Part Number: AB0805-T3

Manufacturer: Abracon LLC


Shipped from: Shenzhen/HK Warehouse

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Technical Specifications of AB0805-T3

Category Integrated Circuits (ICs)
Family Clock/Timing – Real Time Clocks
Manufacturer Abracon LLC
Packaging Tape & Reel (TR)
Part Status Active
Type Clock/Calendar
Features Alarm, Leap Year, SRAM, Trickle-Charger, Watchdog Timer
Memory Size 256B
Time Format HH:MM:SS:hh
Date Format YY-MM-DD-dd
Interface I2C, 2-Wire Serial
Voltage – Supply 1.7 V ~ 3.6 V
Voltage – Supply, Battery 1.5 V ~ 3.6 V
Current – Timekeeping (Max) 0.17μA ~ 0.22μA @ 1.8V ~ 3V
Operating Temperature -40°C ~ 85°C
Mounting Type Surface Mount
Package / Case 16-VFQFN Exposed Pad
Supplier Device Package 16-QFN (3×3)

AB0805-T3 Description

The Real Time Clock AB0805-T3 breaks new ground by combining an extremely low power consumption with a rich and flexible set of features. These are the first semiconductor products built on Abracon Corporation’s cutting-edge SPOT (Subthreshold Power Optimized Technology by Ambiq Micro) CMOS platform, allowing extremely low power consumption (as low as 15nA) compared to other RTCs in the industry.

With its on-chip oscillators, low power consumption, programmable counters and alarms for timer and watchdog functions, and an I2C or SPI serial interface for communication with a host controller, the AB08XX is an ideal choice for low-power applications. Microcontrollers and other host processors provide a complete real-time clock. Thanks to its integrated power management features, the AB08XX can function as a backup unit in both mains-powered and battery-operated setups.

AB0805-T3 Features

  • Ambiq Micro’s optimized technology for sub-threshold power consumption.
  • The minimal current input is required.
  • 32kHz Compact crystal oscillator with built-in load components.
  • There are counters for tenths of a second, minutes, and hours, as well as the current date, month, year, century, and weekday.
  • There is an alarm system for each counter.
  • It can generate clock signals at the output with a frequency range of 32kHz to 1/year.
  • The timer counts down and can be set to repeat.
  • Calculation of the leap year is performed automatically.
  • Low-power RC oscillator built right in.
  • Precision crystal adjustment to 2ppm.
  • 16ppm precision RC accuracy calibration.
  • The RC oscillator is automatically calibrated to the crystal oscillator.
  • Resettable hardware watchdog timer.
  • There can be as much as 256 bytes of RAM available in any application.
  • Transitioning to VBAT instantly.
  • Outside interrupt logger.
  • Detection of brownouts can be programmed.
  • Digital-to-analog converter with a programmable voltage comparator

Functional Description

Battery Backed Up RTC

The most typical use for an AB08X5 is a real-time clock (RTC) with backup battery power and optional RAM storage. The AB08X5 typically draws power from a larger battery that is part of the system’s power supply. The AB08X5’s built-in trickle charger charges a supercapacitor or rechargeable battery. The AB08X5 will switch over to the VBAT supply and keep the time and RAM data at shallow battery supply currents if the main power supply is lost.

The AB08X5 is a complete real-time clock solution for host processors like microcontrollers (RTC).  The AB08X5 has three feature groups: 1) essential timekeeping functions, 2) advanced timekeeping features, and 3) basic power management features. Through the use of I/O offset-mapped registers, it is possible to exercise control over the functions associated with each feature group.

A serial interface that uses the I2C protocol (like the one found in the AB0805), or a serial interface that uses the SPI protocol, can be used to access these registers (e.g., in the AB0815). Following a brief explanation of each feature group is an expanded discussion of that group’s components explained in succeeding sections. The default timekeeping feature set allows for crystal (XT) oscillation at 32.786 kHz. This mode provides the highest possible frequency accuracy while using an ultra-low current of only 55 nA. A common set of counters measuring hundredths of a second up through centuries is also included in the feature group for the baseline timekeeping capability. Additionally, a complement of countdown timers and alarms can be configured to trigger interruptions or resets on several of the outputs. This can be done in a variety of ways.

The sophisticated timekeeping feature group supports RC oscillator and autocalibration oscillation modes. For applications that only need moderate frequency accuracy, the temperature-compensated RC oscillator mode can be used instead of the XT oscillator, resulting in an even lower current drain. This mode draws only 14 nA of current. The AB08X5 is equipped with a patented calibration algorithm that enables it to digitally tune the frequency of the RC oscillator and the XT oscillator to an accuracy of as little as 2 parts per million (ppm) at a given temperature. The RC oscillator is the primary oscillation source when the Autocalibration mode is active and periodically calibrated against the XT oscillator. The autocalibration process could be set to run every 8.5 minutes or 17 minutes on its own, or it could be started manually through the software. This mode makes it possible to draw an average current of only 22 nA while maintaining frequency accuracy comparable to that of the XT oscillator.

The watchdog timer functionality, the generation of clock outputs, and the monitoring of external interrupts are all made possible by the rich input and output configuration options included in the advanced timekeeping feature group. These options can be found in the progressive timekeeping feature group. The AB08X5 can function as a backup device in both line-powered and battery-powered systems thanks to the power management mechanisms incorporated into it. When the main power supply (VCC) falls below a certain threshold, an inbuilt power control module will immediately switch to the backup power supply (VBAT). When running off backup power, 256 bytes of RAM with extremely low leakage allow for storing essential parameters. On the backup power supply, the AB08X5 additionally features digitally-tunable voltage sensing for added convenience.

Battery Backed Up RTC

The most typical use for an AB08X5 chip is in a real-time clock (RTC) powered by a battery and storing data in RAM if necessary. The AB08X5 receives its power, in most cases, from a system power supply, which may take the form of a bigger battery. Whether it’s a supercapacitor or a rechargeable battery, the AB08X5’s built-in trickle charger is steadily topping off the charge on either. The AB08X5 will automatically switch to the VBAT supply if the primary power supply fails. This allows the device to keep the time and RAM data while operating at shallow battery supply currents.


In most cases, an AB08X5 chip will be found in a battery-operated real-time clock (RTC) with RAM for temporary data storage. Typically, the AB08X5 is powered by a larger battery or another source integrated into the system. The built-in trickle charger of the AB08X5 is slowly topping off the charge of a supercapacitor or rechargeable battery. If the primary power source fails, the AB08X5 will automatically switch over to the VBAT supply. Due to this, the gadget may continue storing time and RAM data while drawing extremely little power from the battery.

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