General DescriptionThe low-voltage serial-peripheral interface (SPI™)DS1390/DS1391/DS1394 and the low-voltage 3-wireDS1392/DS1393 real-time clocks (RTCs) are clocks/cal-endars that provide hundredths of a second, seconds,minutes, hours, day, date, month, and year information.The date at the end of the month is automaticallyadjusted for months with fewer than 31 days, includingcorrections for leap year. The clock operates in eitherthe 24-hour or 12-hour format with an AM/PM indicator.One programmable time-of-day alarm is provided. Atemperature-compensated voltage reference monitorsthe status of VCCand automatically disables the businterface and switches to the backup supply if a powerfailure is detected. On the DS1390, a single open-drainoutput provides a CPU interrupt or a square wave atone of four selectable frequencies. The DS1391replaces the SQW/INT pin with a RST output/debounced input. The DS1390, DS1391, and DS1394 are programmedserially through an SPI-compatible, bidirectional bus.The DS1392 and DS1393 communicate over a 3-wireserial bus, and the extra pin is used for either a sepa-rate interrupt pin or a RST output/debounced input.All five devices are available in a 10-pin µSOP package,and are rated over the industrial temperature range.ApplicationsHand-Held DevicesGPS/Telematics DevicesEmbedded Time StampingMedical DevicesFeatures♦ Real-Time Clock Counts Hundredths of Seconds,Seconds, Minutes, Hours, Day, Date, Month, andYear with Leap-Year Compensation Valid Up to2100♦ Output Pin Configurable as Interrupt or SquareWave with Programmable Frequency of32.768kHz, 8.192kHz, 4.096kHz, or 1Hz(DS1390/DS1393/DS1394 Only)♦ One Time-of-Day Alarm♦ Power-Fail Detect and Switch Circuitry♦ Reset Output/Debounced Input (DS1391/DS1393)♦ Separate SQW and INT Output (DS1392)♦ Trickle-Charge Capability♦ SPI Supports Modes 0 and 2 (DS1394)♦ SPI Supports Modes 1 and 3 (DS1390/DS1391)♦ 3-Wire Interface (DS1392/DS1393)♦ 4MHz at 3.0V and 3.3V♦ 1MHz at 1.8V♦ Three Operating Voltages: 1.8V ±5%, 3.0V ±10%,and 2.97 to 5.5V (DS1394: 3.3V ±10%)♦ Industrial Temperature Range: -40°C to +85°C♦ Underwriters Laboratories (UL) RecognizedDS1390–DS1394Low-Voltage SPI/3-Wire RTCs withTrickle Charger______________________________________________Maxim Integrated Products1Ordering Information19-4898; Rev 3; 8/09For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,or visit Maxim’s website at www.maxim-ic.com.Typical Operating Circuits and Pin Configurations appear atend of the data sheet.Note: All devices are rated for the -40°C to +85°C operatingtemperature range.+Denotes a lead(Pb)-free/RoHS-compliant package./V denotes an automotive qualified part.†A “+” anywhere on the top mark denotes a lead(Pb)-free/RoHS-compliant package.rr = Revision code on second line of top mark.PARTTYP OPERATING VOLTAGE (V)PIN-PACKAGETOP MARK†DS1390U-18+ 1.8 10 μSOP 1390 rr-18 DS1390U-3+ 3.0 10 μSOP 1390 rr-3 DS1390U-33+ 3.3 10 μSOP 1390 rr-33 DS1390U-33/V+ 3.3 10 μSOP 1390 rr-33 DS1391U-18+ 1.8 10 μSOP 1391 rr-18 DS1391U-3+ 3.0 10 μSOP 1391 rr-3 DS1391U-33+ 3.3 10 μSOP 1391 rr-33 DS1392U-18+ 1.8 10 μSOP 1393 rr-18 DS1392U-3+ 3.0 10 μSOP 1392 rr-3 DS1392U-33+ 3.3 10 μSOP 1392 rr-33 DS1393U-18+ 1.8 10 μSOP 1393 rr-18 DS1393U-3+ 3.0 10 μSOP 1393 rr-3 DS1393U-33+ 3.3 10 μSOP 1393 rr-33 DS1394U-33+ 3.3 10 μSOP 1394 rr-33 SPI is a trademark of Motorola, Inc.DS1390–DS1394Low-Voltage SPI/3-Wire RTCs withTrickle Charger2 _____________________________________________________________________ABSOLUTE MAXIMUM RATINGSRECOMMENDED DC OPERATING CONDITIONS(VCC= VCC(MIN)to VCC(MAX), TA= -40°C to +85°C, unless otherwise noted. Typical values are at nominal supply voltage and TA= +25°C,unless otherwise noted.) (Note 1)Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functionaloperation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure toabsolute maximum rating conditions for extended periods may affect device reliability.Voltage Range on VCCPin Relative to Ground .....-0.3V to +6.0VVoltage Range on Inputs Relative to Ground ...............................................-0.3V to (VCC+ 0.3V)Operating Temperature Range ...........................-40°C to +85°CStorage Temperature Range .............................-55°C to +125°CSoldering Temperature...........................Refer to the IPC/JEDEC J-STD-020 Specification.PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITSDS139x-33 2.97 3.3 5.50 DS139x-3 2.7 3.0 3.3 Supply Voltage (Note 2) VCCDS139x-18 1.71 1.8 1.89 VLogic 1 VIH (Note 2) 0.7 x VCCVCC + 0.5VLogic 0 VIL (Note 2) -0.3 +0.3 x VCCVSupply Voltage, Pullup SQW/INT, SQW, INT, VCC = 0V VPU (Note 2) 5.5 V -33 1.3 3.0 VCC(MAX)-3 1.3 3.0 3.7 VBACKUP Voltage (Note 2) VBACKUP-18 1.3 3.0 3.7 V-33 2.70 2.88 2.97 -3 2.45 2.6 2.70 Power-Fail Voltage (Note 2) VPF-18 1.51 1.6 1.71 VR1 (Notes 3, 4) 250 R2 (Notes 3, 5) 2000 Trickle-Charge Current-Limiting Resistors R3 (Notes 3, 6) 4000 Input Leakage ILI (Note 7) -1 +1 μA I/O Leakage ILO (Note 8) -1 +1 μA RST Pin I/O Leakage ILORST (Note 9) -200 +10 μA -33, -3 (VOH = 0.85 x VCC) -1 DOUT Logic 1 Output IOHDOUT-18 (VOH = 0.80 x VCC) 0.750 mA -33, -3 (VOL = 0.15 x VCC) 3 DOUT Logic 0 Output IOHDOUT-18 (VOL = 0.20 x VCC) 2 mA VCC > 1.71V; VOL = 0.4V 3.0 mA Logic 0 Output (DS1390/DS1393/DS1394 SQW/INT; DS1392 SQW, INT;DS1391/DS1393 RST)IOLSIR1.3V < VCC < 1.71V; VOL = 0.4V 250 μA -33 2 -3 2 mA VCC Active Supply Current (Note 10) ICCA-18 500 μADS1390–DS1394Low-Voltage SPI/3-Wire RTCs withTrickle Charger_____________________________________________________________________ 3RECOMMENDED DC OPERATING CONDITIONS (continued)(VCC= VCC(MIN)to VCC(MAX), TA= -40°C to +85°C, unless otherwise noted. Typical values are at nominal supply voltage and TA= +25°C,unless otherwise noted.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS-33 115 175 -3 80 125 VCC Standby Current (Note 11) ICCS-18 60 100 μA VBACKUP Leakage Current (VBACKUP = 3.7V, VCC = VCC(MAX))IBACKUPLKG 15 100 nA DC ELECTRICAL CHARACTERISTICS(VCC= 0V, VBACKUP= 3.7V, TA= -40°C to +85°C, unless otherwise noted.)