2 DS1308 Low-Current I C RTC with 56-Byte NV RAM General Description Benefits and Features The DS1308 serial real-time clock (RTC) is a low-power, Compatible with Crystal ESR Up to 100k Allows a full binary-coded decimal (BCD) clock/calendar plus Crystal to be Optimized for Cost and Space 56 bytes of NV RAM. Address and data are transferred Low-Power Operation Extends Battery Backup Run Time 2 serially through an I C interface. The clock/calendar Low Timekeeping Current of 250nA (typ) provides seconds, minutes, hours, day, date, month, Automatic Power-Fail Detect and Switch Circuitry and year information. The end of the month date is auto- Completely Manages All Timekeeping Functions matically adjusted for months with fewer than 31 days, Real-Time Clock Counts Seconds, Minutes, Hours, including corrections for leap year. The clock operates Date of the Month, Month, Day of the Week, and in either the 24-hour or 12-hour format with an AM/PM Year with Leap-Year Compensation Valid Up to 2400 indicator. The DS1308 has a built-in power-sense circuit External Clock Source for Synchronization Clock that detects power failures and automatically switches to Reference (e.g., 32kHz, 50Hz/60Hz Powerline, the backup supply, maintaining time and date operation. GPS 1PPS) 56-Byte, Battery-Backed, General-Purpose RAM Applications with Unlimited Writes Handhelds (GPS, POS Terminal) Programmable Square-Wave Output Signal Consumer Electronics (Set-Top Box, Digital Simple Serial Port Interfaces with Most Microcontrollers Recording, Network Appliance) 2 I C Serial Interface Office Equipment (Fax/Printer, Copier) Industrial Temperature Range: -40C to +85C Medical (Glucometer, Medicine Dispenser) Supports Operation in a Wide Range of Applications Telecommunications (Router, Switcher, Server) Underwriters Laboratories (UL ) Recognized Other (Utility Meter, Vending Machine, Thermostat, Modem) Typical Operating Circuit V V CC CC R R R PU PU PU V CC SCL X1 SDA SQW/CLKIN X2 CPU DS1308 V BAT GND Ordering Information appears at end of data sheet. UL is a registered trademark of Underwriters Laboratories Inc. 19-6353 Rev 3 4/152 DS1308 Low-Current I C RTC with 56-Byte NV RAM Absolute Maximum Ratings (All voltages relative to ground.) Junction Temperature Maximum .....................................+150NC Voltage Range on V or V ...........................-0.3V to +6.0V Storage Temperature Range ............................ -55NC to +125NC CC BAT Voltage on Any Non-Power Pin ................ -0.3V to (V + 0.3V) Lead Temperature (soldering, 10s) ................................+300NC CC Operating Temperature Range .......................... -40NC to +85NC Soldering Temperature (reflow) ......................................+260NC Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional opera- tion of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Package Thermal Characteristics (Note 1) FSOP Junction-to-Ambient Thermal Resistance (B ) .....206.3NC/W Junction-to-Case Thermal Resistance (B ) ...............42NC/W JA JC Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer board. For detailed information on package thermal considerations, refer to www.maximintegrated.com/thermal-tutorial. Recommended Operating Conditions (T = -40NC to +85NC, unless otherwise noted.) (Note 2) A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS DS1308-18 1.71 1.8 5.5 Operating Voltage Range V DS1308-3 2.7 3.0 5.5 V CC DS1308-33 3.0 3.3 5.5 Battery Voltage V 1.3 5.5 V BAT 0.7 x V + CC Logic 1 Input V V IH V 0.3 CC 0.3 x Logic 0 Input V -0.3 V IL V CC DC Electrical Characteristics (V = V to V , V = V to V , T = -40NC to +85NC, unless otherwise noted.) (Note 2) CC CCMIN CCMAX BAT BATMIN BATMAX A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Power-Supply Active Current I f = 400kHz 325 FA CCA SCL (Note 3) -33: V = 3.63V 125 CC -3: V = 3.3V 125 Power-Supply Standby Current CC I FA CCS (Note 4) -18: V = 1.89V 100 CC V = V 200 CC CCMAX Battery Leakage Current I V R V -100 25 +100 nA BATLKG CC PF Input Leakage (SCL) I V = 0V to V -0.1 +0.1 FA I IN CC 2 I/O Leakage (SDA, SQW/CLKIN) I I C bus inactive, ECLK = 1 -0.1 +0.1 FA IO V R V 3.0 mA Output Logic 0 (SDA, SQW/ CC CCMIN I OL CLKIN), V = 0.4V OL V R 1.3V R V + 0.2V 250 FA BAT CC -33 2.70 2.82 3.00 Power-Fail Trip Point V -3 2.45 2.55 2.70 V PF -18 1.45 1.62 1.70 Maxim Integrated 2 www.maximintegrated.com