Final Electrical Specifications
FEATURES
s
s
LTC1563-2/LTC1563-3
Active RC, 4th Order
Lowpass Filter Family
January 2000
DESCRIPTION
The LTC
廬
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:
R = 10k (256kHz/f
C
); f
C
= Cutoff Frequency
where f
C
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.
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.
The LTC1563-Xs are available in the narrow SSOP-16
package (SO-8 footprint).
s
s
s
s
s
s
s
s
s
s
s
s
Extremely Easy to Use鈥擜 Single Resistor Value
Sets the Cutoff Frequency (2.56kHz < f
C
< 256kHz)
Extremely Flexible鈥擠ifferent Resistor Values
Allow Arbitrary Transfer Functions with or without
Gain (2.56kHz < f
C
< 256kHz)
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
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
鹵5V
Supply
Low Noise: 36碌V
RMS
for f
C
= 25.6kHz, 60碌V
RMS
for
f
C
= 256kHz
f
C
Accuracy <
鹵2%
(Typ)
DC Offset < 1mV
Cascadable to Form 8th Order Lowpass Filters
Low Power Mode, f
C
< 25.6kHz, I
SUPPLY
=1mA (Typ)
High Speed Mode, f
C
< 256kHz, I
SUPPLY
= 10mA (Typ)
Shutdown Mode, I
SUPPLY
= 1碌A(chǔ) (Typ)
Continuous Time, Active RC Filter, No Clock
APPLICATIONS
s
s
s
s
s
Replaces Discrete RC Active Filters and Modules
Antialiasing Filters
Smoothing or Reconstruction Filters
Linear Phase Filtering for Data Communication
Phase Locked Loops
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATION
Single 3.3V, 2.56kHz to 256kHz Butterworth Lowpass Filter
3.3V
0.1碌F
LTC1563-2
1
2
3
R
R
R
V
IN
1碌F
f
C
= 256kHz
4
5
6
7
8
LP
SA
NC
INVA
NC
LPA
AGND
V
鈥?/div>
V
+
LPB
NC
INVB
NC
SB
NC
EN
16
15
14
13
12
11
10
9
R
R
R
V
OUT
GAIN (dB)
10
0
鈥?0
鈥?0
鈥?0
鈥?0
鈥?0
鈥?0
鈥?0
鈥?0
1k
1563 TA01
( )
10k
R
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.
U
U
U
Frequency Response
R = 10k
f
C
= 256kHz
R = 1M
f
C
= 2.56kHz
100k
10k
FREQUENCY (Hz)
1M
1563 TA02
1
next