?2013 cymbet corporation ? tel: +1-763-633-1780 ? www.cymbet.com ds-72-38 v.01 page 1 of 9 spi real-time clock/calendar with integrated backup power cbc34813 enerchip? rtc 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 refow 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 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-fammable, and rohs- compliant. 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. 5mm x 5mm x 1.4mm 16-pin qfn package 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, 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 preliminary figure 1: cbc34813 pin-out diagram
?2013 cymbet corporation ? tel: +1-763-633-1780 ? www.cymbet.com ds-72-38 v.01 page 2 of 9 figure 3: internal schematic of cbc34813 enerchip rtc figure 2: functional block diagram of cbc34813 (am0813) real-time clock cbc34813 enerchip? rtc preliminary
?2013 cymbet corporation ? tel: +1-763-633-1780 ? www.cymbet.com ds-72-38 v.01 page 3 of 9 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 flm 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 flter 12 fout/nirq interrupt 1 / function output 13 vdd supply voltage; positive or negative steps in vdd can affect oscillator per - formance; 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 cbc34813 input/output descriptions enerchip properties energy capacity (typical): 5ah recharge time to 80%: <15 minutes charge/discharge cycles: >5000 to 10% depth-of-discharge operating temperature: -10c to +70c storage temperature: -40c to +125c minimum vdd to charge enerchip: 2.5v figure 4: cbc34813 package (left: top view, looking through package; right: pad dimensions) package dimensions (mm) cbc34813 enerchip? rtc preliminary
?2013 cymbet corporation ? tel: +1-763-633-1780 ? www.cymbet.com ds-72-38 v.01 page 4 of 9 absolute maximum ratings parameter condition min typical max units self-discharge (5 yr. average) non-recoverable - 2.5 - % per year recoverable - 1.5 (1) - % per year operating temperature - -10 25 +70 c storage temperature - -40 - +125 (2) c recharge cycles (to 80% of rated capacity) 25c 10% depth-of-discharge 5000 - - cycles 50% depth-of discharge 1000 - - cycles 40c 10% depth-of-discharge 2500 - - cycles 50% depth-of-discharge 500 - - cycles recharge time (to 80% of rated capacity; 4.1v charge; 25c) charge cycle 2 - 11 22 minutes charge cycle 1000 - 45 70 capacity 40na discharge; 25c 5 - - ah (1) first month recoverable self-discharge is 5% average. (2) storage temperature is for uncharged enerchip cc device. note: all specifcations contained within this document are subject to change without notice. parameter / pin condition min typical max units v dd with respect to gnd 25c gnd - 0.3 - 3.6 v enable input voltage 25c gnd - 0.3 - v dd +0.3 v v ec (1) 25c 3.0 - 4.15 v v chg (1) 25c 3.0 - 4.15 v reset output voltage 25c gnd - 0.3 - 2.7 v vcap 25c gnd - 0.3 - 3.6 v xi, xo, sdi, sdo, scl, nce, af, fout/ nirq, nirq2 see ambiq micro am0813 data sheet integrated enerchip thin film battery operating characteristics (1) no external connections to these pins are allowed, except parallel enerchips. cbc34813 enerchip? rtc preliminary
?2013 cymbet corporation ? tel: +1-763-633-1780 ? www.cymbet.com ds-72-38 v.01 page 5 of 9 important reference documents for complete specifcations of the integrated am0813 real-time clock, see here: http://ambiqmicro.com for complete specifcations of the cymbet 5 ah 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 confgured 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. cbc34813 enerchip? rtc preliminary
?2013 cymbet corporation ? tel: +1-763-633-1780 ? www.cymbet.com ds-72-38 v.01 page 6 of 9 cbc34813 (am0813) register defnitions (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. 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 C 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 fxed 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 enerchip? rtc preliminary
?2013 cymbet corporation ? tel: +1-763-633-1780 ? www.cymbet.com ds-72-38 v.01 page 7 of 9 power supply current characteristics of integrated cbc910 power management circuit only t a = -20 oc to +70oc characteristic symbol condition min max units quiescent current (cbc910 power management circuit only; v dd > v reset ; rtc current not included) i q enable=gnd v dd =3.3v - 3.5 a v dd =5.5v - 6.0 a enable=v dd v dd =3.3v - 35 a v dd =5.5v - 38 a enerchip cutoff current (i qbaton adds to rtc current when in backup mode) i qbatoff v bat < v batco , v out =0 - 0.5 na i qbaton v bat > v batco , enable=v dd , i out =0 - 42 na interface logic signal characteristics v dd = 2.5v to 5.5v, t a = -20 oc to +70oc characteristic symbol condition min max units high level input voltage v ih - v dd - 0.5 - volts low level input voltage v il - - 0.5 volts high level output voltage v oh v dd >v th (see figures 4 and 5) i l =10a v dd - 0.04v (1) - volts low level output voltage v ol i l = -100a - 0.3 volts logic input leakage current i in 0 ?2013 cymbet corporation ? tel: +1-763-633-1780 ? www.cymbet.com ds-72-38 v.01 page 8 of 9 charge pump characteristics (pertains to integrated cbc910 power management circuit) (note: this table provides important information when connecting additional enerchips to vchg.) v dd = 2.5v to 5.5v, t a = -20 oc to +70oc characteristic symbol condition min max units enable=v dd to charge pump active t cpon enable to 3rd charge pump pulse, v dd =3.3v 60 80 s enable falling to charge pump inactive t cpoff - 0 1 s charge pump frequency f cp - 120 khz (1) charge pump resistance r cp delta v bat , for i bat charging current of 1a to 100a c fly =0.1f, c bat =1.0f 150 300 ? v chg output voltage v cp c fly =0.1f, c bat =1.0f, i out =1a, temp=+25oc 4.075 4.125 v v chg temp. coeffcient t ccp i out =1a, temp=+25oc -2.0 -2.4 mv/oc charge pump current drive i cp i bat =1ma c fly =0.1f, c bat =1.0f 1.0 - ma charge pump on voltage v enable enable=v dd 2.5 - v (1) f cp = 1/t cpper additional characteristics t a = -20 oc to +70oc characteristic symbol condition limits units min max v bat cutoff threshold v batco i out =1a 2.75 3.25 v cutoff temp. coeffcient t cco - +1 +2 mv/oc v bat cutoff delay time t cooff v bat from 40mv above to 20mv below v batco i out =1a 40 - ms note: all specifcations contained within this document are subject to change without notice cbc34813 enerchip? rtc preliminary
?2013 cymbet corporation ? tel: +1-763-633-1780 ? www.cymbet.com ds-72-38 v.01 page 9 of 9 cymbet, the cymbet logo, and enerchip are cymbet corporation trademarks 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, ftness 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 confrm 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. 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 cbc34813 enerchip? rtc preliminary
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