SHANGHAI
BELLING
BL5373
Low Power Real-Time Clock (RTC)
GENERAL DESCRIPTION
The BL5373 is a CMOS type real-time clock,
which is connected to the CPU via two wires
and capable of serial transmission of clock to
the CPU. The BL5373 can generate various
periodic interrupt clock pulses lasting for long
period (one month), and alarm interrupt can be
made by two incorporated systems. Since an
oscillation circuit is driven at a constant
voltage, it undergoes fluctuations of few
voltage and consequently offers low current
consumption (TYP. 400nA @ 5V)
It also provides an oscillator halt sensing
function applicable for data validation at
power-on and other occasions. The product
also incorporates a time trimming circuit that
adjusts the clock with higher precision by
adjusting any errors in crystal oscillator
frequencies based on signals from the CPU.
The crystal oscillator may be selected from
32KHz or 32.768KHz types.
It adopts 8-pin SOP or TSSOP package.
FEATURES
Lowest supply current: 400nA TYP. @ 5V
Connected to the CPU via only 2-wires
(MAX. 100KHz)
A clock counter (counting hours, minutes,
and seconds) and a calendar counter
(counting leap years, years, months, days,
and days of the week) in BCD codes
Two systems output providing interrupt to
the CPU output (period of one month to one
second, interrupt halt function)
Two systems output of alarm functions
Oscillation halt sensing to judge internal
data validity
Clock output of 32.768KHz (32KHz)
(output controllable via a register)
Second digit adjustment by
±30
seconds
Automatic leap year recognition up to the
year 2099
12-hour or 24-hour time display selectable
High precision time trimming circuit
Oscillator of 32.768KHz or 32KHz may be
used
CMOS logic
Package: 8pin SOP or TSSOP
BL5373 Data Sheet
1
BELLING [ SHANGHAI BELLING CO., LTD. ]
