LTC1164-7CS View Datasheet(PDF) - Linear Technology
Part Name
Description
MFG CO.
'LTC1164-7CS' PDF : 12 Pages View PDF
LTC1164-7
APPLICATI S I FOR ATIO
Transient Response
INPUT = 1kHz ± 3V
fCLK = 500kHz
fC = 10kHz
VS = ±7.5V
100µs/DIV
Figure 5
ts
INPUT
90%
50%
td
1164-7 F05
OUTPUT
If, for instance, an LTC1164-7 operating with a 100kHz
clock and 1kHz cutoff frequency receives a 98kHz 10mV
input signal, a 2kHz, 143µVRMS alias signal will appear at
its output. When the LTC1164-7 operates with a clock-to-
cutoff frequency of 50:1, aliasing occurs at twice the clock
frequency. Table 11 shows details.
Table 11. Aliasing (fCLK = 100kHz)
INPUT FREQUENCY
(VIN = 1VRMS,
fIN = fCLK ± fOUT)
(kHz)
50:1, fCUTOFF = 2kHz
190 (or 210)
195 (or 205)
196 (or 204)
197(or 203)
198 (or 202)
199.5 (or 200.5)
100:1, fCUTOFF = 1kHz
97 (or 103)
97.5 (or 102.5)
98 (or 102)
98.5 (or 101.5)
99 (or 101)
99.5 (or 100.5)
OUTPUT LEVEL
(Relative to Input,
0dB = 1VRMS)
(dB)
– 76.1
– 51.9
– 36.3
– 18.4
– 3.0
– 0.2
– 74.2
– 53.2
– 36.9
– 19.6
– 5.2
– 0.7
OUTPUT FREQUENCY
(Aliased Frequency
fOUT = ABS [fCLK ± fIN])
(kHz)
10.0
5.0
4.0
3.0
2.0
0.5
3.0
2.5
2.0
1.5
1.0
0.5
10%
tr
RISE
TIME
(tr)
=
0.39
fCUTOFF
±
5%
SETTLING
(TO 1% of
TIME (ts)
OUTPUT)
=
2.2
fCUTOFF
±5%
TIME DELAY (td) = GROUP
(TO 50% OF OUTPUT)
DELAY
≈
1.2
fCUTOFF
1164-7 F06
Figure 6
Aliasing
Aliasing is an inherent phenomenon of sampled data
systems and it occurs when input frequencies close to the
sampling frequency are applied. For the LTC1164-7 case
at 100:1, an input signal whose frequency is in the range
of fCLK ±3%, will be aliased back into the filter’s passband.
VS = ±7.5V
fCLK = 1MHz
fC = 20kHz
(fCLK/fC) = 50:1
5µs/DIV
Figure 7. Eye Diagram
1164-7 F07
11647fb
12
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