RX630_15 Datasheet, PDF (140/156 Pages) Renesas Technology Corp – Renesas MCUs

RX630 Group
5. Electrical Characteristics
5.10 Battery Backup Function Characteristics
Table 5.29 Battery Backup Function Characteristics
Conditions: VCC = AVCC0 = VREFH = VCC_USB = 2.7 to 3.6 V, VREFH0 = 2.7 V to AVCC0, V_BATT = 2.3 to 3.6 V
VSS = AVSS0 = VREFL/VREFL0 = VSS_USB = 0 V
T_a = T_opr
Item
Symbol
Min.
Typ.
Max.
Unit
Test
Conditions
Voltage level for switching to battery backup
Lower-limit VBATT voltage for power supply switching due to
VCC voltage drop
V_DETBATT
V_BATTSW
VCC-off period for starting power supply switching
t_VOFFBATT
2.50
2.70
200
2.60
—
—
2.70
—
—
V
Figure 5.45
μs
Note: The VCC-off period for starting power supply switching indicates the period in which VCC is below the minimum value of the
voltage level for switching to battery backup (V_DETBATT).
VCC
V_DETBATT
t_VOFFBATT
VCC
Return from battery
backup not possible
VCC voltage
guaranteed range
VBATT
V_BATTSW
VBATT
Switching prohibited
Backup power
area
VCC supply
VBATT supply
VBATT
Switching prohibited
VCC supply
VBATT voltage
guaranteed range
Note. _{When VCC falls below VDETBATT, the voltage for switching to battery backup, make sure that VCC does not rise}
above V_DETBATT during the VCC-off period required to start switching between power supplies.
The VBATT voltage when the supplied power source switches from Vcc to V_BATT should not be lower than V_BATTSW,
the lower-limit VBATT voltage for switching between power supplies due to a drop in the VCC voltage.
Figure 5.45 Battery Backup Function Characteristics
R01DS0060EJ0160 Rev.1.60
May 19, 2014
Page 140 of 154