AB08X5 Real-Time Clock Family

Date of Issue: October 16, 2014

3.0 x 3.0 mm

Page 5 of 33

Abracon Drawing #453567

Revision: C

3. AB08X5 Example Applications

3.1 Battery Backed Up RTC

The most common AB08X5 application is a battery backed up RTC, which maintains time and may hold

data in RAM. The AB08X5 is normally powered from a system power supply, which may be a larger

battery. The AB08X5 is continuously charging a supercapacitor or rechargeable battery via the internal

trickle charger. When the main power supply goes away, the AB08X5 automatically switches to the VBAT

supply and maintains time and RAM data at very low battery supply currents.

3.2 RTC with Interrupt Aggregation

The flexible inputs of the AB08X5 can be used to aggregate a variety of interrupt sources, including

external digital inputs, analog levels, timers and alarms into a single interrupt source to an MCU.

VCC

VSS

FOUT/nIRQ

IRQ

VCC

VSS

AB08X5

MCU

I2C/SPI

VBAT

System Power

Battery/

Supercap

XO

XI

1.5k*

* Total battery series impedance = 1.5k ohms, which may require an external resistor

VCC

VSS

FOUT/nIRQ

IRQ

VCC

VSS

AB08X5

MCU

I2C/SPI

System Power

XO

XI

WDI

EXTI

VBAT

Analog Level

Digital Inputs