CBC34523 EnerChip™ RTC

Preliminary
CBC34523 EnerChip™ RTC
I2C Real-Time Clock/Calendar with Integrated Backup Power
Features
• Integrated rechargeable solid state battery with
power-fail detect and automatic switchover, providing greater than 24 hours of backup
• Smallest commercially available RTC with integrated backup power in compact 5mm x 6mm
1.4mm QFN package
• Temperature compensated charge control
• Integrated EnerChip™ recharged at VDD > 2.5V
• SMT - lead-free reflow tolerant
• Real time clock provides year, month, day, weekday, hours, minutes, and seconds based on a
32.768 kHz quartz crystal
• Resolution: seconds to years
• Watchdog functionality
• Freely programmable timer and alarm with interrupt capability
• 2-line I2C-bus with separate, but combinable
data input and output
• Selectable integrated oscillator load capacitors
for CL = 7 pF or CL = 12.5 pF
• Internal power-on reset (POR)
• Open-drain interrupt or clock output pins
• Programmable offset register for frequency
adjustment
• Eco-friendly, RoHS compliant - tested
Applications
• Wireless sensors and RFID tags and other
powered, low duty cycle applications.
• Power bridging to provide uninterrupted 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, singleboard 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
5mm x 6mm x 1.4mm 16-QFN Package
General Description
The EnerChip RTC CBC34523-Q5C combines a RealTime Clock (RTC) and calendar optimized for low
power applications with an integrated rechargeable
solid state backup power source 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 provides thousands
of charge-discharge cycles from the integrated
the EnerChip and manages battery charging,
discharge cutoff, power switchover, and temperature
compensation to maximize the service life of the
device. The CBC34523 provides greater than 24
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 RoHScompliant. The EnerChip is charged automatically
anytime VDD is above 2.5V.
Data is transferred serially via an I2C-bus with a
maximum data rate of 1000 Kbits/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.
Figure 1: CBC34523 Pin-out Diagram
©2012 Cymbet Corporation • Tel: +1-763-633-1780 • www.cymbet.com
DS-72-32 Rev V.05
Page 1 of 9
Preliminary
CBC34523 EnerChip™ RTC
16
OSCI
1
OSCO
CLKOUT
OSCILLATOR
32.768 kHz
C
OSC0
DIVIDER
&
OFFSET FUNCTION
C
OSC1
0Eh
Offset_register
0Fh
Timer_CLKOUT_ctrl
8
CLOCKOUT
INT1/CLKOUT
TIMER FUNCTION
6
VCHG
7
VEC
14 RESET
15
ENERCHIP
AND
CHARGER
EN
10h
Tmr_A_freq_ctrl
11h
Tmr_A_reg
12h
Tmr_B_freq_ctrl
13h
Tmr_B_reg
INTERRUPT
CONTROL
5
VBAT
13
VDD
3
VSS
2
NC
11
NC
9
SDA
10
SCL
BATTERY
BACKUP
SWITCH-OVER
CIRCUITRY
POWERON
RESET
I2CBUS
INTERFACE
00h
Control_1
01h
Control_2
02h
Control_3
03h
Seconds
04h
Minutes
05h
Hours
TIME
06h
Days
07h
Weekdays
08h
Months
09h
Years
ALARM FUNCTION
0Ah
Minute_alarm
0Bh
Hour_alarm
0Ch
Day_alarm
0Dh
Weekday_alarm
INT2
4
Figure 2: CBC34523 EnerChip RTC Block Diagram with Registers
Figure 3: Internal Schematic of CBC34523 EnerChip RTC
©2012 Cymbet Corporation • Tel: +1-763-633-1780 • www.cymbet.com
DS-72-32 Rev V.05
Page 2 of 9
12
Preliminary
CBC34523 EnerChip™ RTC
CBC34523 Input/Output Descriptions
Pin Number
Label
Description
1
OSCO
Oscillator output; high-impedance node; minimize wire length between
quartz and package
2
NC
Not connected; do not connect and do not use it as feed through
3
VSS
Ground
4
INT2/
Interrupt 2 output (open-drain; active LOW)
5
VBAT
Backup battery supply input
6
VCHG
4.1V (typical) charging source - connect to VBAT only, or VBAT and optional
EnerChip(s)
7
VEC
Positive terminal of integrated thin film battery - connect to VCHG and nothing else
8
CLKOUT
Clock output (open-drain)
9
SDA
Serial data input/output
10
SCL
Serial clock input
11
NC
Not connected; do not connect and do not use it as feed through
12
INT1/
CLKOUT/
Interrupt 1 / clock output (open-drain)
13
VDD
Supply voltage
14
RESET/
Output signal indicating RTC is operating in backup power mode
15
EN
Charge pump enable; activates VCHG 4.1V (typ.) charging source
OSCI
Oscillator input; high-impedance node; minimize wire length between quartz
and package
16
Package Dimensions
5mm x 6mm x 1.4mm
Pad Pitch
0.8mm
Pad Dimensions
0.4mm x 0.3mm
Figure 4: CBC34523 EnerChip RTC Package Pin-Out (top view, looking through package)
EnerChip Properties
Energy capacity (typical): Recharge time to 80%:
Charge/discharge cycles: Operating temperature:
Storage temperature:
Minimum VDD to charge EnerChip:
5µAh
10 minutes
>5000 to 10% depth-of-discharge
-20°C to +70°C
-40°C to +125°C
2.5V
©2012 Cymbet Corporation • Tel: +1-763-633-1780 • www.cymbet.com
DS-72-32 Rev V.05
Page 3 of 9
Preliminary
CBC34523 EnerChip™ RTC
Absolute Maximum Ratings
PARAMETER
CONDITION
MIN
TYPICAL
MAX
UNITS
VDD with respect to GND
25°C
GND - 0.3
-
6.0
V
ENABLE Input Voltage
25°C
GND - 0.3
-
VDD+0.3
V
VBAT
25°C
3.0
-
4.15
V
25°C
3.0
-
4.15
V
RESET Output Voltage
25°C
GND - 0.3
-
VOUT+0.3
V
CP, Flying Capacitor Voltage
25°C
GND - 0.3
-
6.0
V
CN
25°C
GND - 0.3
-
VDD+0.3
V
(1)
VCHG
(1)
(1)
No external connections to these pins are allowed, except parallel EnerChips.
Integrated EnerChip Thin Film Battery Operating Characteristics
PARAMETER
CONDITION
MIN
TYPICAL
MAX
UNITS
Non-recoverable
-
2.5
-
% per year
Recoverable
-
1.5
-
% per year
Operating Temperature
-
-20
25
Storage Temperature
-
-40
-
10% depth-of-discharge
5000
-
-
cycles
50% depth-of discharge
1000
-
-
cycles
10% depth-of-discharge
2500
-
-
cycles
50% depth-of-discharge
500
-
-
cycles
Charge cycle 2
-
11
22
Charge cycle 1000
-
45
70
150nA discharge; 25°C
5
-
-
Self-Discharge (5 yr. average)
Recharge Cycles
(to 80% of rated
capacity)
25°C
40°C
Recharge Time (to 80% of rated
capacity; 4.1V charge; 25°C)
Capacity
(1)
First month recoverable self-discharge is 5% average.
(2)
Storage temperature is for uncharged EnerChip CC device.
(1)
+70
+125
°C
(2)
°C
minutes
µAh
Note: All specifications contained within this document are subject to change without notice.
©2012 Cymbet Corporation • Tel: +1-763-633-1780 • www.cymbet.com
DS-72-32 Rev V.05
Page 4 of 9
Preliminary
CBC34523 EnerChip™ RTC
Functional Description of Integrated PCF8523 Real-Time Clock
The PCF8523 contains:
•20 8-bit registers with an auto-incrementing address register
•An on-chip 32.768 kHz oscillator with two integrated load capacitors
•A frequency divider, which provides the source clock for the Real-Time Clock (RTC)
•A programmable clock output
•A 1 Mbit/s I2C-bus interface
•An offset register, which allows fine-tuning of the clock
All 20 registers are designed as addressable 8-bit registers although not all bits are implemented.
•The first three registers (memory address 00h, 01h, and 02h) are used as control and status registers
•The addresses 03h through 09h are used as counters for the clock function (seconds up to years)
•Addresses 0Ah through 0Dh define the alarm condition
•Address 0Eh defines the offset calibration
•Address 0Fh defines the clock-out mode and the addresses 10h and 12h the timer mode
•Addresses 11h and 13h are used for the timers
Standby Mode
When the device is first powered up from the battery (VBAT) but without a main supply (VDD), the PCF8523
automatically enters the standby mode. In standby mode, the PCF8523 does not draw any power from the
backup battery until the device is powered up from the main power supply VDD. Thereafter, the device switches
over to battery backup mode whenever the main power supply VDD is lost.
It is also possible to enter into standby mode when the chip is already supplied by the main power supply VDD and
a backup battery is connected. To enter the standby mode, the power management control bits PM[2:0] have to
be set logic 111. Then the main power supply VDD must be removed. As a result of it, the PCF8523 enters the
standby mode and does not draw any current from the backup battery before it is powered up again from main
supply VDD.
The interface is disabled in battery backup operation:
•Interface inputs are not recognized, preventing extraneous data being written to the device
•Interface outputs are high-impedance
©2012 Cymbet Corporation • Tel: +1-763-633-1780 • www.cymbet.com
DS-72-32 Rev V.05
Page 5 of 9
Preliminary
CBC34523 EnerChip™ RTC
PCF8523 Register Overview
The 20 registers of the PCF8523 are auto-incrementing after each read or write data byte up to register 13h.
After register 13h, the auto-incrementing will wrap around to address 00h.
Bit positions labeled as ‘-’ are not implemented and will return a ‘0’ when read. Bit ‘T’ must always be written with
logic ‘0’.
Address Register name
Bit
7
6
5
4
3
2
1
0
CIE
Control registers
00h
Control_1
CAP_SEL T
STOP
SR
12_24
SIE
AIE
01h
Control_2
WTAF
CTBF
SF
AF
WTAIE
CTAIE CTBIE
02h
Control_3
PM[2:0]
-
BSF
BLF
BSIE
CTAF
BLIE
Time and date registers
03h
Seconds
OS
SECONDS (0 to 59)
04h
Minutes
-
MINUTES (0 to 59)
05h
Hours
-
-
AMPM
HOURS (1 to 12 in 12 hour mode)
HOURS (0 to 23 in 24 hour mode)
06h
Days
-
-
DAYS (1 to 31)
07h
Weekdays
-
-
-
-
08h
Months
-
-
-
MONTHS (1 to 12)
09h
Years
YEARS (0 to 99)
-
WEEKDAYS (0 to 6)
Alarm registers
0Ah
Minute_alarm
AE_M
MINUTE_ALARM (0 to 59)
0Bh
Hour_alarm
AE_H
-
AMPM
-
HOUR_ALARM (0 to 23 in 24 hour mode)
HOUR_ALARM (1 to 12 in 12 hour mode)
0Ch
Day_alarm
AE_D
-
DAY_ALARM (1 to 31)
0Dh
Weekday_alarm AE_W
-
-
-
-
WEEKDAY_ALARM (0 to 6)
Offset register
0Eh
Offset
MODE
OFFSET[6:0]
CLOCKOUT and timer registers
0Fh
Tmr_CLKOUT_
ctrl
TAM
TBM
COF[2:0]
10h
Tmr_A_freq_ctrl
-
-
-
11h
Tmr_A_reg
TIMER_A_VALUE[7:0]
12h
Tmr_B_freq_ctrl
-
13h
Tmr_B_reg
TIMER_B_VALUE[7:0]
TBW[2:0]
TAC[1:0]
-
-
TAQ[2:0]
-
TBQ[2:0]
©2012 Cymbet Corporation • Tel: +1-763-633-1780 • www.cymbet.com
DS-72-32 Rev V.05
TBC
Page 6 of 9
Preliminary
CBC34523 EnerChip™ RTC
POWER SUPPLY CURRENT CHARACTERISTICS
Ta = -20ºC to +70ºC
CHARACTERISTIC
SYMBOL
CONDITION
ENABLE=GND
Quiescent Current
IQ
ENABLE=VDD
EnerChip Cutoff Current
(IQBATON adds to RTC
current when in backup
mode)
MIN
MAX
UNITS
VDD=3.3V
-
3.5
µA
VDD=5.5V
-
6.0
µA
VDD=3.3V
-
35
µA
VDD=5.5V
-
38
µA
IQBATOFF
VBAT < VBATCO,
VOUT=0
-
0.5
nA
IQBATON
VBAT > VBATCO,
ENABLE=VDD, IOUT=0
-
42
nA
INTERFACE LOGIC SIGNAL CHARACTERISTICS
VDD = 2.5V to 5.5V, Ta = -20ºC to +70ºC
CHARACTERISTIC
SYMBOL
CONDITION
MIN
High Level Input Voltage
VIH
-
Low Level Input Voltage
VIL
-
High Level Output Voltage
VOH
VDD>VTH (see Figures 4
and 5) IL=10µA
Low Level Output Voltage
VOL
Logic Input Leakage Current
IIN
(1)
MAX
UNITS
VDD - 0.5
-
Volts
-
0.5
Volts
VDD 0.04V (1)
-
Volts
IL = -100µA
-
0.3
Volts
0<VIN<VDD
-1.0
+1.0
nA
RESET tracks VDD; RESET = VDD - (IOUT x ROUT).
RESET SIGNAL AC/DC CHARACTERISTICS
VDD = 2.5V to 5.5V, Ta = -20ºC to +70ºC
CHARACTERISTIC
SYMBOL
CONDITION
MIN
MAX
UNITS
VDD Rising to RESET
Rising
tRESETH
VDD rising from 2.8V TO 3.1V
in <10µs
60
200
ms
VDD Falling to RESET
Falling
tRESETL
VDD falling from 3.1V to 2.8V
in <100ns
0.5
2
µs
TRIP Voltage
VDD Rising
VRESET
VMODE=GND
2.85
3.15
V
VMODE=VDD
60
100
VMODE=GND
45
75
VMODE = VDD/2
30
50
RESET Hysteresis
Voltage (3)
(VDD to RESET)
VHYST
mV
(2)
User-selectable trip voltage can be set by placing a resistor divider from the VMODE pin to GND. Refer to Figure 8.
(3)
The hysteresis is a function of trip level in Mode 2. Refer to Figure 9.
©2012 Cymbet Corporation • Tel: +1-763-633-1780 • www.cymbet.com
DS-72-32 Rev V.05
Page 7 of 9
Preliminary
CBC34523 EnerChip™ RTC
CHARGE PUMP CHARACTERISTICS
VDD = 2.5V to 5.5V, Ta = -20ºC to +70ºC
CHARACTERISTIC
SYMBOL
ENABLE=VDD to Charge
Pump Active
tCPON
ENABLE Falling to
Charge Pump Inactive
tCPOFF
CONDITION
ENABLE to 3rd charge pump
pulse, VDD=3.3V
-
MIN
MAX
UNITS
60
80
µs
0
1
µs
-
120
KHz (1)
150
300
Ω
Charge Pump Frequency
fCP
Charge Pump
Resistance
RCP
Delta VBAT, for IBAT charging
current of 1µA to 100µA
CFLY=0.1µF, CBAT=1.0µF
VCHG Output Voltage
VCP
CFLY=0.1µF, CBAT=1.0µF,
IOUT=1µA, Temp=+25ºC
4.075
4.125
V
VCHG Temp. Coefficient
TCCP
IOUT=1µA, Temp=+25ºC
-2.0
-2.4
mV/ºC
Charge Pump Current
Drive
ICP
IBAT=1mA
CFLY=0.1µF, CBAT=1.0µF
1.0
-
mA
ENABLE=VDD
2.5
-
V
Charge Pump on Voltage
(1)
VENABLE
fCP = 1/tCPPER
ADDITIONAL CHARACTERISTICS
Ta = -20ºC to +70ºC
CHARACTERISTIC
VBAT Cutoff Threshold
SYMBOL
VBATCO
Cutoff Temp. Coefficient
TCCO
VBAT Cutoff Delay Time
tCOOFF
CONDITION
LIMITS
IOUT=1µA
VBAT from 40mV above to
20mV below VBATCO
IOUT=1µA
UNITS
MIN
MAX
2.75
3.25
V
+1
+2
mV/ºC
40
-
ms
Note: All specifications contained within this document are subject to change without notice
Important Reference Documents
For complete specifications of the integrated PCF8523 Real-Time Clock, see here:
http://www.nxp.com/documents/data_sheet/PCF8523.pdf
For complete specifications of the Cymbet 5µAh EnerChip and integrated power management circuit, see here:
http://www.cymbet.com/pdfs/DS-72-21.pdf
©2012 Cymbet Corporation • Tel: +1-763-633-1780 • www.cymbet.com
DS-72-32 Rev V.05
Page 8 of 9
Preliminary
CBC34523 EnerChip™ RTC
Ordering Information
EnerChip CC Part Number
Description
Notes
CBC34523-Q5C
EnerChip RTC in 5mm x 6mm x
1.4mm 16-QFN Land Grid Array
Shipped in Tube
CBC34523-Q5C-TR1
CBC34523-Q5C-TR5
EnerChip RTC in 5mm x 6mm x
1.4mm 16-QFN Land Grid Array
Tape-and-Reel - 1000 pcs (TR1) or
5000 pcs (TR5) per reel
U.S. Patent No. 8,144,508. Additional U.S. and Foreign Patents Pending
Disclaimer of Warranties; As Is
The information provided in this data sheet is provided “As Is” and Cymbet Corporation disclaims all representations or warranties of any
kind, express or implied, relating to this data sheet and the Cymbet EnerChip product described herein, including without limitation, the
implied warranties of merchantability, fitness for a particular purpose, non-infringement, title, or any warranties arising out of course of
dealing, course of performance, or usage of trade. Cymbet EnerChip products are not authorized for use in life critical applications. Users
shall confirm suitability of the Cymbet EnerChip product in any products or applications in which the Cymbet EnerChip product is adopted
for use and are solely responsible for all legal, regulatory, and safety-related requirements concerning their products and applications and
any use of the Cymbet EnerChip product described herein in any such product or applications.
Cymbet, the Cymbet Logo, and EnerChip are Cymbet Corporation Trademarks
©2012 Cymbet Corporation • Tel: +1-763-633-1780 • www.cymbet.com
DS-72-32 Rev V.05
Page 9 of 9