Rx5C348A/B
ꢁ
Connection of /INTR and 32KOUT Pin
The /INTR 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 5.5v regardless of supply voltage.
The 32KOUT pin follows the N-channel open drain output logic, too. However, it contains protective diode on the
power supply side. As such, it cannot be connected to a pull-up resistor over VDD+0.3v. 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
System power supply
(VDD)
*1) Depending on whether the /INTR or 32KOUT
pins are 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.
A
/INTR or 32KOUT
*1)
B
OSCIN
Backup power supply
(VCC)
32768Hz
OSCOUT
VSB
VSS
ꢁ
Connection of CE Pin
Connection of the CE pin requires the following considerations:
1) The CE pin is configured to enable the oscillation halt sensing circuit only when driven low. As such, it
should be driven low or open at power-on from 0v.
2) The CE pin should also be driven low or open immediately upon the host going down (see "P.25 ꢁ
Considerations in Reading and Writing Time Data under special condition").
SCLK
I/O
CONTROL
SI
Lower limit operating
voltage for the CPU
SO
VDD
Backup power supply
CE
CE
0.2×VDD
Min.0µs
Min.0µs
Min.0µs
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Rev.2.01
- 38 -
RICOH [ RICOH ELECTRONICS DEVICES DIVISION ]
