LTC1563-2/LTC1563-3
Active RC, 4th Order
Lowpass Filter Family
U
DESCRIPTIO
FEATURES
The LTC®1563-2/LTC1563-3 are a family of extremely
easy-to-use, active RC lowpass filters with rail-to-rail
inputs and outputs and low DC offset suitable for systems
with a resolution of up to 16 bits. The LTC1563-2, with a
single resistor value, gives a unity-gain Butterworth
response. The LTC1563-3, with a single resistor value,
gives a unity-gain Bessel response. The proprietary
architecture of these parts allows for a simple resistor
calculation:
■
Extremely Easy to Use—A Single Resistor Value
Sets the Cutoff Frequency (256Hz < fC < 256kHz)
Extremely Flexible—Different Resistor Values
■
Allow Arbitrary Transfer Functions with or without
Gain (256Hz < fC < 256kHz)
■
Supports Cutoff Frequencies Up to 360kHz Using
FilterCADTM
■
LTC1563-2: Unity-Gain Butterworth Response Uses a
Single Resistor Value, Different Resistor Values
Allow Other Responses with or without Gain
LTC1563-3: Unity-Gain Bessel Response Uses a
R = 10k (256kHz/fC); fC = Cutoff Frequency
■
where fC is the desired cutoff frequency. For many appli-
cations, this formula is all that is needed to design a filter.
By simply utilizing different valued resistors, gain and
other responses are achieved.
Single Resistor Value, Different Resistor Values
Allow Other Responses with or without Gain
Rail-to-Rail Input and Output Voltages
Operates from a Single 3V (2.7V Min) to ±5V Supply
Low Noise: 36µVRMS for fC = 25.6kHz, 60µVRMS for
fC = 256kHz
fC Accuracy < ±2% (Typ)
DC Offset < 1mV
Cascadable to Form 8th Order Lowpass Filters
Available in Narrow SSOP-16 Package
■
■
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The LTC1563-X features a low power mode, for the lower
frequency applications, where the supply current is re-
duced by an order of magnitude and a near zero power
shutdown mode.
■
■
■
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The LTC1563-Xs are available in the narrow SSOP-16
package (Same footprint as an SO-8 package).
, LTC and LT are registered trademarks of Linear Technology Corporation.
FilterCAD is trademark of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
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APPLICATIO S
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Discrete RC Active Filter Replacement
■
Antialiasing Filters
■
Smoothing or Reconstruction Filters
■
Linear Phase Filtering for Data Communication
■
Phase Locked Loops
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TYPICAL APPLICATIO
Frequency Response
10
0
Single 3.3V, 256Hz to 256kHz Butterworth Lowpass Filter
3.3V
LTC1563-2
–10
0.1µF
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
V
OUT
+
LP
V
R = 10k
= 256kHz
R
R
–20
f
C
SA
LPB
NC
–30
–40
–50
–60
–70
–80
NC
R
R
R = 10M
= 256Hz
INVA
NC
INVB
NC
f
C
LPA
AGND
SB
R
NC
–
R
V
EN
V
IN
0.1µF
100
1k
10k
FREQUENCY (Hz)
100k
1M
10k
R
f
= 256kHz
C
1563 TA01
(
)
1563 TA02
156323fa
1