LTC1069-1

8

10691fa

APPLICATIONS INFORMATION

Aliasing

Aliasing is an inherent phenomenon of sampled data

systems and it occurs for input frequencies approaching

the sampling frequency. The internal sampling frequency

of the LTC1069-1 is 100 times its cutoff frequency. For

instance, if a 98kHz, 100mVRMS signal is applied at the

input of an LTC1069-1 operating with a 100kHz clock, a

2kHz, 28μVRMS alias signal will appear at the filter output.

Table 4 shows details.

Table 4. Aliasing (fCLK = 100kHz)

INPUT FREQUENCY

(VIN = 1VRMS)

(kHz)

OUTPUT LEVEL

(Relative to Input)

(dB)

OUTPUT FREQUENCY

(Aliased Frequency)

(kHz)

fCLK/fC = 100:1, fCUTOFF = 1kHz

96

(or 104)

97

(or 103)

98

(or 102)

98.5

(or 101.5)

99

(or 101)

99.5

(or 100.5)

–90.0

–86.0

–71.0

–56.0

–1.1

–0.21

4.0

3.0

2.0

1.5

1.0

0.5

TYPICAL APPLICATIONS

Single 3.3V Supply Operation with Output Buffer

Single 5V Operation with Power Shutdown

1

2

3

4

8

7

6

5

VOUT

V–

NC

CLK

AGND

V+

NC

VIN

0.1μF

0.47μF

SHUTDOWN

ON

5V

VIN

VOUT

1069-1 TA04

LTC1069-1

fCLK ≤

750kHz

5V

0V

CMOS LOGIC

1

2

3

4

8

7

6

5

VOUT

V–

NC

CLK

AGND

V+

NC

VIN

0.1μF

0.47μF

VIN

VOUT

10691 TA05

LTC1069-1

fCLK

500kHz

3.3V

0V

–

+

1/2 LT1366

3.3V

0.1μF