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
Applications
•
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. Longer backup
time can be achieved by adding an external EnerChip
to the VCHG pin. 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.
Wireless sensors and RFID tags
and other
powered, low duty cycle applications.
• Power bridging
to provide uninterruptible RTC
function during exchange of main batteries.
• Consumer appliances
that have real-time
clocks; provides switchover power from main
supply to backup battery.
• 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
DS-72-31 V.13
©2013-2015 Cymbet Corporation • Tel: +1-763-633-1780 • www.cymbet.com
Page 1 of 14
Preliminary
CBC34123 EnerChip™ RTC
CBC34123 Input/Output Descriptions
Pin Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Label
OSCO
TEST
INT/
CE
VSS
VCHG
VEC
SDO
SDI
SCL
CLKOE
CLKOUT
VDD
RESET/
EN
OSCI
Description
Oscillator output; high-impedance node; minimize wire length between
quartz and package
Test pin; not user accessible; connect to VSS or leave floating (internally
pulled down)
Interrupt output (open-drain; active LOW)
Chip enable input (active HIGH) with internal pull down
Ground
4.1V (typical) charging source - connect to VEC and/or optional EnerChip(s)
for extended backup time
Positive terminal of integrated thin film battery - connect only to VCHG via
PCB trace
Serial data output, push-pull; high-impedance when not driving; can be con-
nected to SDI for single wire data line
Serial data input; may float when CE is inactive
Serial clock input; may float when CE is inactive
CLKOUT enable or disable pin; enable is active HIGH; connect to VSS for low
power operation
Clock output (open-drain)
Supply voltage; positive or negative steps in VDD can affect oscillator perfor-
mance; recommend 100nF decoupling close to the device
Output signal indicating RTC is operating in backup power mode
Charge pump enable; activates VCHG 4.1V (typ.) charging source
Oscillator input; high-impedance node; minimize wire length between quartz
and package
Package
Dimensions
(mm)
Figure 4: CBC34123 Package (left: top view, looking through package; right: pad dimensions)
EnerChip Properties
Energy capacity (typical):
Recharge time to 80%:
Charge/discharge cycles:
Operating temperature:
Storage temperature:
Minimum VDD to charge EnerChip:
DS-72-31 V.13
5µAh
10 minutes
>5000 to 10% depth-of-discharge
-30°C to +70°C
-40°C to +125°C
2.5V
Page 3 of 14
©2013-2015 Cymbet Corporation • Tel: +1-763-633-1780 • www.cymbet.com
Preliminary
CBC34123 EnerChip™ RTC
Absolute Maximum Ratings
PARAMETER / PIN
V
DD
with respect to GND
ENABLE Input Voltage
V
EC
(1)
V
CHG
(1)
CONDITION
25°C
25°C
25°C
25°C
25°C
MIN
GND - 0.3
GND - 0.3
3.0
3.0
GND - 0.3
TYPICAL
-
-
-
-
-
MAX
6.0
V
DD
+0.3
4.15
4.15
2.7
UNITS
V
V
V
V
V
RESET Output Voltage
INT/, CE, TEST, OSCI, OSCO, SDO,
SDI, SCL, CLKOE, CLKOUT
(1)
See NXP PCF2123 Data Sheet
No external connections to these pins are allowed, except parallel EnerChips for extended backup time.
Integrated EnerChip Thin Film Battery Operating Characteristics
PARAMETER
Self-Discharge (5 yr. average)
Operating Temperature
Storage Temperature
Recharge Cycles
(to 80% of rated
capacity)
25°C
40°C
CONDITION
Non-recoverable
Recoverable
MIN
-
-
-30
-40
5000
1000
2500
500
-
-
5
TYPICAL
2.5
1.5
(1)
25
-
-
-
-
-
11
45
-
MAX
-
-
+70
+125
(2)
-
-
-
-
22
70
-
UNITS
% per year
% per year
°C
°C
cycles
cycles
cycles
cycles
minutes
µAh
-
-
10% depth-of-discharge
50% depth-of discharge
10% depth-of-discharge
50% depth-of-discharge
Charge cycle 2
Charge cycle 1000
40nA discharge; 25°C
Recharge Time (to 80% of rated
capacity; 4.1V charge; 25°C)
(3)
Capacity (see Figure 5)
(1)
(2)
(3)
First month recoverable self-discharge is 5% average.
Storage temperature is for uncharged EnerChip CC device.
EnerChip charging time increases approximately 2x per 10°C decrease in temperature.
Figure 5: Typical Discharge Characteristics of the CBC005 EnerChip Within the CBC34123
Note: All specifications contained within this document are subject to change without notice.
DS-72-31 V.13
©2013-2015 Cymbet Corporation • Tel: +1-763-633-1780 • www.cymbet.com
Page 4 of 14
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