bq3287E/bq3287EA Real-Time Clock (RTC) Module Features ➤ Direct clock/calendar replacement for IBM ® AT-compatible computers and other applications ➤ Functionally compatible with the DS1287/DS1287A and MC146818A/ MC146818B ➤ 242 bytes of general nonvolatile storage ➤ Calendar in day of the week, day of the month, months, and years with automatic leap-year adjustment ➤ Programmable square wave output ➤ Three individually maskable interrupt event flags: ➤ Provides a 32.768kHz output for power management ➤ System wake-up capability— al arm int e r r upt ac t iv e battery-backup mode ➤ 160 ns cycle time allows fast bus operation ➤ 14 bytes for clock/calendar and control ➤ Time of day in seconds, minutes, and hours 12- or 24-hour format - Optional daylight saving adjustment Pin Connections MOT NC NC AD0 AD1 AD2 AD3 AD4 AD5 AD6 AD7 VSS 1 2 3 4 5 6 7 8 9 10 11 12 24 23 22 21 20 19 18 17 16 15 14 13 Periodic rates from 122µs to 500ms - Time-of-day alarm once per second to once per day - End-of-clock update cycle in ➤ Integral lithium cell and crystal - - ➤ Better than one minute per month clock accuracy General Description The CMOS bq3287E/bq3287EA is a low-power microprocessor peripheral providing a time-of-day clock and 100-year calendar with alarm features and battery operation. O t he r f e a tu re s i n cl u d e th re e maskable interrupt sources, squarewave output, and 242 bytes of gene r al n o n v o l a ti l e s to ra g e. A 32.768kHz output is available for sustaining power-management activities. Wake-up capability is pro- vided by an alarm interrupt, which is active in battery-backup mode. The bq3287EA version is identical to the bq3287E, with the addition of the RAM clear input. The bq3287E is a fully compatible real-time clock for IBM AT-compatible computers and other applications. The bq3287E write-protects the clock, calendar, and storage registers during power failure. The integral backup energy source then maintains data and operates the clock and calendar. As shipped from Benchmarq, the real time clock is turned off to maximize battery capacity for in-system operation. The bq3287E is functionally equivalent to the bq3285E, except the battery (16,20) and crystal pins (2,3) are not accessible. These pins are connected internally to a coin cell and quartz crystal. The coin cell is sized to provide 10 years of data retention and clock operation in the absence of power. For a complete description of features, operating conditions, electrical characteristics, bus timing, and pin descriptions, see the bq3285E data sheet. Pin Names VCC SQW EXTRAM NC/RCL NC INT RST DS NC R/W AS CS 24-Pin DIP Module AD0–AD7 Multiplex address/data input/output MOT CS Chip select input AS Address strobe input DS Data strobe input R/W Read/write input INT Interrupt request output PN3287E1.eps Sept. 1996 C 1 RST Reset input SQW Square wave output EXTRAM Extended RAM enable NC No connect RCL RAM clear input (bq3287EA only) VCC +5V supply VSS Ground bq3287E/bq3287EA Absolute Maximum Ratings Symbol Parameter Value Unit Conditions VCC DC voltage applied on VCC relative to VSS -0.3 to 7.0 V VT DC voltage applied on any pin excluding VCC relative to VSS -0.3 to 7.0 V VT ≤ VCC + 0.3 TOPR Operating temperature 0 to +70 °C Commercial TSTG Storage temperature -40 to +70 °C Commercial TBIAS Temperature under bias -10 to +70 °C Commercial TSOLDER Soldering temperature 260 °C For 10 seconds Note: Permanent device damage may occur if Absolute Maximum Ratings are exceeded. Functional operation should be limited to the Recommended DC Operating Conditions detailed in this data sheet. Exposure to conditions beyond the operational limits for extended periods of time may affect device reliability. Recommended DC Operating Conditions (TA = TOPR) Minimum Typical Maximum Unit VCC Symbol Supply voltage 4.5 5.0 5.5 V VSS Supply voltage 0 0 0 V VIL Input low voltage -0.3 - 0.8 V VIH Input high voltage 2.2 - VCC + 0.3 V Note: Parameter Typical values indicate operation at TA = 25°C. DC Electrical Characteristics (TA = TOPR, VCC = 5V ± 10%) Symbol Parameter Minimum Typical Maximum Unit Conditions/Notes ILI Input leakage current - - ±1 µA VIN = VSS to VCC ILO Output leakage current - - ±1 µA AD0–AD7, INT and SQW in high impedance VOH Output high voltage 2.4 - - V IOH = -1.0 mA VOL Output low voltage - - 0.4 V IOL = 4.0 mA ICC Operating supply current - 7 15 mA VSO Supply switch-over voltage VPFD Power-fail-detect voltage IRCL IMOTH IXTRAM Note: Min. cycle, duty = 100%, IOH = 0mA, IOL = 0mA - 3.0 - V 4.0 4.17 4.35 V Input current when RCL = VSS - - 185 µA Internal 30K pull-up (bq3287EA only) Input current when MOT = VCC - - -185 µA Internal 30K pull-down - - -185 µA Internal 30K pull-down Input current when EXTRAM = VCC Typical values indicate operation at TA = 25°C, VCC = 5V. Sept. 1996 C 2 bq3287E/bq3287EA Power-Down/Power-Up Timing Symbol (TA = TOPR) Parameter Minimum Typical Maximum Unit tF VCC slew from 4.5V to 0V 300 - - µs tR VCC slew from 0V to 4.5V 100 - - µs tCSR CS at VIH after power-up 20 - 200 ms tDR Data-retention and timekeeping time 10 - - years Note: Conditions Internal write-protection period after VCC passes VPFD on power-up. TA = 25°C. Clock accuracy is better than ± 1 minute per month at 25°C for the period of tDR. Caution: Negative undershoots below the absolute maximum rating of -0.3V in battery-backup mode may affect data integrity. Power-Down/Power-Up Timing Sept. 1996 C 3 bq3287E/bq3287EA 24-Pin MT (T-type module) 24-Pin MT (T-Type Module) Inches Millimeters Dimension A Min. Max. Min. Max. 0.360 0.390 9.14 9.91 A1 0.015 - 0.38 - B 0.015 0.022 0.38 0.56 C 0.008 0.013 0.20 0.33 D 1.320 1.335 33.53 33.91 E 0.710 0.740 18.03 18.80 e 0.590 0.620 14.99 15.75 G 0.090 0.110 2.29 2.79 L 0.110 0.130 2.79 3.30 S 0.100 0.120 2.54 3.05 Sept. 1996 C 4 bq3287E/bq3287EA Data Sheet Revision History Change No. Page No. 1 8 Register C, bit 2 2 2 IRCL max. was 275; is now 185. Pull-down = 30K. Value change 2 2 IXTRAM max. was -75; is now -185. Notes: Description Nature of Change Was 0; is na (not affected) Value change Change 1 = Apr. 1994 B “Final” changes from Dec. 1993 A “Preliminary.” Change 2 = Sept. 1996 C changes from April 1994 B. Ordering Information bq3287E MT Temperature: blank = Commercial (0 to +70°C) Package Option: MT = T-type module RAM Clear Option: A = RAM clear on pin 21 no mark = No connect on pin 21 Device: bq3287E Real-Time Clock Module Sept. 1996 C 5 PACKAGE OPTION ADDENDUM www.ti.com 4-Mar-2005 PACKAGING INFORMATION Orderable Device Status (1) BQ3287EAMT ACTIVE 0 1 None Call TI Call TI BQ3287EMT ACTIVE 0 1 None Call TI Call TI Package Type Package Drawing Pins Package Eco Plan (2) Qty Lead/Ball Finish MSL Peak Temp (3) (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) Eco Plan - May not be currently available - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. None: Not yet available Lead (Pb-Free). Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Green (RoHS & no Sb/Br): TI defines "Green" to mean "Pb-Free" and in addition, uses package materials that do not contain halogens, including bromine (Br) or antimony (Sb) above 0.1% of total product weight. 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