Energy-efficient, autonomous timing circuit featuring time stamp, battery back-up, two
alarms, and resolution up to 1/100 s.
NXP RTC
PCF85263
RTC with battery back-up switch and
time stamp
KEY FEATURES
` Multiple operating modes
- Clock (seconds to 99 years)
- Stopwatch or elapsed-time counter (1/100 s to 999 999 h)
- WatchDog in parallel
` Battery input voltage can be lower or higher than V
DD
` Meets UL requirements
` Time-stamp input, three time-stamp registers
` Two independent alarms
` Electronic frequency tuning via command
` Large clock operating voltage range (0.9 to 5.5 V)
` Ideal for battery-backed operation (I
DD
= ~0.27 µA)
` 400 kHz two-line I
2
C-bus interface (at V
DD
= 1.8 to 5.5 V)
` SO8, TSSOP8, TSSOP10, and tiny DFN2626 package
APPLICATIONS
` Printers, copiers
` Electronic metering
` TVs, Blu-Ray players, projectors, etc.
` White goods
` Digital cameras
` Accurate, high-duration timers
` Data loggers
The NXP PCF85263 is a CMOS real-time clock (RTC) and
calendar, optimized for low power consumption, that switches
automatically to battery power when main power is lost.
The PCF85263 can be configured as a stopwatch (or elapsed-
time counter) with a resolution of up to 1/100 s. Three time
stamps make it easy to register special events, and the
device can also register tamper detection or time of battery
switchover.
A sophisticated battery backup circuit improves power
efficiency. The circuit makes it possible to use a battery with a
nominal voltage that is higher or lower than the regular supply
voltage. For example, in a system that uses a V
DD
of 2.5 V, a
lithium battery of 3 V can be used as a backup.
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© 2014 NXP Semiconductors N.V.
All rights reserved. Reproduction in whole or in part is prohibited without the prior written consent of the copyright owner. The
information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and
may be changed without notice. No liability will be accepted by the publisher for any consequence of its use. Publication thereof
does not convey nor imply any license under patent- or other industrial or intellectual property rights.
Date of release: August 2014
Document order number: 9397 750 17592
Printed in the Netherlands
The PCF85263 can be used to perform standard RTC
functions, such as tracking the actual time and data or acting
as a reference timer. To support power management, the
PCF85263 can be used to wake the microcontroller from
hibernation mode, and in systems that use a PLL, it can serve
as a system reference clock for the PLL input. The PCF85263
can also be used as a WatchDog timer, or as an activation
timer to start measurements or initiate other functions.
Interrupt selection: at every second, minute, or hour and up
to two alarms on two independent outputs. The designer can
choose between a permanent or a pulse interrupt signal or one
interrupt and a time-stamp input.
For compensating the quartz frequency tolerance, a
dedicated offset register can be programed.
Full featured versions are available in TSSOP10 and lead less
package DFN2626-10 package. Versions without time stamp
pin are available in 8 pin packages SO8 and TSSOP8. All are
equipped with an I
2
C Fast-Mode (FM) interface.
Versions in a leadless package and equipped with an SPI
(PCF85263B) interface are available on request.
DEMO BOARD
The PCF85263 is supported by the demo board OM13510,
equipped with battery backup and a jumper to select the RTC.
The board is shipped ready to use, with a quartz. In order to
start, connect the power supply and use the serial interface to
initiate communications for setting the actual time.
PCF85263A block diagram
PCF85263A
MASTER
TRANSMITTER/
RECEIVER
OSCI
OSCO
VSS
SDA
R
aaa-010565
R
SCLSDA
(I
2
C-bus)
SCL
SDA
SCL
INTAVBAT
V
DD
V
DD
100 nF
R: pull-up resisto
r
R =
t
r
C
b
CLK
VDD
TS
100 nF
PCF85263A application diagram
PCF85263 evaluation board I
2
C (OM13510)
*Released on request ** RTC sister family with additional 64 Byte battery buffered RAM
Product number PCF85263AT PCF85263ATT PCF85262ATT1 PCF85263ATL PCF85263B* PCF85363 family**
Interface FM I²C-bus FM I²C-bus FM I²C-bus FM I²C-bus SPI I²C/SPI
Battery switch, interrupt / CLK output X X X X X X
Time-stamp input, separate CLK output - - X X X (X)
Package SO8 TSSOP8 TSSOP10 DFN2626-10 DFN2626-10, TSSOP10
DFN2626-10,
TSSOP8,10
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