LTC1164-7
Low Power, Linear Phase
8th Order Lowpass Filter
FEATURES
s
s
s
s
s
s
s
s
DESCRIPTIO
Better Than Bessel Roll-Off
f
CUTOFF
up to 20kHz, Single 5V Supply
I
SUPPLY
= 2.5mA (Typ), Single 5V Supply
75dB THD + Noise with Single 5V Supply
Phase and Group Delay Response Fully Tested
Transient Response with No Ringing
Wide Dynamic Range
No External Components Needed
APPLICATI
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The LTC1164-7 is a low power, clock-tunable monolithic
8th order lowpass filter with linear passband phase and
flat group delay. The amplitude response approximates a
maximally flat passband and exhibits steeper roll-off than
an equivalent 8th order Bessel filter. For instance, at twice
the cutoff frequency the filter attains 34dB attenuation
(vs12dB for Bessel), while at three times the cutoff fre-
quency the filter attains 68dB attenuation (vs 30dB for
Bessel). The cutoff frequency of the LTC1164-7 is tuned
via an external TTL or CMOS clock.
Low power is achieved without sacrificing dynamic range.
With single 5V supply, the S/N + THD is up to 75dB.
Optimum 91dB S/N is obtained with
鹵7.5V
supplies.
The clock-to-cutoff frequency ratio of the LTC1164-7 can
be set to 50:1 (pin 10 to V
+
) or 100:1 (pin 10 to V
鈥?/div>
).
When the filter operates at the clock-to-cutoff frequency
ratio of 50:1, the input is double-sampled to lower the risk
of aliasing.
The LTC1164-7 is pin-compatible with the LTC1064-X
series and LTC1264-7.
Data Communication Filters
Time Delay Networks
Phase Matched Filters
TYPICAL APPLICATI
1
V
IN
2
3
5V
4
5
6
7
LTC1164-7
10kHz Linear Phase Lowpass Filter
14
13
12
11
10
9
8
鈥?V
CLK = 500kHz
5V
V
OUT
0
鈥?0
鈥?0
GAIN (dB)
鈥?0
鈥?0
鈥?0
鈥?0
NOTE: THE POWER SUPPLIES SHOULD BE BYPASSED
BY A 0.1碌F CAPACITOR CLOSE TO THE PACKAGE
AND ANY PRINTED CIRCUIT BOARD ASSEMBLY
SHOULD MAINTAIN A DISTANCE OF AT LEAST 0.2
INCHES BETWEEN ANY OUTPUT OR INPUT PIN AND
THE f
CLK
LINE.
1164-7 TA01
鈥?0
鈥?0
1
10
FREQUENCY (kHz)
U
Frequency Response
GAIN
150
140
130
DELAY
120
110
100
90
80
70
100
1164-7 TA02
UO
UO
DELAY (碌s)
1
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