Cymbet CBC34813-M5C-TR5 Spi real-time clock/calendar with integrated backup power Datasheet

Preliminary
CBC34813 EnerChip™ RTC
SPI Real-Time Clock/Calendar with Integrated Backup Power
Features
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Ultra low power Real Time Clock with Integrated
rechargeable EnerChip™ solid state battery,
power-fail detect and automatic switchover,
providing greater than 6 days of RTC backup
5mm x 5mm x 1.4mm QFN package is the
smallest commercially available RTC having
integrated backup power
Temperature-compensated charge control
Integrated EnerChip™ recharged at VDD > 2.5V
SMT assembly - lead-free reflow solder tolerant
Counters for hundredths, seconds, minutes,
hours, date, month, year, century, and weekday
based on a 32.768 kHz oscillator
Automatic leap year calculation
Alarm capability on all counters
2 general purpose outputs
64 bytes of RAM
Advanced crystal calibration to ± 2 ppm
Advanced RC calibration to ± 16 ppm
Automatic calibration of RC oscillator to crystal
oscillator
SPI-bus (up to 400kHz)
Eco-friendly, RoHS compliant - tested
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.
Ultra Low Power Timers using only 35nA can be
implemented with the CBC34813
Wireless sensors and RFID tags and other
powered, low duty cycle applications.
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 5mm x 1.4mm 16-pin QFN Package
General Description
The EnerChip RTC CBC34813-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
CBC34813 provides greater than 6 days of backup
time in the event main power is interrupted. The
integrated EnerChip recharges quickly, has extremely
low self-discharge, is non-flammable, and RoHScompliant. The EnerChip is charged automatically
anytime VDD is above 2.5V.
Data is transferred serially via an SPI-bus. Alarm
and timer functions provide the option to generate a
wake-up signal on an interrupt pin.
Figure 1: CBC34813 Pin-out Diagram
©2013 Cymbet Corporation • Tel: +1-763-633-1780 • www.cymbet.com
DS-72-38 V.01
Page 1 of 9
Preliminary
CBC34813 EnerChip™ RTC
Figure 2: Functional Block Diagram of CBC34813 (AM0813) Real-Time Clock
Figure 3: Internal Schematic of CBC34813 EnerChip RTC
©2013 Cymbet Corporation • Tel: +1-763-633-1780 • www.cymbet.com
DS-72-38 V.01
Page 2 of 9
Preliminary
CBC34813 EnerChip™ RTC
CBC34813 Input/Output Descriptions
Pin Number
Label
Description
1
XO
Crystal output
2
VCAP
External capacitor connection to supply switchover current at cold temp.
(optional)
3
nIRQ2
Interrupt 2 / Output
4
nCE
RTC SPI chip select
5
VSS
Ground
6
VCHG
4.1V (typical) charging source - connect to VBAT and/or optional
EnerChip(s)
7
VEC
Positive terminal of integrated thin film battery - connect to only to VCHG
via PCB trace
8
SDO
SPI-bus data output
9
SDI
SPI-bus data input
10
SCL
SPI-bus interface clock
11
AF
Autocalibration filter
12
FOUT/nIRQ
Interrupt 1 / Function output
13
VDD
Supply voltage; positive or negative steps in VDD can affect oscillator performance; recommend 100nF decoupling close to the device (see Fig. 30)
14
RESET/
Output signal indicating RTC is operating in backup power mode
15
EN
Charge pump enable; activates VCHG 4.1V (typ.) charging source
16
XI
Crystal input
Package
Dimensions
(mm)
Figure 4: CBC34813 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:
5µAh
<15 minutes
>5000 to 10% depth-of-discharge
-10°C to +70°C
-40°C to +125°C
2.5V
©2013 Cymbet Corporation • Tel: +1-763-633-1780 • www.cymbet.com
DS-72-38 V.01
Page 3 of 9
Preliminary
CBC34813 EnerChip™ RTC
Absolute Maximum Ratings
PARAMETER / PIN
CONDITION
MIN
TYPICAL
MAX
UNITS
VDD with respect to GND
25°C
GND - 0.3
-
3.6
V
ENABLE Input Voltage
25°C
GND - 0.3
-
VDD+0.3
V
VEC
25°C
3.0
-
4.15
V
25°C
3.0
-
4.15
V
RESET Output Voltage
25°C
GND - 0.3
-
2.7
V
VCAP
25°C
GND - 0.3
-
3.6
V
(1)
VCHG
(1)
XI, XO, SDI, SDO, SCL, nCE, AF, FOUT/
nIRQ, nIRQ2
(1)
See Ambiq Micro AM0813 Data Sheet
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
-
-10
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
40nA 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.
©2013 Cymbet Corporation • Tel: +1-763-633-1780 • www.cymbet.com
DS-72-38 V.01
Page 4 of 9
Preliminary
CBC34813 EnerChip™ RTC
Important Reference Documents
For complete specifications of the integrated AM0813 Real-Time Clock, see here:
http://ambiqmicro.com
For complete specifications of the Cymbet 5µAh EnerChip and integrated power management circuit, reference
the CBC3105 datasheet here: http://www.cymbet.com/pdfs/DS-72-21.pdf .
The EnerChip and power management functions within the CBC34813 are configured as in Mode 1 (VMODE =
GND) as described in the CBC3105 DS-72-21 data sheet.
For guidelines regarding crystal selection and other important information pertaining to the AM0813, see here:
http://ambiqmicro.com/resource-center/
Functional Description of Integrated AM0813 Real-Time Clock
The AM0813 serves as a full function RTC for host processors such as microcontrollers. The AM0813 includes 3
distinct feature groups: 1) baseline timekeeping features with 32.768 kHz oscillator and 2) advanced
timekeeping features, and 3) basic power management features. Functions from each feature group may be
controlled via memory mapped registers. These registers are accessed using either an I2C serial interface (e.g.,
in the AM0803) or a SPI serial interface (e.g., in the AM0813). For more information on the AM0813, see here:
http://ambiqmicro.com/0800-series.
Low Power Operation
Minimum power operation will be achieved by turning off the charge pump in the power management circuit by
driving ENABLE low once the internal EnerChip has been charged - typically one hour to full charge at room
temperature.
The RTC has 3 low power modes, allowing the designer to make appropriate trade-offs between power
consumption and timing accuracy. Operating current drawn by the RTC is as follows:
<15 nA with RC oscillator
<20 nA with RC oscillator and autocalibration
<55 nA with crystal oscillator
In addition to the RTC current, the integrated power management circuit typically draws 20-25nA from the
EnerChip storage device at room temperature.
©2013 Cymbet Corporation • Tel: +1-763-633-1780 • www.cymbet.com
DS-72-38 V.01
Page 5 of 9
Preliminary
CBC34813 EnerChip™ RTC
Crystal Oscillator Selection
The AM0813 should work with any standard 32.768kHz tuning fork crystal with a load capacitance rating from
0 - 12pF and an ESR from 0 - 90kohms. Recommendations are as follows:
•
•
•
•
Crystal load capacitance rating: 0 - 12pF
Crystal ESR rating: 0 – 90kohms max
No additional loading capacitors on the board
Stray PCB capacitance on XO/XI: 2pF or less (less is better)
Typically, an oscillator allowance (OA) of 260-290kohms is generated. Increasing the loading capacitance on
the XI/XO pins will decrease the OA and using crystals with a higher ESR will reduce the OA margin. The crystal
will not affect the AM0813 RTC current because a fixed bias current to the crystal is used. No external load
capacitance is required because the frequency offset from the crystal is digitally calibrated out, to within +/2ppm. Mainstream crystals (3.2mm x 1.5mm) generally have a maximum ESR rating of 70kohms. The smaller
2.0mm x 1.2mm crystals generally have a maximum ESR of 90kohms. Some crystal vendors, such as Epson
or Micro Crystal, might have some of the smaller crystals with lower ESR. Below is a list of crystals from several
vendors that have been tested:
Abracon: ABS07-32.768KHZ-7-T, ABS06-32.768KHZ-9-T, ABS25.32.768KHZ-T
Epson: C-002RX, FC-135, FC-12D, FC-12M
Micro Crystal: CC7V-T1A, CM7V-T1A
CBC34813 (AM0813) Register Definitions (00 to 0F)
The following register bits must be set prior to any switchover, even from VDD to the EnerChip.
BREF bits: The default value out of reset is 0000. This needs to be reprogrammed to 1111.
IOBM bit: The default value out of reset is 1. This needs to be reprogrammed to 0.
©2013 Cymbet Corporation • Tel: +1-763-633-1780 • www.cymbet.com
DS-72-38 V.01
Page 6 of 9
Preliminary
CBC34813 EnerChip™ RTC
POWER SUPPLY CURRENT CHARACTERISTICS OF INTEGRATED CBC910 POWER
MANAGEMENT CIRCUIT ONLY
Ta = -20ºC to +70ºC
CHARACTERISTIC
Quiescent Current
(CBC910 power
management circuit
only; VDD > VRESET ; RTC
current not included)
EnerChip Cutoff Current
(IQBATON adds to RTC
current when in backup
mode)
SYMBOL
CONDITION
ENABLE=GND
IQ
ENABLE=VDD
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
MAX
UNITS
VIH
-
VDD - 0.5
-
Volts
High Level Input Voltage
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)
-
-
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
VHYST
VMODE=GND
45
75
mV
RESET Hysteresis
Voltage
(VDD to RESET)
©2013 Cymbet Corporation • Tel: +1-763-633-1780 • www.cymbet.com
DS-72-38 V.01
Page 7 of 9
Preliminary
CBC34813 EnerChip™ RTC
CHARGE PUMP CHARACTERISTICS (PERTAINS TO INTEGRATED CBC910 POWER MANAGEMENT CIRCUIT)
(NOTE: THIS TABLE PROVIDES IMPORTANT INFORMATION WHEN CONNECTING ADDITIONAL ENERCHIPS TO VCHG.)
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
MIN
MAX
UNITS
60
80
µs
0
1
µs
-
120
KHz (1)
150
300
Ω
ENABLE to 3rd charge pump
pulse, VDD=3.3V
-
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
UNITS
MIN
MAX
2.75
3.25
V
+1
+2
mV/ºC
40
-
ms
IOUT=1µA
VBAT from 40mV above to
20mV below VBATCO
IOUT=1µA
Note: All specifications contained within this document are subject to change without notice
©2013 Cymbet Corporation • Tel: +1-763-633-1780 • www.cymbet.com
DS-72-38 V.01
Page 8 of 9
Preliminary
CBC34813 EnerChip™ RTC
Ordering Information
EnerChip RTC Part Number
Description
Notes
CBC34813-M5C
EnerChip RTC in 5mm x 5mm x
1.4mm 16-QFN Land Grid Array
Shipped in Tube
CBC34813-M5C-TR1
CBC34813-M5C-TR5
EnerChip RTC in 5mm x 5mm x
1.4mm 16-QFN Land Grid Array
Tape-and-Reel - 1000 pcs (TR1) or
5000 pcs (TR5) per reel
CBC-EVAL-12-34813
EnerChip RTC Evaluation Kit
USB based Eval Kit with
CBC34813 tab board
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
©2013 Cymbet Corporation • Tel: +1-763-633-1780 • www.cymbet.com
DS-72-38 V.01
Page 9 of 9
Similar pages