LTC1264-7CS datasheet(11/12 Pages) LINER

11 / 12 page

LTC1264-7

APPLICATI

I FOR ATIO

Information furnished by Linear Technology Corporation is believed to be accurate and reliable.

However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-

tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.

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 LTC1264-7 case

at 50:1, an input signal whose frequency is in the range of

fCLK ±10%, will be aliased back into the filter’s passband.

If, for instance, an LTC1264-7 operating with a 100kHz

clock and 2kHz cutoff frequency receives a 95kHz 10mV

input signal, a 5kHz 56

µVRMS alias signal will appear at its

output. When the LTC1264-7 operates with a clock-to-

cutoff frequency of 25:1, aliasing occurs at twice the clock

frequency. Table 10 shows details.

Table 10. Aliasing (fCLK = 100kHz )

INPUT FREQUENCY

OUTPUT LEVEL

OUTPUT FREQUENCY

(VIN = 1VRMS,

(Relative to Input,

(Aliased Frequency

fIN = fCLK ± fOUT)

0dB = 1VRMS)fOUT = ABS [fCLK ± fIN])

(kHz)

(dB)

(kHz)

25:1, fCUTOFF = 4kHz

175 (or 225)

–76

180 (or 220)

– 69

185 (or 215)

– 62

190 (or 210)

– 43

195 (or 205)

– 7

50:1, fCUTOFF = 2kHz

75 (or 125)

–96

80 (or 120)

– 90

85 (or 115)

– 82

90 (or 110)

– 72

95 (or 105)

– 45

99 (or 101)

Table 9. Maximum VIN vs VS and Clock

POWER SUPPLY

MAXIMUM fCLK

MAXIMUM VIN

±7.5V

5.0MHz

1.6VRMS (fIN ≥ 160kHz)

4.5MHz

2.0VRMS (fIN ≥ 160kHz)

4.0MHz

2.5VRMS (fIN ≥ 160kHz)

≥ 3.5MHz

1.6VRMS (fIN ≥ 500kHz)

±5V

3.0MHz

1.6VRMS (fIN ≥ 100kHz)

≥ 3.0MHz

0.7VRMS (fIN ≥ 500kHz)

Single 5V

2.0MHz

0.5VRMS (fIN ≥ 400kHz)

Transient Response

INPUT = 10kHz

± 3V

fCLK = 2.5MHz

RATIO = 25:1

INPUT

90%

50%

10%

OUTPUT

1164-7 F06

RISE TIME (tr) =

±5%

0.36

fCUTOFF

SETTLING TIME (ts) =

±5%

(TO 1% of OUTPUT)

fCUTOFF

TIME DELAY (td) = GROUP DELAY ≈

(TO 50% OF OUTPUT)

1.15

fCUTOFF

Figure 6.

Table 11. Transient Response of LTC Lowpass Filters

DELAY

RISE

SETTLING OVER-

TIME*

TIME**

TIME***

SHOOT

LOWPASS FILTER

(SEC)

(%)

LTC1064-3 Bessel

0.50/fC

0.34/fC

0.80/fC

0.5

LTC1164-5 Bessel

0.43/fC

0.34/fC

0.85/fC

LTC1164-6 Bessel

0.43/fC

0.34/fC

1.15/fC

LTC1264-7 Linear Phase

1.15/fC

0.36/fC

2.05/fC

LTC1164-7 Linear Phase

1.20/fC

0.39/fC

2.20/fC

LTC1064-7 Linear Phase

1.20/fC

0.39/fC

2.20/fC

LTC1164-5 Butterworth

0.80/fC

0.48/fC

2.40/fC

LTC1164-6 Elliptic

0.85/fC

0.54/fC

4.30/fC

LTC1064-4 Elliptic

0.90/fC

0.54/fC

4.50/fC

LTC1064-1 Elliptic

0.85/fC

0.54/fC

6.50/fC

* To 50%

±5%, ** 10% to 90% ±5%, *** To 1% ±0.5%

Figure 5.

µs/DIV

LTC1264-7CS Datasheet(PDF) 11 Page - Linear Technology

LTC1264-7CS Datasheet(HTML) 11 Page - Linear Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12

Datasheet Download

Link URL