DS1388:I²C RTC/Supervisor with Trickle Charger and 512 Bytes EEPROM

The DS1388 I²C real-time clock (RTC), supervisor, and EEPROM is a multifunction device that provides a clock/calendar, programmable watchdog timer, power-supply monitor with reset, and 512 bytes of EEPROM. The clock provides hundredths of seconds, seconds, minutes, and hours, and operates in 24-hour or 12-hour format with an AM/PM indicator. The calendar provides 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. A watchdog timer provides a reset for an unresponsive microprocessor. It is programmable in 10ms intervals from 0.01 to 99.99 seconds. A temperature-compensated voltage reference and comparator circuit monitors the status of VCC. If a primary power failure is detected, the device automatically switches to the backup supply and drives the reset output to the active state. The backup supply maintains time and date operation in the absence of VCC. When VCC returns to nominal levels, the reset is held low for a period to allow the power supply and processor to stabilize. The device also has a pushbutton reset controller, which debounces a reset input signal. The device is accessed through an I²C serial interface.

Key Features
  • Fast (400kHz) I²C Interface
  • RTC Counts Hundredths of Seconds, Seconds, Minutes, Hours, Day, Date, Month, and Year with Leap Year Compensation Valid Up to 2100
  • Programmable Watchdog Timer
  • Automatic Power-Fail Detect and Switch Circuitry
  • Reset Output with Pushbutton Reset Input Capability
  • 512 x 8 Bits of EEPROM
  • Integrated Trickle-Charge Capability for Backup Supply
  • Three Operating Voltages: 5.0V, 3.3V, and 3.0V
  • Low Timekeeping Voltage Down to 1.3V
  • -40°C to +85°C Temperature Range
DS1388: Typical Operating Circuit
DS1388: Typical Operating Circuit
Applications/Uses
  • Network-Interface Cards
  • Point-of-Sale Equipment
  • Portable Instrumentation
  • Wireless Equipment
DataSheet
titleDownload file
DS1388 Data SheetDS1388.pdf
Parametrics
Part NumberInterfaceVSUPPLY
(V)
Time Keeping Current
(nA)
CL
(pF)
Memory TypeMemory Size
(Bytes)
Time of Day AlarmsFunctionsPackage/PinsBudgetary
Price
typSee Notes
DS1388I2C3
3.3
5
4106EEPROM5120RTC
Watchdog Timekeeper
SOIC(N)/8$2.08 @1k
Quality and Environmental Data
Ordering Information
Part NumberStatusRecommended ReplacementPackageTempRoHS
DS1388Z-3No Longer AvailableDS1388Z-3+SOIC(N),;8 pin;30.9 mm²-40°C to +85°CNo
DS1388Z-3+ActiveSOIC(N),;8 pin;30.9 mm²-40°C to +85°CLead Free
DS1388Z-3+T&RActiveSOIC(N),;8 pin;30.9 mm²-40°C to +85°CLead Free
DS1388Z-33No Longer AvailableDS1388Z-33+SOIC(N),;8 pin;30.9 mm²-40°C to +85°CNo
DS1388Z-33+ActiveSOIC(N),;8 pin;30.9 mm²-40°C to +85°CLead Free
DS1388Z-33+T&RActiveSOIC(N),;8 pin;30.9 mm²-40°C to +85°CLead Free
DS1388Z-5No Longer AvailableDS1388Z-5+SOIC(N),;8 pin;30.9 mm²-40°C to +85°CNo
DS1388Z-5+ActiveSOIC(N),;8 pin;30.9 mm²-40°C to +85°CLead Free
DS1388.pdf DS1388
DS1388.pdf DS1388
DS1388.pdf DS1388
Tips for Writing Bulletproof Real-Time Clock Control Code DS3234
State Machine Logic in Binary-Coded Decimal (BCD)-Formatted Real-Time Clocks DS3234
Oscillator Design Considerations for Low-Current Applications DS17885
Using the Dallas Tricklecharge Timekeeper DS1672
Crystal Considerations with Maxim Real-Time Clocks (RTCs) DS3234
DS1388.pdf DS1388
DS1388.pdf DS1388