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 reset externally. 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
Applications/Uses
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 2099
Two Time-of-Day Alarms
Programmable Square-Wave Output
4MHz SPI Bus Supports Modes 1 and 3
Digital Temp Sensor Output: ±3°C Accuracy
Register for Aging Trim
Active-Low RST Input/Output
300-Mil, 20-Pin SO Package
Underwriters Laboratory (UL) Recognized
GPS
Servers
Telematics
Utility Power Meters
Key Specifications:
Oscillator Modules
Part Number
Frequency
Oscillator Type
Tuning Adjustment Type
Frequency Output Type
Freq. Stability vs. Temp. @0 to +40°C (±ppm)
Freq. Stab. vs.Temp. @-40 to 0/ +40 to 85°C (±ppm)
Notes: **This pricing is BUDGETARY, for comparing similar parts. Prices are in
U.S. dollars and subject to change. Quantity pricing may vary
substantially and international prices may differ due to local
duties, taxes, fees, and exchange rates. For volume-specific prices
and delivery, please see the price and availability page
or contact an authorized distributor.
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