DS3234:Extremely Accurate SPI Bus RTC with Integrated Crystal and SRAM

Completely Integrated, Accurate Timing Solution Provides Better than ±2.0 Minutes per Year Accuracy Over the Industrial Temperature Range and Requires No User Calibration

The DS3234 is a low-cost, extremely accurate SPI™ bus real-time clock (RTC) with an integrated temperature-compensated crystal oscillator (TCXO) and crystal. The DS3234 incorporates a precision, temperature-compensated voltage reference and comparator circuit to monitor VCC. When VCC drops below the power-fail voltage (VPF), the device asserts the active-low RST output and also disables read and write access to the part when VCC drops below both VPF and VBAT. The active-low RST pin is monitored as a pushbutton input for generating a µP reset. The device switches to the backup supply 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 DS3234 is available in commercial and industrial temperature ranges, and is offered in an industry-standard 300-mil, 20-pin SO package. The DS3234 also integrates 256 bytes of battery-backed SRAM. In the event of main power loss, the contents of the memory are maintained by the power source connected to the VBAT pin. 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 active-low AM/PM indicator. Two programmable time-of-day alarms and a programmable square-wave output are provided. Address and data are transferred serially by an SPI bidirectional bus.

Key Features
  • Highly Accurate RTC with Integrated Crystal and SRAM Completely Manages All Timekeeping Functions
    • Accuracy ±2ppm from 0°C to +40°C
    • Accuracy ±3.5ppm from -40°C to +85°C
    • Real-Time Clock Counts Seconds, Minutes, Hours, Day, Date, Month, and Year, with Leap Year Compensation Valid Up to 2099
    • Digital Temp Sensor Output: ±3°C Accuracy
    • Register for Aging Trim
    • Active-Low RST Input/Output
    • Two Time-of-Day Alarms
    • Programmable Square-Wave Output
  • Simple Serial Interface Connects to Most Microcontrollers
    • 4MHz SPI Bus Supports Modes 1 and 3
  • Battery-Backup Input for Continuous Timekeeping
    • Low Power Operation Extends Battery Backup Run Time
  • Operating Temperature Ranges: Commercial: 0°C to +70°C, Industrial: -40°C to +85°C
  • 300-Mil, 20-Pin SO Package
  • Underwriters Laboratories® (UL) Recognized
DS3234: Typical Operating Circuit
DS3234: Typical Operating Circuit
Applications/Uses
  • GPS
  • Servers
  • Telematics
  • Utility Power Meters
DataSheet
titleDownload file
DS3234 Data SheetDS3234.pdf
Parametrics
Part NumberFreq.Osc. TypeTuning Adjustment TypeFreq. Output TypeFrequency Stability
(±ppm/yr)
Frequency Stability
(±ppm/yr)
Frequency Stability
(±ppm/yr)
Frequency Stability
(±ppm)
VSUPPLY
(V)
Package/PinsBudgetary
Price
0 to +40°C-40 to 0°C/ +40 to +85°Cvs. VCCvs. AgingSee Notes
DS323432.768kHzTCXODigitalCMOS Push-Pull23.51 (typ)5 (0-10 Years)2.0 to 5.5
2.7 to 5.5
SOIC/20$4.40 @1k

Part NumberInterfaceVSUPPLY
(V)
Time Keeping Current
(nA)
Memory TypeMemory Size
(Bytes)
Time of Day AlarmsIntegrated ResonatorFunctionsPackage/PinsBudgetary
Price
typSee Notes
DS3234SPI2.0 to 5.5
2.7 to 5.5
1500NV SRAM2562XTALRTCSOIC/20$4.40 @1k
Quality and Environmental Data
Related Products
  • DS3232:Extremely Accurate I²C RTC with Integrated Crystal and SRAM
  • DS4077:50MHz to 122.88MHz VCXO
  • DS3231:Extremely Accurate I²C-Integrated RTC/TCXO/Crystal
  • DS32KHZ:32.768kHz Temperature-Compensated Crystal Oscillator
Ordering Information
Part NumberStatusRecommended ReplacementPackageTempRoHS
DS3234S#ActiveSOIC,;20 pin;SOIC (;0°C to +70°C
DS3234SN#ActiveSOIC,;20 pin;SOIC (;-40°C to +85°C
DS3234.pdf DS3234
DS3234.pdf DS3234
DS3234.pdf DS3234
Tips for Writing Bulletproof Real-Time Clock Control Code DS3234
Industry Turns to MEMS for Accurate Real-Time Clocks DS3234
State Machine Logic in Binary-Coded Decimal (BCD)-Formatted Real-Time Clocks DS3234
Implementing Flawless Designs with Accurate I²C Real-Time Clocks DS3234
Interfacing a DS3234 Extremely Accurate SPI-Bus Real-Time Clock (RTC) to a Motorola Digital Signal Processor (DSP) DS3234
Selecting a Backup Source for Real-Time Clocks DS3234
Interfacing an SPI RTC with a Motorola DSP DS3234
Interfacing an SPI-Interface RTC with a PIC Microcontroller DS3234
Design Considerations for Maxim Real-Time Clocks DS3234
Interfacing SPI Real-Time Clocks (RTCs) with a Microcontroller DS3234
Crystal Considerations with Maxim Real-Time Clocks (RTCs) DS3234
DS3234.pdf DS3234
DS3234.pdf DS3234