PCF2129AT NXP [NXP Semiconductors], PCF2129AT Datasheet - Page 16

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

NXP Semiconductors
PCF2129A_1
Product data sheet
8.5.1.3 Battery switch-over disabled: only one power supply (V
8.5.1.4 Battery switch-over architecture
The direct switching mode is useful in systems where V
The direct switching mode is not recommended if the V
(e.g. V
reduced compared to the standard mode because the monitoring of V
not performed.
When the battery switch-over function is disabled:
The architecture of the battery switch-over circuit is shown in
Fig 5.
•
•
•
•
V
DD
V
The power supply is applied on the V
The V
The internal power supply, available at the output pin BBS, is equal to V
The battery flag (BF) is always logic 0
(= 2.5 V)
th(sw)bat
(= 0 V)
DD
V
V
INT
BAT
DD
BF
Battery switch-over behavior in direct switching mode with bit BIE logic 1
(enabled)
= 3.3 V, V
BAT
backup battery operation
pin must be connected to ground
V
BAT
BBS
Rev. 01 — 13 January 2010
≥ 3.0 V). In direct switching mode the power consumption is
internal power supply (= V
DD
pin
Integrated RTC, TCXO and quartz crystal
DD
DD
BBS
is higher than V
and V
DD
)
Figure
)
BAT
PCF2129A
values are similar
6.
DD
cleared via interface
© NXP B.V. 2010. All rights reserved.
and V
BAT
DD
at all times.
th(sw)bat
001aaj312
V
16 of 68
BBS
is