CBC921xx Power Management (PM) Realtime Clock/Calendar (RTC)

Cymbet's RTCs feature battery-charge and power management capabilities for applications such as power bridging

Image of Cymbet's CBC921xx PMRTCCymbet's CBC921xx combines an RTC, a backup battery charger, and other power management features. In the event of a primary power source outage, automatic switchover to the backup battery enables extended timekeeping and provides the option to power external devices so they maintain operation during the power outage. The circuit can provide an uninterrupted continuous-time clock/calendar with time-based interrupts or alarms for waking up from sleep to active-mode operation with adjustable intervals to save power in the overall system.

In normal operation, the RTC function is supported by a primary power source which can be a single battery cell, multiple alkaline cells, or a regulated power supply ranging from 2.85 V to 5.5 V. A backup battery that might be used is charged with a temperature-compensated voltage derived from the primary voltage source. Backup battery charging is done on a configurable schedule and temperature-dependent duty-cycle which are designed to increase the service life of the backup battery while minimizing power consumption from the main power source.

The PM has a low quiescent current and high efficiency for backup battery charging. The RTC circuit has an ultra-low quiescent current and accuracy of ±1 ppm. An open-drain internal power switch is controlled by interrupts and a sleep manager to facilitate power-saving by disconnecting the main power from external devices according to user-defined schedules. The CBC921xx devices feature an on-chip temperature sensor with a 10-bit ADC and VOUT pin to power external devices during backup-mode.

Features
  • Ultra-low-power RTC:
    • 50 nA with a crystal oscillator
    • 20 na with an RC oscillator
  • Integrated low-side (VSS) power switch
  • On-chip temperature sensor with a 10-bit ADC
  • I2C- and SPI-bus options
  • Battery charger and cutoff circuit:
    • 4.1 V for EnerChips and Li-Ion
    • 3.2 V option for coin cells and supercapacitors
  • Programmable charger with automatic shutoff minimizes power consumption
  • Full clock/calendar, alarm, and interrupt functions
Applications
  • Power bridging to provide uninterruptible RTC function during the exchange of main batteries
  • Consumer appliances with RTCs; provides switchover power from the main supply to the backup battery
  • Ultra-low-power timers using 20 nA
  • Wireless sensors, RFID tags, and other powered, low duty-cycle applications
  • Business and industrial systems: network routers, point-of-sale (POS) terminals, single-board computers, test equipment, multi-function printers, industrial controllers, and utility meters:
    • Reliable system timekeeping
    • Battery-powered devices
    • Internet of Things (IoT) and portable devices
    • Daily alarms

CBC921xx PMRTCs

ImageManufacturer Part NumberDescriptionAvailable QuantityView Details
POWER MANAGER / RTC 3.2V VBATCBC92132C-Q3-TR3POWER MANAGER / RTC 3.2V VBAT5359 - ImmediateView Details
POWER MANAGER / RTC 4.1V VBATCBC92141C-Q3-TR3POWER MANAGER / RTC 4.1V VBAT3929 - ImmediateView Details

Evaluation Kits

ImageManufacturer Part NumberDescriptionAvailable QuantityView Details
ENERCHIP PMRTC EVAL KIT 4.1V CHGCBC-EVAL-14-PMRTC-41ENERCHIP PMRTC EVAL KIT 4.1V CHG3 - ImmediateView Details
ENERCHIP PMRTC EVAL KIT 3.2V CHGCBC-EVAL-14-PMRTC-32ENERCHIP PMRTC EVAL KIT 3.2V CHG3 - ImmediateView Details
Published: 2019-09-17