PCF2129AT NXP [NXP Semiconductors], PCF2129AT Datasheet - Page 17

• Manufacturer Part Number: PCF2129AT
• Description: Integrated RTC, TCXO and quartz crystal
• Manufacturer: NXP [NXP Semiconductors]

NXP Semiconductors
PCF2129A_1
Product data sheet
8.5.2 Battery backup supply
The internal power supply (available on pin BBS) is equal to V
assured that there are decoupling capacitors on the pins V
The V
on the selected battery switch-over function mode:
Table 14.
Battery switch-over function mode
standard
direct switching
disabled
Fig 6.
Fig 7.
V
BBS
BBS
(mV)
−200
−400
−600
−800
− V
Battery switch-over circuit, simplified block diagram
Typical driving capability of V
current I
voltage on the output pin BBS is equal to the internal power supply and depends
0
DD
Output pin BBS
0
V
V
th(sw)bat
th(sw)bat
V
V
BAT
DD
BBS
Rev. 01 — 13 January 2010
comparators
V
V
CC
CC
2
LOGIC
BBS
Conditions
V
V
V
V
only V
V
DD
DD
DD
DD
BAT
logic
: (V
> V
< V
> V
< V
must be put to ground
4
BBS
DD
V
Integrated RTC, TCXO and quartz crystal
BAT
BAT
BAT
BAT
DD(int)
V
available,
V
BAT
− V
DD
V
V
OR V
AND V
DD
DD
DD
= 3 V
= 2 V
) with respect to the output load
DD
DD
switches
V
V
> V
DD(int)
DD(int)
DD
< V
th(sw)bat
6
, V
th(sw)bat
DD
BAT
or V
I
BBS
, and BBS.
(internal
power supply)
PCF2129A
V
BAT
(mA)
001aag061
BBS
© NXP B.V. 2010. All rights reserved.
001aaj431
. It has to be
V
V
V
V
V
V
BBS
DD
BAT
DD
BAT
DD
8
equals
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