DC814 QUICK START QUIDE
5
NOTE:
The typical VCO control voltage range depends on the clock
IC, the ratio of the R SET and R IN resistors and the V+ voltage.
VCO operation is not guaranteed if the VCO voltage forces the
clock’s frequency outside the frequency range show n on Table 3.
Refer to the LTC6905 data sheet for a VCO design guide or to a
M ay 2002 Linear Technology M agazine article: How to use the
LTC6900 as a VCO.
V+=3V
V+=5V
LTC6905
0V - 1.6V
1.2V – 3.6V
100.5M Hz –168.5M Hz 70M Hz – 168.5M Hz
R SET = 9.09k and R IN = 40.2k
LTC1799
0V – 3V
0V – 3.7V
18.5M Hz – 33M Hz
9M Hz – 33M Hz
R SET = 3.01k and R IN = 14.7k
LTC6900
0V – 1.7V
0V – 3.7V
12M Hz – 20M Hz
5M Hz – 20M Hz
R SET = 9.09k and R IN = 40.2k
TABLE 3. Frequency Range and Accuracy of Clock ICs
RSET= (RSET1+ RSET2) on the Buffer Board and
RSET= RS1 on the DIP-8 Clock Board.
LTC6905
(Board Version –A)
RSET = 3370/(2·Fosc·N-3),
(
Fosc in M Hz and R SET in kΩ )
N = 1, 69M Hz≤ fosc≤170M Hz (JP2 1-2)
N = 2, 34M Hz≤fosc≤85M Hz (JP2 3-4)
N = 4, 17M Hz≤fosc≤42M Hz (JP2 5-6)
M aximum Frequency Error at 25
°C
:
±1.4% at V+=2.7V to 3.6V and ±2.2% at V+=5V
LTC1799
(Board Version –B)
RSET = 100/(Fosc·N)
, (
Fosc in M Hz and R SET in kΩ )
N = 1, 0.1M Hzfosc≤33M Hz (JP2 5-6)
N=10, 10kH ≤fos≤3.3M Hz
(JP2 3-4)
N = 100, 1kHz≤ fosc≤330kHz (JP2 1-2)
M aximum Frequency Error at 25
°C
:
±1.5% at V+=3V and ±1.5% at V+=5V
LTC6900
(Board Version –C)
RSET = 200/(Fosc·N),
(
Fosc in M Hz and R SET in kΩ )
N = 1, 0.1M Hz≤fosc≤20M Hz (JP2 5-6)
N = 10, 10kHz≤fosc≤2M Hz (JP2 3-4)
N = 100, 1kHz≤fosc≤200kHz (JP2 1-2)
M aximum Frequency Error at 25
°C
:
±1.5% at V+=3V and ±1.5% at V+=5V
LTC6905-133
(Board Version –D )
N = 1, 133M Hz; N = 2, 66.7M Hz; N = 4, 33.5M Hz
M aximum Frequency Error at 25 °C: ±1.0% at V+=2.7V to 3.6V
and ±1.5% typical at V+=5V
LTC6905-100
(Board Version –E)
N = 1, 100M Hz; N = 2, 50M Hz; N = 4, 25M Hz
M aximum Frequency Error at 25 °C: ±1.0% at V+=2.7V to 3.6V
and ±1.5% typical at V+=5V
LTC6905-96
(Board Version –F)
N = 1, 96M Hz; N = 2, 48M Hz; N = 4, 24M Hz
M aximum Frequency Error at 25 °C: ±1.0% at V+=2.7V to 3.6V
and ±1.5% typical at V+=5V
LTC6905-80
(Board Version –G)
N = 1, 80M Hz, N = 2, 40M Hz; N = 4, 20M Hz
M aximum Frequency Error at 25 °C: ±1.0% at V+=2.7V to 3.6V
and ±1.5% typical at V+=5V
LTC6906
(Board Version –H)
RSET = 100/(Fosc·N),
(
Fosc in M Hz and R SET in kΩ )
N = 1, 0.1M Hz≤fosc≤ 1M Hz (JP2 5-6)
N = 3, 33kHz≤fosc≤333kHz (JP2 3-4)
N = 10, 10kHz≤fosc ≤100kHz (JP2 1-2)
M aximum Frequency Error at 25
°C
: ±0.5% at V+=2.7V to 3.6V
LTC6907
(Board Version –
I
)
RSET = 200/(Fosc·N),
(
Fosc in M Hz and R SET in kΩ )
N = 1, 0.4M Hz≤fosc≤4M H (JP2 5-6)
N = 3, 133M Hz≤fosc≤1.33M Hz (JP2 3-4)
FIGURE 5. VCO Circuit of Buffer Board
Summary of Contents for DC814
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