PCF2127AT/1,518 NXP Semiconductors, PCF2127AT/1,518 Datasheet - Page 18
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PCF2127AT/1,518
Manufacturer Part Number
PCF2127AT/1,518
Description
IC RTC/CALENDAR TCXO QTZ 20SOIC
Manufacturer
NXP Semiconductors
Type
Clock/Calendar/Alarmr
Datasheet
1.PCF2127AT1518.pdf
(80 pages)
Specifications of PCF2127AT/1,518
Package / Case
20-SOIC (0.300", 7.50mm Width)
Time Format
HH:MM:SS (12/24 hr)
Memory Size
512B
Date Format
YY-MM-DD-dd
Interface
I²C, 2-Wire Serial
Voltage - Supply
1.8 V ~ 4.2 V
Operating Temperature
-40°C ~ 85°C
Mounting Type
Surface Mount
Function
Serial Clock, Timestamp, Timekeeper, Watchdog, Alarm, Calendar, Timer, Timer Interrupt
Rtc Memory Size
512 bytes
Supply Voltage (max)
4.2 V
Supply Voltage (min)
1.8 V
Mounting Style
SMD/SMT
Rtc Bus Interface
I2C
Supply Current
2600 nA
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
NXP Semiconductors
PCF2127A_2
Product data sheet
8.6.1.1 Standard mode
8.6.1 Battery switch-over function
The PCF2127A has a backup battery switch-over circuit which monitors the main power
supply V
condition is detected.
One of two operation modes can be selected:
V
When a power failure condition occurs and the power supply switches to the battery the
following sequence occurs:
The interface is disabled in battery backup operation:
If V
If V
1. The battery switch flag BF (register Control_3) is set logic 1.
2. An interrupt is generated if the control bit BIE (register Control_3) is enabled
3. If the control bit BTSE (register Control_3) is logic 1, the timestamp registers store the
4. The battery switch flag BF is cleared via the interface; it must be cleared to clear the
th(sw)bat
•
•
•
•
DD
DD
Standard mode: the power failure condition happens when:
V
Direct switching mode: the power failure condition happens when V
Direct switching from V
(see
time and date when the battery switch occurred (see
interrupt.
Interface inputs are not recognized, preventing extraneous data being written to the
device
Interface outputs are high-impedance
DD
> V
< V
DD
< V
is the battery switch threshold voltage. Typical value is 2.5 V.
Section
BAT
BAT
and automatically switches to the backup battery when a power failure
BAT
OR V
AND V
All information provided in this document is subject to legal disclaimers.
AND V
8.13.7).
DD
DD
> V
DD
< V
Rev. 02 — 7 May 2010
th(sw)bat
< V
DD
th(sw)bat
th(sw)bat
to V
the internal power supply is V
BAT
the internal power supply is V
without requiring V
Integrated RTC, TCXO and quartz crystal
DD
Section
to drop below V
DD
BAT
8.12.4).
.
PCF2127A
.
© NXP B.V. 2010. All rights reserved.
DD
th(sw)bat
< V
BAT
18 of 80
.