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DS12R885：RTCs with Constant-Voltage Trickle Charger

The DS12R885 is a functional drop-in replacement for the DS12885 real-time clock (RTC). The device provides an RTC/calendar, one time-of-day alarm, three maskable interrupts with a common interrupt output, a programmable square wave, and 114 bytes of battery-backed static RAM. The date at the end of the month is automatically adjusted for months with fewer than 31 days, including correction for leap years. It also operates in either 24-hour or 12-hour format with an AM/PM indicator. A precision temperature-compensated circuit monitors the status of VCC. If a primary power failure is detected, the device automatically switches to a backup supply. The VBACKUP pin supports a rechargeable battery or a super cap and includes an integrated, always enabled trickle charger. The DS12R885 is accessed through a multiplexed byte-wide interface, which supports both Intel and Motorola modes. The DS12CR887 and DS12R887 integrate the DS12R885 die with a crystal and battery.

Key Features Trickle-Charge Capability for a Rechargeable Battery or Super Cap Selectable Intel or Motorola Bus Timing RTC Counts Seconds, Minutes, Hours, Day, Date, Month, and Year with Leap-Year Compensation to 2100 Interrupt Output with Three Independently Maskable Interrupt Flags Time-of-Day Alarm is Once-per-Second to Once-per-Day Periodic Rates from 122µs to 500ms End-of-Clock Update Cycle Flag 14 Bytes of Clock and Control Registers 114 Bytes of General-Purpose Battery-Backed NV RAM with Clear Input Programmable Square-Wave Output Automatic Power-Fail Detect and Switch Circuitry +5.0V or +3.3V Operation Industrial Temperature Range DS12CR887 Encapsulated DIP (EDIP) Module with Integrated Battery and Crystal DS12R887 BGA Module Surface-Mountable Package with Integrated Crystal and Rechargeable Battery

DS12CR887, DS12R885, DS12R887: Typical Operating Circuit Applications/Uses Embedded Systems Network Hubs, Switches, Routers Security Systems Utility Meters

DataSheet

Parametrics

Quality and Environmental Data

• DS12R885.pdf

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