Preliminary
CBC34123 EnerChip™ RTC
SPI Real-Time Clock/Calendar with Integrated Backup Power
Features
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Integrated rechargeable solid state battery with
power-fail detect and automatic switchover,
pro-
viding greater than 30 hours of RTC backup
Smallest commercially available RTC with inte-
grated backup power in compact 5mm x 5mm
1.4mm QFN package
Temperature compensated charge control
Integrated EnerChip™ recharged at VDD > 2.5V
SMT assembly - lead-free reflow solder tolerant
Real time clock provides year, month, day, week-
day, hours, minutes, and seconds based on a
32.768 kHz quartz crystal
Resolution: seconds to years
Watchdog functionality
Freely programmable timer and alarm with inter-
rupt capability
3-line SPI-bus with separate, but combinable
data input and output
Integrated oscillator load capacitors for C
L
= 7 pF
Internal Power-On Reset (POR)
Open-drain interrupt and clock output pins
Programmable offset register for frequency
adjustment
Eco-friendly, RoHS compliant - tested
5mm x 5mm x 1.4mm 16-QFN Package
General Description
The EnerChip RTC CBC34123-M5C combines a
Real-Time Clock (RTC) and calendar optimized
for low power applications with an integrated
rechargeable solid state backup battery and all power
management functions. The EnerChip RTC ensures
a seamless transition from main power to backup
power in the event of power loss. The integrated
power management circuit ensures thousands of
charge-discharge cycles from the integrated EnerChip
and manages battery charging, discharge cutoff,
power switchover, and temperature compensation
to maximize the service life of the device. The
CBC34123 provides greater than 30 hours of backup
time in the event main power is interrupted. Typical
blackout times are less than 4 hours. The EnerChip
has extremely low self-discharge, recharges quickly, is
non-flammable, and RoHS-compliant. The EnerChip is
charged automatically anytime VDD is above 2.5V.
Data is transferred serially via a Serial Peripheral
Interface (SPI-bus) with a maximum data rate of 6.25
Mbit/s. Alarm and timer functions provide the option
to generate a wake-up signal on an interrupt pin. An
offset register allows fine tuning of the clock.
Applications
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Wireless sensors and RFID tags
and other
powered, low duty cycle applications.
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Power bridging
to provide uninterruptible RTC
function during exchange of main batteries.
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Consumer appliances
that have real-time
clocks; provides switchover power from main
supply to backup battery.
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Business and industrial systems
such as:
network routers, point-of-sale terminals, single-
board computers, test equipment, multi-function
printers, industrial controllers, and utility meters.
• Time keeping application
• Battery powered devices
• Metering
• High duration timers
• Daily alarms
• Low standby power applications
Figure 1: CBC34123 Pin-out Diagram
©2012 Cymbet Corporation • Tel: +1-763-633-1780 • www.cymbet.com
DS-72-31 V.08
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