11

LTC1064-7

S

APPLICATI

I FOR ATIO

Speed Limitations

To avoid op amp slew rate limiting at maximum clock

frequencies, the signal amplitude should be kept below a

specified level as shown in Table 9.

POWER SUPPLY

±7.5V

5.0MHz

4.5MHz

4.0MHz

≥ 3.5MHz

±5V

3.5MHz

≥ 3.0MHz

Single 5V

2.0MHz

Table 10. Transient Response of LTC Lowpass Filters

DELAY

RISE

SETTLING

OVER-

TIME*

TIME**

TIME***

SHOOT

LOWPASS FILTER

(SEC)

(SEC)

(SEC)

(%)

LTC1064-3 Bessel

0.5

LTC1164-5 Bessel

0

LTC1164-6 Bessel

1

LTC1264-7 Linear Phase

5

LTC1164-7 Linear Phase

5

LTC1064-7 Linear Phase

5

LTC1164-5 Butterworth

11

LTC1164-6 Elliptic

18

LTC1064-4 Elliptic

20

LTC1064-1 Elliptic

20

* To 50%

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

INPUT FREQUENCY

OUTPUT LEVEL

OUTPUT FREQUENCY

(Relative to Input,

(Aliased Frequency

(kHz)

(dB)

(kHz)

190 (or 210)

–76.1

10.0

195 (or 205)

– 51.9

5.0

196 (or 204)

– 36.3

4.0

197 (or 203)

– 18.4

3.0

198 (or 202)

– 3.0

2.0

199.5 (or 200.5)

– 0.2

0.5

97 (or 103)

–74.2

3.0

97.5 (or 102.5)

– 53.2

2.5

98 (or 102)

– 36.9

2.0

98.5 (or 101.5)

– 19.6

1.5

99 (or 101)

– 5.2

1.0

99.5 (or 100.5)

– 0.7

0.5

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.

Transient Response

50

µs/DIV

1064-7 F05

Figure 6.

INPUT

90%

50%

10%

OUTPUT

tr

td

ts

1064-7 F06

±5%

0.39

±5%

(TO 1% of OUTPUT)

2.2

(TO 50% OF OUTPUT)

1.2

Figure 5.

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 LTC1064-7 case

at 100:1, an input signal whose frequency is in the range

If, for instance, an LTC1064-7 operating with a 100kHz

clock and 1kHz cutoff frequency receives a 98kHz, 10mV

input signal, a 2kHz, 143

its output. When the LTC1064-7 operates with a clock-to-

cutoff frequency of 50:1, aliasing occurs at twice the clock

frequency. Table 11 shows details.