Lo w -Fre q u e n c y Du a l Ec o n Os c illa t o r
Fu n c t io n a l Dia g ra m
V
CC
MASTER
OSCILLATOR
1.048MHz
V
CC
DS1099
GND
f
MOSC
DIVIDER 0
DIVIDE BY 2
X
f
OUT0
OUTPUT
DRIVER
OUT0
OUT1
(X = X = 0...22)
0
FACTORY-
PROGRAMMED
EEPROM
DIVIDER 1
DIVIDE BY 2
X
f
OUTPUT OUT1
DRIVER
(X = X = 0...22)
1
OE0
OE1
pendently enabled/disabled using the output-enable
pins, OE0 and OE1, respectively. When the output-
enable pins are active (low), the corresponding outputs
are enabled. If either output-enable pin is tied to its
inactive state (high), then the corresponding output is
disabled and forced high immediately. The output-
e na ble pins only disa ble the c orre sponding output
driver(s) and do not shut down the master oscillator or
the dividers.
De t a ile d De s c rip t io n
The DS1099 consists of a fixed-frequency 1.048MHz
master oscillator followed by two independent factory-
programmable dividers. The two divider outputs are
connected to pins OUT0 and OUT1, which are inde-
Table 1. Divider Settings and Output
Frequencies
Since the master oscillator frequency, f
the frequency of OUT0 and OUT1 is determined by
DIVIDER 0 and DIVIDER 1, respectively. And since
, is fixed,
MOSC
DIVIDER SETTING
DIVISOR
f
OR f
OUT0 OUT1
X OR X
0
1
0
1
1
1.048MHz
0.524MHz
0.262MHz
0.131MHz
65.50kHz
32.75kHz
—
each output has its own divider, f
and f
can
OUT0
OUT1
2
be programmed independent of each other.
2
4
8
The frequency of the outputs are calculated as follows:
3
X
X
X
0
X
1
0
/ 2 = 1.048MHz / 2
f
= f
= f
OUT0
MOSC
1
/ 2 = 1.048MHz / 2
MOSC
4
16
f
OUT1
5
32
whe re X is the DIVIDER 0 s e tting a nd X is the
0
1
DIVIDER 1 setting. Valid values for X and X are inte-
0
1
—
19
20
21
22
—
gers 0 to 22 (dec).
524,288
1,048,576
2,097,152
4,194,304
2Hz
Table 1 shows output frequencies and divider values
for the range of divider settings.
1Hz
0.5Hz
0.25Hz
_____________________________________________________________________
5