LTC1069-7

1

10697fa

TYPICAL APPLICATION

DESCRIPTION

Linear Phase

8th Order Lowpass Filter

The LTC®1069-7 is a monolithic, clock-tunable, linear

phase, 8th order lowpass filter. The amplitude response

of the filter approximates a raised cosine filter with an

alpha of one. The gain at the cutoff frequency is – 3dB and

the attenuation at twice the cutoff frequency is 43dB. The

Single 5V Supply, Linear Phase 100kHz Lowpass Filter

L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.

FEATURES

APPLICATIONS

n 8th Order, Linear Phase Filter in SO-8 Package

n Raised Cosine Amplitude Response

n – 43dB Attenuation at 2× fCUTOFF

n Wideband Noise: 140μVRMS

n Operates from Single 5V Supply to

±5V Power Supplies

n Clock-Tunable to 200kHz with ±5V Supplies

n Clock-Tunable to 120kHz with Single 5V Supply

n Digital Communication Filter

n Antialiasing Filter with Linear Phase

n Smoothing Filters

AGND

V+

NC

VIN

VIN

VOUT

VOUT

V–

NC

CLK

LTC1069-7

fCLK = 2.5MHz

5V

0.47μF

0.1μF

1069-7 TA01

FREQUENCY (kHz)

10

–70

–60

–50

–40

–30

10

100

1000

1069-7 TA02

–20

–10

0

cutoff frequency of the LTC1069-7 is set by an external

clock and is equal to the clock frequency divided by 25.

The ratio of the internal sampling frequency to the cutoff

frequency is 50:1 that is, the input signal is sampled

twice per clock cycle to lower the risk of aliasing. The

LTC1069-7 can be operated from a single 5V supply up

to dual ±5V supplies.

The gain and phase response of the LTC1069-7 can be

used in digital communication systems where pulse

shaping and channel bandwidth limiting must be carried

out. Any system that requires an analog filter with linear

phase and sharper roll off than conventional Bessel filters

can use the LTC1069-7.

The LTC1069-7 has a wide dynamic range. With ±5V

supplies and an input range of 0.1VRMS to 2VRMS, the

signal-to-(noise + THD) ratio is ≥ 60dB. The wideband noise

of the LTC1069-7 is 140μVRMS.UnlikeotherLTC1069-Xfilters,

the typical passband gain of the LTC1069-7 is equal to –1V/V.

The LTC1069-7 is available in an SO-8 package.

Otherfilterresponseswithlowerpower/speedspecifications

can be obtained. Please contact LTC Marketing.

Frequency Response