positions:
1) Position A in the left diagram when it is not to be used during
battery backup.
2) Position B in the left diagram when it is to be used during
battery backup.
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