Top

SPI-Compatible RTC with Microprocessor Supervisor, Alarm, and NV RAM Controller

Product Details

Key Features

Simplified Block Diagram

Technical Docs

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .

Key Features

  • Real-Time Clock Counts
    Seconds, Minutes, Hours, Date, Month, Day of
    Week, and Year with Leap-Year Compensation
    Through 2099
  • 4MHz SPI-Bus-Compatible Interface at 5V, 2MHz at 3V, and 3.3V
  • SPI Interface Supports Modes 1 and 3 (0, 1 and 1, 1)
  • 96 x 8 Bits of RAM for Scratchpad Data Storage
  • Uses Standard 32.768kHz, 6pF Load, Watch Crystal
  • Single-Byte or Multiple-Byte (Burst Mode) Data Transfer for Read or Write of Clock Registers or RAM
  • Battery Monitor and Low-Battery Warning Output
  • Internal Default for Lithium Backup-Battery Testing
    Pins Available for Other Backup-Battery
    Testing Configurations
  • Dual Power-Supply Pins for Primary and Backup Power
  • Battery-On Output
  • NV RAM Controller
  • Chip-Enable Gating (Control of CE-bar with Reset
    and Power Valid)
    VOUT for SRAM Power
  • µP Supervisor with Watchdog Input
  • Programmable Time/Date Alarm Output
  • Data Valid Bit (Loss of All Voltage Alerts User of Corrupt Data)
  • Crystal-Fail Detect
  • Small 20-Pin, QSOP Surface-Mount Package
  • Applications/Uses

    • Digital Thermostats
    • Fax Machines
    • Industrial Control
    • Intelligent Instruments
    • Point-of-Sale Equipment
    • Programmable Logic Controller

    Description

    The MAX6916 provides all the features of a real-time clock (RTC) plus a microprocessor supervisory circuit, NV RAM controller, and backup-battery monitor function. In addition, 96 x 8 bits of static RAM are available for scratchpad storage. The MAX6916 communicates with a microprocessor through an SPI™-bus-compatible serial interface.

    The real-time 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 years through 2099. The clock operates in either 24hr or 12hr format with an AM/PM indicator. A time/date-programmable alarm function is provided with an open-drain, active-low alarm output.

    The microprocessor supervisory circuit features an open-drain, active-low reset available in three different reset thresholds. A manual reset input and a watchdog function are included as well.

    The NV RAM controller provides power for external SRAM from a backup battery plus chip-enable gating. The backup battery also provides data retention of the on-board 96 x 8 bits of RAM. An open-drain, active-low, battery-on signal alerts the system when operating from a battery.

    The battery-test circuitry periodically tests the backup battery for a low-battery condition. An optional external resistor network selects different battery thresholds. A freshness seal prevents battery drain until the first VCC power-up.

    The MAX6916 has a crystal-fail-detect circuit and a data-valid bit. The MAX6916 is available in a 20-pin QSOP package and is guaranteed to operate over the extended temperature range from -40°C to +85°C.

    Simplified Block Diagram

    Technical Docs

    Support & Training

    Search our knowledge base for answers to your technical questions.

    Filtered Search

    Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .