CF5762AB0 Datasheet, PDF (8/10 Pages) Nippon Precision Circuits Inc – Analog Chime Clock CMOS IC

CF5762AB0
Melody Stop at Night
The melody output can be disabled at night by the
state of AMI and PMI. This function disables the
melody output from 11:00PM to 5:45AM, inclusive.
AMI and PMI have built-in pull-down resistors.
Melody Stop when Dark
When a CdS element and resistor is connected
between CO4N and VDD with the mid-point poten-
tial connected to CDS, the CDS input can be used to
detect the brightness and to stop melody output when
the surroundings become dark.
CDS
LOW
HIGH
Melody output
Disabled due to darkness
Enabled
The CDS input has a built-in pull-up resistor when
inactive. This pull-up is switched off when CO4N
output is LOW. CO4N goes LOW in response to the
hourly signal input on MT signal. The melody play
output is then disable/enabled depending on the state
of the CDS input.
If this function is not used, the CDS input must be
tied HIGH.
Note that when used together with the melody stop at
night function, melody output can be disabled by
either function.
AMI
PMI
Melody output
LOW LOW Always enabled
LOW HIGH Disabled during PM hours (PM flag is HIGH)
HIGH LOW Disabled during AM hours (PM flag is LOW)
HIGH HIGH Always disabled
Note that when used together with the melody stop
when dark function, melody output can be disabled
by either function.
VDD
CdS element
CDS
CO4N
Figure 3. Darkness detection circuit
MT etc
CO4N
Read clock
(on rising edge)
11.719ms
15.625ms
Pull-up Open Pull-down
CDS
HIGH:play mode (light)
LOW:non-play mode (dark)
Figure 4. Darkness detection timing
Melody Play Mode
The melody output plays in complete one-shot mode
only.
A complete one-shot melody plays through to the
end of a whole melody and does not start again as
long as the current melody play conditions do not
change, even if the hourly signal is input again.
However, if during melody play the melody output
stops or other melody start conditions change, the
current melody output may stop.
NIPPON PRECISION CIRCUITS INC.—8