Phytec phyCORE-i.MX31, Hardware Manual

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phyCOREi.MX31
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PHYTEC Messtechnik GmbH 2007 L-700e_0
5 Real Time Clock U18 / SRAM U19 Battery
The connection of a battery is not essential to the functioning of the phyCORE-i.MX31. The battery,
interfaced as voltage supply signal x_VBAT through X1 pin 6C on the phyCORE-connector, provides
power to the I²C Real Time Clock U18 (RTC8564JE) and the low power SRAM U19. This provides a
means of time/memory keeping in the absence of power at the VCC_3V3 pins while drawing minimal
power from the battery.
The x_VBAT (2.0V < x_VBAT < VCC_3V3) input operating limits are listed in Table 4 below.
Table 4: x_VBAT operating limits
M
IN
T
YP
M
AX
U
NITS
x_VBAT 2.0 3.1V 3.3V V
Caution:
Operation with x_VBAT greater than VCC_3V3 could cause unintentional discharge of the battery.
If you choose not to use a battery with the phyCORE-i.MX31 then x_VBAT should be connected to
VCC_3V3 external to the phyCORE-i.MX31.
See section 11 Technical Specifications for battery power consumption.