SM8577B
NIPPON PRECISION CIRCUITS INC.
Real-time Clock IC
OVERVIEW
The SM8577B is a CMOS serial-interface type real-
time clock IC that operates at 32.768 kHz. It
employs a 3-line serial interface to transfer time and
date data. It incorporates a supply-voltage detect
function to determine data validity/invalidity. It
features an output interrupt with 32 kHz or 1 Hz
output frequency. It is available in 8-pin SOPs.
PINOUT
CE
DATA
CLK
FOUT
1
8
VDD
XTN
XT
VSS
8577B
FEATURES
s
s
s
s
s
4
5
s
s
s
s
s
2.5 to 5.5 V operating voltage range
1.0 µA at 3.0 V (typ) current consumption
3-line serial interface
1.7 ± 0.3 V supply voltage detection threshold
Timer counters for second, minute, hour, day, day
of the week, month, and year
Automatic leap-year calendar adjustment
32.768 kHz and 1 Hz output interrupt selectable
Crystal oscillator circuit built-in (C
D
built-in)
24-hour time mode
8-pin SOP
PACKAGE DIMENSIONS
Unit: mm
8-pin SOP
0.15
−
0.05
+
0.10
4.4 0.2
6.2 0.3
5.2 0.3
0 to 10∞
ORDERING INFOMATION
Device
SM8577BS
Package
8pin SOP
0.4 0.1
NIPPON PRECISION CIRCUITS—1
0.05 0.05
1.5 0.1
1.27
4.4 0.2
NPC [ NIPPON PRECISION CIRCUITS INC ]
