AB08X5-RTC Datasheet, PDF (3/33 Pages) Abracon Corporation – Ultra-low supply current

AB08X5 Real-Time Clock Family
Date of Issue: October 16, 2014
3.0 x 3.0 mm
Page 3 of 33
Abracon Drawing #453567
2. Functional Description
Figure 1 illustrates the AB08X5 functional design.
VCC VBAT
Revision: C
nCE
SDI
SCL
SDA/O
XO
XI
WDI
EXTI
I2C/SPI
Interface
Power
Control
Calibration Engine
XT Osc
Divider
RC Osc
Divider
Analog
Compare
100ths
Seconds
Minutes
Hours
Days
Weekdays
Months
Years
Alarms
Timer
WDT
Control
RAM
Int/Clock
FOUT/nIRQ
nIRQ2
nTIRQ
VSS
Figure 1. Detailed Block Diagram
The AB08X5 serves as a full function RTC for host processors such as microcontrollers. The AB08X5
includes 3 distinct feature groups: 1) baseline timekeeping features, 2) advanced timekeeping features,
and 3) basic power management features. Functions from each feature group may be controlled via I/O
offset mapped registers. These registers are accessed using either an I²C serial interface (e.g., in the
AB0805) or a SPI serial interface (e.g., in the AB0815). Each feature group is described briefly below and
in greater detail in subsequent sections.
The baseline timekeeping feature group supports the standard 32.786 kHz crystal (XT) oscillation mode for
maximum frequency accuracy with an ultra-low current draw of 55 nA. The baseline timekeeping feature
group also includes a standard set of counters monitoring hundredths of a second up through centuries. A
complement of countdown timers and alarms may additionally be set to initiate interrupts or resets on
several of the outputs.