SM8577B Datasheet, PDF (2/10 Pages) Nippon Precision Circuits Inc – Real-time Clock IC

BLOCK DIAGRAM
XT
XTN
SM8577B
VDD
VSS
OSC
Divider
Timer Counter
FOUT
DATA
CLK
CE
Output
Controller
I/O
Controller
Voltage
Detect
Shift Register
Controll
Circuit
PIN DESCRIPTION
Number
Name
1
CE
2
DATA
3
CLK
4
FOUT
5
VSS
6
XT
7
XTN
8
VDD
I/O
Description
Chip enable. With pull-down resistor built-in.
I
HIGH: Enable
LOW: DATA goes high impedance; input on CLK and DATA stops; and the TM bit is cleared.
I/O
Data read and write input/output
I
Serial clock input.
Data is input (write mode) and output (read mode) on the rising edge of CLK.
Frequency output (controlled by the 4th data bit of the ‘week’ data, FSEL).
O
1 Hz output when FSEL is 0, and 32.768 kHz output when FSEL is 1.
In 1 Hz output mode, the 1 Hz signal is synchronized to the internal 1 second signal.
FOUT output is not affected by the CE signal.
–
Ground
I
Crystal oscillator element connection pin
O
Crystal oscillator element connection pin. Oscillator capacitor C_D is built-in.
–
Supply voltage.
Connect a ≥ 0.1 µF capacitor between VDD and VSS.
NIPPON PRECISION CIRCUITS—2