Extremely Accurate I2C-Integrated RTC/TXO/Crystal

www.DataSheet4U.com Rev 2; 6/05 Extremely Accurate I2C-Integrated RTC/TCXO/Crystal General Description The DS3231 is a low-cost, extremely accurate I2C realtime clock (RTC) with an integrated temperaturecompensated crystal oscillator (TCXO) and crystal. The device incorporates a battery input, and maintains accurate timekeeping when main power to the device is interrupted. The integration of the crystal resonator enhances the long-term accuracy of the device as well as reduces the piece-part count in a manufacturing line. The DS3231 is available in commercial and industrial temperature ranges, and is offered in a 16-pin, 300-mil SO package. The RTC maintains seconds, minutes, hours, day, date, month, and year information. The date at the end of the month is automatically adjusted for months with fewer than 31 days, including corrections for leap year. The clock operates in either the 24-hour or 12-hour format with an AM/PM indicator. Two programmable time-ofday alarms and a programmable square-wave output are provided. Address and data are transferred serially through an I2C bidirectional bus. A precision temperature-compensated voltage reference and comparator circuit monitors the status of VCC to detect power failures, to provide a reset output, and to automatically switch to the backup supply when necessary. Additionally, the RST pin is monitored as a pushbutton input for generating a reset externally. Features ♦ Accuracy ±2ppm from 0°C to +40°C ♦ Accuracy ±3.5ppm from -40°C to +85°C ♦ Battery Backup Input for Continuous Timekeeping ♦ Operating Temperature Ranges Commercial: 0°C to +70°C Industrial: -40°C to +85°C ♦ Low-Power Consumption ♦ Real-Time Clock Counts Seconds, Minutes, Hours, Day, Date, Month, and Year with Leap Year Compensation Valid Up to 2100 ♦ Two Time-of-Day Alarms ♦ Programmable Square-Wave Output ♦ Fast (400kHz) I2C Interface ♦ 3.3V Operation ♦ Digital Temp Sensor Output: ±3°C Accuracy ♦ Register for Aging Trim ♦ RST Input/Output ♦ UL Recognized DS3231 Ordering Information PART DS3231S DS3231SN DS3231S+ DS3231SN+ TEMP RANGE 0°C to +70°C -40°C to +85°C 0°C to +70°C -40°C to +85°C PIN-PACKAGE 16 SO 16 SO 16 SO 16 SO TOP MARK DS3231 DS3231N DS3231+ DS3231N+ Applications Servers Telematics Utility Power Meters GPS Pin Configuration appears at end of data sheet. +Denotes lead-free Typical Operating Circuit VCC VCC RPU = tR/CB RPU RPU VCC SCL CPU SDA RST PUSHBUTTON RESET N.C. N.C. N.C. N.C. INT/SQW 32kHz VBAT N.C. N.C. N.C. N.C. VCC DS3231 GND Purchase of I2C components from Maxim Integrated Products, Inc., or one of its sublicensed Associated Companies, conveys a license under the Philips I2C Patent Rights to use these components in an I2C system, provided that the system conforms to the I2C Standard Specification as defined by Philips. ______________________________________________ Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. Extremely Accurate I2C-Integrated RTC/TCXO/Crystal DS3231 ABSOLUTE MAXIMUM RATINGS Voltage Range on VCC, VBAT, 32kHz, SCL, SDA, RST, INT/SQW Relative to Ground.............................-0.3V to +6.0V Operating Temperature Range (noncondensing) .............................................-40°C to +85°C Junction Temperature ......................................................+125°C Storage Temperature Range ...............................-40°C to +85°C Lead Temperature (Soldering, 10s).....................................................+260°C/10s Soldering Temperature....................................See the Handling, PC Board Layout, and Assembly section. 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 (TA = TMIN to TMAX, unless otherwise noted.) (Notes 1, 2) PARAMETER Supply Voltage Logic 1 Input SDA, SCL Logic 0 Input SDA, SCL Pullup Voltage (SDA, SCL, 32kHz, INT/SQW) SYMBOL VCC VBAT VIH VIL VPU VCC = 0V CONDITIONS MIN 2.3 2.3 0.7 x VCC -0.3 TYP 3.3 3.0 MAX 5.5 5.5 VCC + 0.3 +0.3 x VCC 5.5V UNITS V V V V V ELECTRICAL CHARACTERISTICS (VCC = 2.3V to 5.5V, VCC > VBAT, TA = TMIN to TMAX, unless otherwise noted.) (Typical values are at VCC = 3.3V, VBAT = 3.0V, and TA = +25°C, unless otherwise noted.) (Notes 1, 2) PARAMETER Active Supply Current SYMBOL ICCA (Notes 3, 4) I2C bus inactive, 32kHz output on, SQW output off (Note 4) I2C bus inactive, 32kHz output on, SQW output off CONDITIONS VCC = 3.63V VCC = 5.5V VCC = 3.63V VCC = 5.5V VCC = 3.63V VCC = 5.5V 2.45 IOL = 3mA IOL = 1mA Output high impedance -1 -1 RST high impedance (Note 5) -200 25 0 2.575 MIN TYP MAX 200 300 110 µA 170 575 650 2.70 0.4 0.4 +1 +1 +10 100 µA V V V µA µA µA nA UNITS µA Standby Supply Current ICCS Temperature Conversion Current Power-Fail Voltage Logic 0 Output, 32kHz, INT/SQW, SDA Logic 0 Output, RST Output Leakage Current 32kHz, INT/SQW, SDA Input Leakage SCL RST Pin I/O Leakage VBAT Leakage Current (VCC Active) ICCSCONV VPF VOL VOL ILO ILI IOL IBATLKG 2 _____________________________________________________________________ Extremely Accurate I2C-Integrated RTC/TCXO/Crystal ELECTRICAL CHARACTERISTICS (continued) (VCC = 2.3V to 5.5V, VCC > VBAT, TA = TMIN to TMAX, unless otherwise noted.) (Typical values are at VCC = 3.3V, VBAT = 3.0V, and TA = +25°C, unless otherwise noted.) (Notes 1, 2) PARAMETER Output Frequency Frequency Stability vs. Temperature (Commercial) SYMBOL fOUT ∆f/fOUT CONDITIONS VCC = 3.3V or VBAT = 3.3V VCC = 3.3V or VBAT = 3.3V, aging offset = 00h VCC = 3.3V or VBAT = 3.3V, aging offset = 00h 0°C to +40°C >40°C to +70°C -40°C to <0°C 0°C to +40°C >40°C to +85°C 1 -40°C Trim Register Frequency Sensitivity per LSB Temperature Accuracy Crystal Aging ∆f/LSB Specified at: +25°C +70°C +85°C Temp ∆f/f0 VCC = 3.3V or VBAT = 3.3V After reflow, not production tested First year 0–10 years -3 ±1.0 ±5.0 0.7 0.1 0.4 0.8 +3 °C ppm ppm MIN TYP 32.768 ±2 ppm ±3.5 ±3.5 ±2 ±3.5 ppm/V ppm MAX UNITS kHz DS3231 Frequency Stability vs. Temperature (Industrial) Frequency Stability vs. Voltage ∆f/fOUT ∆f/V ELECTRICAL CHARACTERISTICS (VCC = 0V, VBAT = 2.3V to 5.5V, TA = TMIN to TMAX, unless otherw.ise noted.) (Note 1) PARAMETER Active Battery Current SYMBOL IBATA CONDITIONS EOSC = 0, BBSQW = 0, SCL = 400kHz (Note 4) EOSC = 0, BBSQW = 0, EN32kHz = 1, SCL = SDA = 0V or SCL = SDA = VBAT (Note 4) EOSC = 0, BBSQW = 0, SCL = SDA = 0V or SCL = SDA = VBAT VBAT = 3.63V VBAT = 5.5V VBAT = 3.63V VBAT = 5.5V VBAT = 3.63V VBAT = 5.5V 0.84 1.0 MIN TYP MAX 70 150 3.0 µA 3.5 575 µA 650 100 nA UNITS µA Timekeeping Battery Current IBATT Temperature Conversion Current Data-Retention Current IBATTC IBATTDR EOSC = 1, SCL = SDA = 0V, +25°C _____________________________________________________________________ 3 Extremely Accurate I2C-Integrated RTC/TCXO/Crystal DS3231 AC ELECTRICAL CHARACTERISTICS (VCC = VCC(MIN) to VCC(MAX) or VBAT = VBAT(MIN) to VBAT(MAX), VBAT > VCC, TA = TMIN to TMAX, unless otherwise noted.) (Note 1) PARAMETER SCL Clock Frequency Bus Free Time Between STOP and START Conditions Hold Time (Repeated) START Condition (Note 6) Low Period of SCL Clock High Period of SCL Clock Data Hold Time (Notes 7, 8) Data Setup Time (Note 9) Start Setup Time Rise Time of Both SDA and SCL Signals (Note 10) Fall Time of Both SDA and SCL Signals (Note 10) Setup Time for STOP Condition Capacitive Load for Each Bus Line (Note 10) Capacitance for SDA, SCL Pulse Width of Spikes That Must Be Suppressed by the Input Filter Pushbutton Debounce Reset Active Time Oscillator Stop Flag (OSF) Delay Temperature Conversion Time SYMBOL fSCL tBUF tHD:STA tLOW tHIGH tHD:DAT tSU:DAT tSU:STA tR tF tSU:STO CB CI/O tSP PBDB tRST tOSF tCONV (Note 11) 10 30 250 250 100 125 200 Fast mode Standard mode Fast mode Standard mode Fast mode Standard mode Fast mode Standard mode Fast mode Standard mode Fast mode Standard mode Fast mode Standard mode Fast mode Standard mode Fast mode Standard mode Fast mode Standard mode Fast mode Standard mode CONDITIONS MIN 100 0 1.3 4.7 0.6 4.0 1.3 4.7 0.6 4.0 0 0 100 250 0.6 4.7 20 + 0.1CB 20 + 0.1CB 0.6 4.7 400 300 1000 300 300 0.9 0.9 TYP MAX 400 100 UNITS kHz µs µs µs µs µs ns µs ns ns µs pF pF ns ms ms ms ms POWER-SWITCH CHARACTERISTICS (TA = TMIN to TMAX) PARAMETER VCC Fall Time; VPF(MAX) to VPF(MIN) VCC Rise Time; VPF(MIN) to VPF(MAX) Recovery at Power-Up SYMBOL tVCCF tVCCR tREC (Note 12) CONDITIONS MIN 300 0 250 300 TYP MAX UNITS µs µs ms 4 _____________________________________________________________________ Extremely Accurate I2C-Integrated RTC/TCXO/Crystal Pushbutton Reset Timing RST DS3231 PBDB tRST Power-Switch Timing VCC VPF(MAX) VPF VPF(MIN) VPF tVCCF tVCCR tREC RST _____________________________________________________________________ 5 Extremely Accurate I2C-Integrated RTC/TCXO/Crystal DS3231 Data Transfer on I2C Serial Bus SDA tBUF tLOW tR tF tHD:STA tSP SCL tHD:STA STOP START tHD:DAT tHIGH tSU:DAT REPEATED START tSU:STA tSU:STO Limits at -40°C are guaranteed by design and not production tested. All voltages are referenced to ground. ICCA—SCL clocking at max frequency = 400kHz. Current is the averaged input current, which includes the temperature conversion current. The RST pin has an internal 50kΩ (nominal) pullup resistor to VCC. After this period, the first clock pulse is generated. A device must internally provide a hold time of at least 300ns for the SDA signal (referred to the VIH(MIN) of the SCL signal) to bridge the