BQ4802YPWR

BQ4802YPWR FEATURES

BQ4802YPWR DESCRIPTION

The bq4802Y/bq4802LY real-time clock is a low-powermicroprocessor peripheral that integrates a time-of-day clock, a century-based calendar, and a CPU super-visor, with package options including a 28-pin SOIC,TSSOP, or SNAPHAT that requires the bq48SH-28x6to complete the two-piece module. The bq4802Y/bq4802LY is ideal for fax machines, copiers, industrialcontrol systems, point-of-sale terminals, data loggers,and computers.TO µPREAD/WRITECONTROLFROM µPFROM µPI/O LINECEOUTOEWEVOUTVSSCEINCSINTWDORST32.768 kHzCRYSTALA0–A3DQ0–DQ7WDIADDRESS BUSDATA BUSBCX1X2DQ0–DQ7DATA BUSFROMADDRESSDECODELOGIC3 VLITHIUMCELLbq4802A0–A3ADDRESS BUS62256LCMOS SRAMOE WRVCCCE5 kΩVCCTYPICAL APPLICATIONPRODUCTION DATA information is current as of publication date. Productsconform to specifications per the terms of Texas Instruments standard warranty.Production processing does not necessarily include testing of all parameters.Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instrumentssemiconductor products and disclaimers thereto appears at the end of this data sheet.www.ti.comCopyright  2002, Texas Instruments Incorporated

BQ4802YPWR APPLICATIONS

BQ4802YPWR DESCRIPTION (CONTINUED)

The bq4802Y/bq4802LY provides direct connectionsfor a 32.768-kHz quartz crystal and a 3-V backupbattery. Through the use of the conditional chip enableoutput (CEOUT) and battery voltage output (VOUT) pins,the bq4802Y/bq4802LY can write-protect and makenon- volatile external SRAMs. The backup cell powersthe real-time clock and maintains SRAM information inthe absence of system voltage. The crystal and batteryare contained within the modules for a more integratedsolution.The bq4802Y/bq4802LY contains a temperature-compensated reference and comparator circuit thatmonitors the status of its voltage supply. When thebq4802Y/bq4802LYdetectsanout-of-tolerancecondition, it generates an interrupt warning and sub-sequently a microprocessor reset. The reset staysactive for 200 ms after VCC rises within tolerance, toallow for power supply and processor stabilization. Thereset function also allows for an external push-buttonoverride.ORDERING INFORMATIONTOPERATIONDEVICESSYMBOLTAOPERATIONSOIC(1) (DW)TSSOP(1) (PW)SNAPHAT(1)(2)(3) (DSH)SYMBOL0°C to70°C5 Vbq4802YDWbq4802YPWbq4802YDSHbq4802Y0°C to +70°C3.3 Vbq4802LYDWbq4802LYPWbq4802LYDSHbq4802LY(1) The DW, PW and DSH packages are available taped and reeled. Add an R suffix to the device type (i.e., bq4802YDWR).(2) The DSH package is available taped only.(3) The bq48SH–28x6 should be ordered to complete the SNAPHAT module and is the same part number for both 3.3-V and 5-V modules.CAUTION: Wave soldering of DSH package may cause damage to SNAPHAT sockets.ABSOLUTE MAXIMUM RATINGSover operating free-air temperature range unless otherwise noted(1)bq4802Ybq4802LYInput voltage range, VCC, VT (VT ≤ VCC +0.3)–0.3 V to 6.0 VOperating temperature range, TJ0°C to 70°CStorage temperature range, Tstg–55°C to 125°CTemperature under bias, TJbias–40°C to 85°CLead temperature 1,6 mm (1/16 inch) from case for 10 seconds300°C(1) Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, andfunctional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is notimplied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.RECOMMENDED OPERATING CONDITIONSMINMAXUNITSupply voltage Vbq4802Y4.55.5VSupply voltage, VCCbq4802LY2.73.6VInput low voltage, VIL–0.30.8VInput high voltage, VIH2.2VCC + 0.3VBackup cell voltage, VBC2.44.0VPush button reset input low, VBC–0.30.4VPush button reset input high, VPBRH2.2VCC + 0.3V