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Real Time Clock (RTC) IC Clock/Calendar 56B I2C, 2-Wire Serial 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)

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DS1308U-18+T General Description

The DS1308 serial real-time clock (RTC) is a low-power, full binary-coded decimal (BCD) clock/calendar plus 56 bytes of NV RAM. Address and data are transferred serially through an I²C interface. The clock/calendar provides seconds, minutes, hours, day, date, month, and year information. The end of the month date 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. The DS1308 has a built-in power-sense circuit that detects power failures and automatically switches to the backup supply, maintaining time and date operation.

Analog Devices, Inc Inventory

Key Features

  • Compatible with Crystal ESR Up to 100kΩ Allows a Crystal to be Optimized for Cost and Space
  • Low-Power Operation Extends Battery Backup Run Time
    • Low Timekeeping Current of 250nA (typ)
    • Automatic Power-Fail Detect and Switch Circuitry
  • Completely Manages All Timekeeping Functions
    • Real-Time Clock Counts Seconds, Minutes, Hours,Date of the Month, Month, Day of the Week, andYear with Leap-Year Compensation Valid Up to 2400
    • External Clock Source for Synchronization ClockReference (e.g., 32kHz, 50Hz/60Hz Powerline,GPS 1PPS)
    • 56-Byte, Battery-Backed, General-Purpose RAM with Unlimited Writes
    • Programmable Square-Wave Output Signal
  • Simple Serial Port Interfaces with Most Microcontrollers
    • I2C Serial Interface
  • Industrial Temperature Range: -40°C to +85°C Supports Operation in a Wide Range of Applications
  • Underwriters Laboratories (UL®) Recognized
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  • Consumer Electronics (Set-Top Box, Digital Recording, Network Appliance)
  • Handhelds (GPS, POS Terminal)
  • Medical (Glucometer, Medicine Dispenser)
  • Office Equipment (Fax/Printer, Copier)
  • Other (Utility Meter, Vending Machine, Thermostat, Modem)
  • Telecommunications (Router, Switcher, Server)
Analog Devices, Inc Inventory


model DS1308U-18+T package Micro-MAX, Thin Shrink Small-Outline
packingQty Reel,3000 packingOption Reel
packageType U8+1 rohs roHSY
lifeCycle production tempRange -40 to 85C
Manufacturer Analog Devices Inc. Product Category Real Time Clock
RoHS Details Mounting Style SMD/SMT
Package / Case uSOP-8 RTC Bus Interface Serial, 2-Wire, I2C
Date Format YY-MM-DD-dd Time Format HH:MM:SS (12 hr, 24 hr)
Battery Backup Switching Backup Switching RTC Memory Size 56 B
Supply Voltage - Max 5.5 V Supply Voltage - Min 1.71 V
Minimum Operating Temperature - 40 C Maximum Operating Temperature + 85 C
Brand Analog Devices / Maxim Integrated Product Type Real Time Clocks
Series DS1308U Factory Pack Quantity 3000
Subcategory Clock & Timer ICs Part # Aliases DS1308U 90-1308U+18T
DS1308: Typical Operating Circuit

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