LTC1069-7 Datasheet, PDF (1/8 Pages) Linear Technology – Linear Phase 8th Order Lowpass Filter

LTC1069-7
Linear Phase
8th Order Lowpass Filter
FEATURES
s _{8th Order, Linear Phase Filter in SO-8 Package}
s _{Raised Cosine Amplitude Response}
s _{– 43dB Attenuation at 2× fCUTOFF}
s _{Wideband Noise: 140µVRMS}
s _{Operates from Single 5V Supply to}
±5V Power Supplies
s _{Clock-Tunable to 200kHz with ±5V Supplies}
s _{Clock-Tunable to 120kHz with Single 5V Supply}
U
APPLICATIONS
s _{Digital Communication Filter}
s _{Antialiasing Filter with Linear Phase}
s _{Smoothing Filters}
DESCRIPTION
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
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 shap-
ing 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 0.1V_RMS to 2V_RMS, the
signal-to-(noise + THD) ratio is ≥ 60dB. The wideband
noise of the LTC1069-7 is 140µV_RMS. Unlike other
LTC1069-X filters, the typical passband gain of the
LTC1069-7 is equal to –1V/V.
The LTC1069-7 is available in an SO-8 package.
Other filter responses with lower power/speed specifica-
tions can be obtained. Please contact LTC Marketing.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATION
Single 5V Supply, Linear Phase 100kHz Lowpass Filter
0.47µF
5V
0.1µF
AGND
V_OUT
V⁺
V^–
LTC1069-7
NC
NC
V_IN V_IN
CLK
V_OUT
f_CLK = 2.5MHz
1069-7 TA01
10
0
–10
– 20
– 30
– 40
– 50
– 60
– 70
10
Frequency Response
100
FREQUENCY (kHz)
1000
1069-7 TA02
1