Datasheet

PCF2129 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2014. All rights reserved.
Product data sheet Rev. 7 — 19 December 2014 18 of 86
NXP Semiconductors
PCF2129
Accurate RTC with integrated quartz crystal for industrial applications
8.5.1.1 Standard mode
If V
DD
> V
BAT
OR V
DD
>V
th(sw)bat
: V
oper(int)
is at V
DD
potential.
If V
DD
< V
BAT
AND V
DD
<V
th(sw)bat
: V
oper(int)
is at V
BAT
potential.
V
th(sw)bat
is the battery switch threshold voltage. Typical value is 2.5 V. In standard mode, the
battery switch-over works only for V
DD
> 2.5 V.
V
DD
may be lower than V
BAT
(for example V
DD
=3V, V
BAT
=4.1V).
Fig 6. Battery switch-over behavior in standard mode with bit BIE set logic 1 (enabled)
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