NXP Semiconductors
15. Application information
PCF2123
SPI Real time clock/calendar
1F
supercapacitor
100 nF
VDD
OSCI
OSCO
CLKOE CLKOUT
PCF2123
VSS
INT
CE
SCL
SDI
SDO
001aai557
A 1 farad super capacitor combined with a low VF diode can be used as a standby or back-up
supply. With the RTC in its minimum power configuration i.e. timer off and CLKOUT off, the RTC
may operate for weeks.
Fig 30. Typical application diagram
PCF2123
Product data sheet
All information provided in this document is subject to legal disclaimers.
Rev. 6 — 15 July 2013
© NXP B.V. 2013. All rights reserved.
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