AB18X5 Real-Time Clock with Power

Management Family

Date of Issue: October 16, 2014

3.0 x 3.0 mm

Page 6 of 37

Abracon Drawing #453568

Revision: C

3.3 Reset Driven

In another implementation the AB18X5 controls the system MCU using the reset function rather than

switching power. Since many MCUs use much less power when reset, this implementation can save

system power in some cases.

3.4 Battery Backup

In many systems the main power supply is a battery, so the AB18X5 can minimize its current draw by

powering down the MCU and other peripherals. This battery may be replaceable, and a supercapacitor

charged via the AB18X5 trickle charger can maintain system time and key parameters when the main

battery is removed.

VCC

VSS

nRST

RESET

VCC

VSS

AB18X5

MCU

I2C/SPI

PSW/nIRQ2

VCC

VSS

FOUT/nIRQ

IRQ

VCC

VSS

AB18X5

MCU

I2C/SPI

VBAT

Backup

Battery/

Supercap

XO

XI

Main

Battery

1.5k*

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