DS1374 19-5484 Rev 4 8/10 2 I C, 32-Bit Binary Counter Watchdog RTC with Trickle Charger and Reset Input/Output General Description Features 32-Bit Binary Counter The DS1374 is a 32-bit binary counter designed to contin- uously count time in seconds. An additional counter gen- Second Binary Counter Provides Time-of-Day erates a periodic alarm or serves as a watchdog timer. If Alarm, Watchdog Timer, or NV RAM disabled, this counter can be used as 3 bytes of non- Separate Square-Wave and Interrupt Output Pins volatile (NV) RAM. Separate output pins are provided for 2 I C Serial Interface an interrupt and a square wave at one of four selectable frequencies. A precision temperature-compensated refer- Automatic Power-Fail Detect and Switch Circuitry ence and comparator circuit monitor the status of V to CC Single-Pin Pushbutton Reset Input/Open-Drain detect power failures, provide a reset output, and auto- Reset Output matically switch to the backup supply when necessary. Low-Voltage Operation Additionally, the reset pin is monitored as a pushbutton Trickle-Charge Capability input for externally generating a reset. The device is pro- 2 grammed serially through an I C serial interface. -40C to +85C Operating Temperature Range 10-Pin SOP, 16-Pin SO Available in a Surface-Mount Package with an Integrated Crystal (DS1374C) Applications Underwriters Laboratories (UL) Recognized Portable Instruments Point-of-Sale Equipment Typical Operating Circuit Medical Equipment V CC V CC RPU = t /C Telecommunications r B CRYSTAL RPU RPU V CC V X1 X2 CC SQW SCL CPU SDA DS1374 INT INT PRIMARY V BACKUP BATTERY, RST RST GND RECHARGEABLE N.O. BATTERY, OR PUSHBUTTON SUPER CAPACITOR Pin Configurations appear at the end of the data sheet. RESET Ordering Information PART TEMP RANGE VOLTAGE (V) PIN-PACKAGE TOP MARK** DS1374C-18 -40C to +85C 1.8 16 SO (300 mils) DS1374C-18 DS1374C-3 -40C to +85C 3.0 16 SO (300 mils) DS1374C-3 DS1374C-33 -40C to +85C 3.3 16 SO (300 mils) DS1374C-33 DS1374U-18+ -40C to +85C 1.8 10 SOP DS1374-18 DS1374U-3+ -40C to +85C 3.0 10 SOP DS1374-3 DS1374U-33+ -40C to +85C 3.3 10 SOP DS1374-33 Denotes a RoHS-compliant device that may include lead that is exempt under RoHS requirements. The lead finish is JESD97 category e3, and is compatible with both lead-based and lead-free soldering processes. +Denotes a lead(Pb)-free/RoHS-compliant package. **A anywhere on the top mark denotes a RoHS-compliant package. A + anywhere on the top mark denotes a lead(Pb)-free package. Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com.2 I C, 32-Bit Binary Counter Watchdog RTC with Trickle Charger and Reset Input/Output ABSOLUTE MAXIMUM RATINGS Voltage Range on V Pin Relative to Ground .....-0.3V to +6.0V Junction-to-Case Thermal Resistance ( ) (Note 1) CC JC Voltage Range on SDA or SCL 16-Pin SO .....................................................................23C/W Relative to Ground....................................-0.3V to V + 0.3V 10-Pin SOP.................................................................39C/W CC Junction-to-Ambient Thermal Resistance ( ) (Note 1) Operating Temperature Range ...........................-40C to +85C JA 16-Pin SO .....................................................................73C/W Storage Temperature Range .............................-55C to +125C 10-Pin SOP...............................................................221C/W Lead Temperature (soldering, 10s) .................................+260C Soldering Temperature (reflow) .......................................+260C 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.maxim-ic.com/thermal-tutorial. Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation 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. RECOMMENDED DC OPERATING CONDITIONS (V = V to V , T = -40C to +85C, unless otherwise noted.) (Note 2) CC CC(MIN) CC(MAX) A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS DS1374-33 2.97 3.3 5.50 Supply Voltage V V DS1374-3 2.7 3.0 3.3 CC (Notes 3, 4) DS1374-18 1.71 1.8 1.89 Input Logic 1 V (Note 3) 0.7 x V V + 0.3 V IH CC CC +0.3 x Input Logic 0 V (Note 3) -0.3 V IL V CC Pullup Resistor Voltage (INT, V (Note 3) 5.5 V PU SQW, SDA, SCL), V = 0V CC DS1374-33 2.70 2.88 2.97 Power-Fail Voltage VDS1374-3 2.45 2.6 2.7 V PF (Note 3) DS1374-18 1.51 1.6 1.71 V CC DS1374-33 1.3 3.0 Backup Supply Voltage ( V MAX) V BACKUP (Notes 3, 4, 5) DS1374-3, DS1374-18 1.3 3.0 3.7 2 DS1374