Final Electrical Specifications
FEATURES
s
s
LTC1563-2/LTC1563-3
Active RC, 4th Order
Lowpass Filter Family
January 2000
DESCRIPTION
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:
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—A Single Resistor Value
Sets the Cutoff Frequency (2.56kHz < f
C
< 256kHz)
Extremely Flexible—Different 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
±5V
Supply
Low Noise: 36µV
RMS
for f
C
= 25.6kHz, 60µV
RMS
for
f
C
= 256kHz
f
C
Accuracy <
±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
= 1µA (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
0.1µF
LTC1563-2
1
2
3
R
R
R
V
IN
1µF
4
5
6
7
8
LP
SA
NC
INVA
NC
LPA
AGND
V
–
10
0
V
+
LPB
NC
INVB
NC
SB
NC
EN
16
15
14
13
12
11
10
9
R
R
V
OUT
GAIN (dB)
–10
–20
–30
–40
–50
–60
R = 1M
f
C
= 2.56kHz
R = 10k
f
C
= 256kHz
R
–70
–80
1k
100k
10k
FREQUENCY (Hz)
1M
1563 TA02
10k
f
C
= 256kHz
R
( )
1563 TA01
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
1
LTC1563-2/LTC1563-3
ABSOLUTE
MAXIMUM
RATINGS
(Note 1)
PACKAGE/ORDER INFORMATION
TOP VIEW
LP 1
SA 2
NC 3
INVA 4
NC 5
LPA 6
AGND 7
V
–
8
16 V
+
15 LPB
14 NC
13 INVB
12 NC
11 SB
10 NC
9
EN
Total Supply Voltage (V
+
to V
–
) ............................... 11V
Maximum Input Voltage at
Any Pin ....................... (V
–
– 0.3V)
≤
V
PIN
≤
(V
+
+ 0.3V)
Power Dissipation .............................................. 500mW
Operating Temperature Range
LTC1563C ............................................... 0°C to 70°C
LTC1563I ............................................ – 40°C to 85°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
ORDER PART
NUMBER
LTC1563-2CGN
LTC1563-3CGN
LTC1563-2IGN
LTC1563-3IGN
GN PACKAGE
16-LEAD NARROW PLASTIC SSOP
T
JMAX
= 150°C,
θ
JA
= 135°C/ W
NOTE: PINS LABELED NC ARE NOT CONNECTED
INTERNALLY AND SHOULD BE CONNECTED TO THE
SYSTEM GROUND
Consult factory for Military grade parts.
ELECTRICAL CHARACTERISTICS
The
q
denotes specifications which apply over the full operating temperature range, otherwise specifications are TA = 25°C.
V
S
= Single 4.75V, EN pin to logic “low,” Gain = 1, R
FIL
= R11 = R21 = R31 = R12 = R22 = R32, specifications apply to both the high
speed (HS) and low power (LP) modes unless otherwise noted.
PARAMETER
CONDITIONS
Specifications for Both LTC1563-2 and LTC1563-3
Total Supply Voltage (V
S
), HS Mode
Total Supply Voltage (V
S
), LP Mode
Positive Output Voltage Swing (LPB Pin)
HS Mode
Negative Output Voltage Swing (LPB Pin)
HS Mode
Positive Output Swing (LPB Pin)
LP Mode
Negative Output Swing (LPB Pin)
LP Mode
DC Offset Voltage, HS Mode
(Section A Only)
DC Offset Voltage, LP Mode
(Section A Only)
DC Offset Voltage, HS Mode
(Input to Output, Sections A, B Cascaded)
DC Offset Voltage, LP Mode
(Input to Output, Sections A, B Cascaded)
V
S
= 3V, f
C
= 25.6kHz, R
FIL
= 100k, R
L
= 10k to GND
V
S
= 4.75V, f
C
= 25.6kHz, R
FIL
= 100k, R
L
= 10k to GND
V
S
=
±5V,
f
C
= 25.6kHz, R
FIL
= 100k, R
L
= 10k to GND
V
S
= 3V, f
C
= 25.6kHz, R
FIL
= 100k, R
L
= 10k to GND
V
S
= 4.75V, f
C
= 25.6kHz, R
FIL
= 100k, R
L
= 10k to GND
V
S
=
±5V,
f
C
= 25.6kHz, R
FIL
= 100k, R
L
= 10k to GND
V
S
= 2.7V, f
C
= 25.6kHz, R
FIL
= 100k, R
L
= 10k to GND
V
S
= 4.75V, f
C
= 25.6kHz, R
FIL
= 100k, R
L
= 10k to GND
V
S
=
±5V,
f
C
= 25.6kHz, R
FIL
= 100k, R
L
= 10k to GND
V
S
= 2.7V, f
C
= 25.6kHz, R
FIL
= 100k, R
L
= 10k to GND
V
S
= 4.75V, f
C
= 25.6kHz, R
FIL
= 100k, R
L
= 10k to GND
V
S
=
±5V,
f
C
= 25.6kHz, R
FIL
= 100k, R
L
= 10k to GND
V
S
= 3V, f
C
= 25.6kHz, R
FIL
= 100k
V
S
= 4.75V, f
C
= 25.6kHz, R
FIL
= 100k
V
S
=
±5V,
f
C
= 25.6kHz, R
FIL
= 100k
V
S
= 2.7V, f
C
= 25.6kHz, R
FIL
= 100k
V
S
= 4.75V, f
C
= 25.6kHz, R
FIL
= 100k
V
S
=
±5V,
f
C
= 25.6kHz, R
FIL
= 100k
V
S
= 3V, f
C
= 25.6kHz, R
FIL
= 100k
V
S
= 4.75V, f
C
= 25.6kHz, R
FIL
= 100k
V
S
=
±5V,
f
C
= 25.6kHz, R
FIL
= 100k
V
S
= 2.7V, f
C
= 25.6kHz, R
FIL
= 100k
V
S
= 4.75V, f
C
= 25.6kHz, R
FIL
= 100k
V
S
=
±5V,
f
C
= 25.6kHz, R
FIL
= 100k
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
MIN
3
2.7
2.9
4.55
4.8
TYP
MAX
11
11
UNITS
V
V
V
V
V
2.95
4.7
4.9
0.015
0.02
– 4.95
0.05
0.05
– 4.9
2.6
4.55
4.8
2.65
4.65
4.9
0.01
0.015
– 4.95
±1.5
±1.0
±1.5
±2
±2
±2
±1.5
±1.0
±1.5
±2
±2
±2
0.05
0.05
– 4.9
±3
±3
±3
±4
±4
±5
±3
±3
±3
±5
±5
±6
2
U
W
U
U
W W
W
V
V
V
V
V
V
V
V
V
mV
mV
mV
mV
mV
mV
mV
mV
mV
mV
mV
mV
LTC1563-2/LTC1563-3
ELECTRICAL CHARACTERISTICS
The
q
denotes specifications which apply over the full operating temperature range, otherwise specifications are TA = 25°C.
V
S
= Single 4.75V, EN pin to logic “low,” Gain = 1, R
FIL
= R11 = R21 = R31 = R12 = R22 = R32, specifications apply to both the high
speed (HS) and low power (LP) modes unless otherwise noted.
PARAMETER
DC Offset Voltage Drift, HS Mode
(Input to Output, Sections A, B)
DC Offset Voltage Drift, LP Mode
(Input to Output, Sections A, B)
AGND Voltage
Power Supply Current, HS Mode
CONDITIONS
V
S
= 3V, f
C
= 25.6kHz, R
FIL
= 100k
V
S
= 4.75V, f
C
= 25.6kHz, R
FIL
= 100k
V
S
=
±5V,
f
C
= 25.6kHz, R
FIL
= 100k
V
S
= 2.7V, f
C
= 25.6kHz, R
FIL
= 100k
V
S
= 4.75V, f
C
= 25.6kHz, R
FIL
= 100k
V
S
=
±5V,
f
C
= 25.6kHz, R
FIL
= 100k
V
S
= 4.75V, f
C
= 25.6kHz, R
FIL
= 100k
V
S
= 3V, f
C
= 25.6kHz, R
FIL
= 100k
V
S
= 4.75V, f
C
= 25.6kHz, R
FIL
= 100k
V
S
=
±5V,
f
C
= 25.6kHz, R
FIL
= 100k
V
S
= 2.7V, f
C
= 25.6kHz, R
FIL
= 100k
V
S
= 4.75V, f
C
= 25.6kHz, R
FIL
= 100k
V
S
=
±5V,
f
C
= 25.6kHz, R
FIL
= 100k
V
S
= 4.75V, f
C
= 25.6kHz, R
FIL
= 100k
V
S
= 3V
V
S
= 4.75V
V
S
=
±5V
V
S
= 3V
V
S
= 4.75V
V
S
=
±5V
V
S
= 3V
V
S
= 4.75V
V
S
=
±5V
V
S
= 3V
V
S
= 4.75V
V
S
=
±5V
V
S
= 3V
V
S
= 4.75V
V
S
=
±5V
V
S
= 2.7V
V
S
= 4.75V
V
S
=
±5V
V
S
= 3V, R
FIL
= 100k
V
S
= 4.75V, R
FIL
= 100k
V
S
=
±5V,
R
FIL
= 100k
V
S
= 3V, R
FIL
= 10k
V
S
= 4.75V, R
FIL
= 10k
V
S
=
±5V,
R
FIL
= 10k
V
S
= 2.7V, R
FIL
= 100k
V
S
= 4.75V, R
FIL
= 100k
V
S
=
±5V,
R
FIL
= 100k
Test Frequency = 2.56kHz (0.1 • f
C
)
Test Frequency = 12.8kHz (0.5 • f
C
)
MIN
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
TYP
5
5
5
5
5
5
MAX
UNITS
µV/°C
µV/°C
µV/°C
µV/°C
µV/°C
µV/°C
2.35
2.375
8.0
10.5
15
1.0
1.4
2.3
1
2.40
14
17
23
1.8
2.5
3.5
20
0.8
1
1
V
mA
mA
mA
mA
mA
mA
µA
V
V
V
V
V
V
Power Supply Current, LP Mode
Shutdown Mode Supply Current
EN Input
Logic Low Level
EN Input
Logic High Level
LP
Logic Low Level
LP
Logic High Level
LTC1563-2 Transfer Function Characteristics
Cutoff Frequency Range, f
C
HS Mode
Cutoff Frequency Range, f
C
LP Mode
Cutoff Frequency Accuracy, HS Mode
f
C
= 25.6kHz
Cutoff Frequency Accuracy, HS Mode
f
C
= 256kHz
Cutoff Frequency Accuracy, LP Mode
f
C
= 25.6kHz
Cutoff Frequency Temperature Coefficient
Passband Gain, HS Mode, f
C
= 25.6kHz
V
S
= 4.75V, R
FIL
= 100k
2.5
4.3
4.4
0.8
1
1
2.5
4.3
4.4
5
5
5
5
5
5
–1.5
–1.5
–1.5
–5
–5
–5
–3
–3
–3
– 0.2
– 0.3
±1.5
±1.5
±1.5
±1.5
±1.5
±1.5
±1.5
±1.5
±1.5
±1
0
0
0.2
0.3
256
256
256
25.6
25.6
25.6
3.5
3.5
3.5
1.5
1.5
1.5
3
3
3
V
V
V
V
V
V
kHz
kHz
kHz
kHz
kHz
kHz
%
%
%
%
%
%
%
%
%
ppm/°C
dB
dB
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
3
LTC1563-2/LTC1563-3
ELECTRICAL CHARACTERISTICS
The
q
denotes specifications which apply over the full operating temperature range, otherwise specifications are TA = 25°C.
V
S
= Single 4.75V, EN pin to logic “low,” Gain = 1, R
FIL
= R11 = R21 = R31 = R12 = R22 = R32, specifications apply to both the high
speed (HS) and low power (LP) modes unless otherwise noted.
PARAMETER
Stopband Gain, HS Mode, f
C
= 25.6kHz
V
S
= 4.75V, R
FIL
= 100k
Passband Gain, HS Mode, f
C
= 256kHz
V
S
= 4.75V, R
FIL
= 10k
Stopband Gain, HS Mode, f
C
= 256kHz
V
S
= 4.75V, R
FIL
= 10k
Passband Gain, LP Mode, f
C
= 25.6kHz
V
S
= 4.75V, R
FIL
= 100k
Stopband Gain, LP Mode, f
C
= 25.6kHz
V
S
= 4.75V, R
FIL
= 100k
LTC1563-3 Transfer Function Characteristics
Cutoff Frequency Range, f
C
HS Mode
Cutoff Frequency Range, f
C
LP Mode
Cutoff Frequency Accuracy, HS Mode
f
C
= 25.6kHz
Cutoff Frequency Accuracy, HS Mode
f
C
= 256kHz
Cutoff Frequency Accuracy, LP Mode
f
C
= 25.6kHz
Cutoff Frequency Temperature Coefficient
Passband Gain, HS Mode, f
C
= 25.6kHz
V
S
= 4.75V, R
FIL
= 100k
Stopband Gain, HS Mode, f
C
= 25.6kHz
V
S
= 4.75V, R
FIL
= 100k
Passband Gain, HS Mode, f
C
= 256kHz
V
S
= 4.75V, R
FIL
= 10k
Stopband Gain, HS Mode, f
C
= 256kHz
V
S
= 4.75V, R
FIL
= 10k
Passband Gain, LP Mode, f
C
= 25.6kHz
V
S
= 4.75V, R
FIL
= 100k
Stopband Gain, LP Mode, f
C
= 25.6kHz
V
S
= 4.75V, R
FIL
= 100k
Test Frequency = 2.56kHz (0.1 • f
C
)
Test Frequency = 12.8kHz (0.5 • f
C
)
Test Frequency = 51.2kHz (2 • f
C
)
Test Frequency = 102.4kHz (4 • f
C
)
Test Frequency = 25.6kHz (0.1 • f
C
)
Test Frequency = 128kHz (0.5 • f
C
)
Test Frequency = 400kHz (1.56 • f
C
)
Test Frequency = 500kHz (1.95 • f
C
)
Test Frequency = 2.56kHz (0.1 • f
C
)
Test Frequency = 12.8kHz (0.5 • f
C
)
Test Frequency = 51.2kHz (2 • f
C
)
Test Frequency = 102.4Hz (4 • f
C
)
V
S
= 3V
V
S
= 4.75V
V
S
=
±5V
V
S
= 2.7V
V
S
= 4.75V
V
S
=
±5V
V
S
= 3V, R
FIL
= 100k
V
S
= 4.75V, R
FIL
= 100k
V
S
=
±5V,
R
FIL
= 100k
V
S
= 3V, R
FIL
= 10k
V
S
= 4.75V, R
FIL
= 10
V
S
=
±5V,
R
FIL
= 10k
V
S
= 2.7V, R
FIL
= 100k
V
S
= 4.75V, R
FIL
= 100k
V
S
=
±5V,
R
FIL
= 100k
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
CONDITIONS
Test Frequency = 51.2kHz (2 • f
C
)
Test Frequency = 102.4kHz (4 • f
C
)
Test Frequency = 25.6kHz (0.1 • f
C
)
Test Frequency = 128kHz (0.5 • f
C
)
Test Frequency = 400kHz (1.56 • f
C
)
Test Frequency = 500kHz (1.95 • f
C
)
Test Frequency = 2.56kHz (0.1 • f
C
)
Test Frequency = 12.8kHz (0.5 • f
C
)
Test Frequency = 51.2kHz (2 • f
C
)
Test Frequency = 102.4kHz (4 • f
C
)
MIN
q
q
q
q
q
q
q
q
q
q
TYP
– 24
– 48
0
0
– 15.7
– 23.3
MAX
– 21.5
– 46
0.2
0.5
–13.5
– 21.5
0.25
0.6
– 22
– 46.5
256
256
256
25.6
25.6
25.6
UNITS
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
kHz
kHz
kHz
kHz
kHz
kHz
%
%
%
%
%
%
%
%
%
ppm/°C
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
– 0.2
– 0.5
– 0.25
– 0.6
0
– 0.02
– 24
– 48
5
5
5
5
5
5
–2
–2
–2
–2
–2
–2
–3
–3
–3
– 0.2
–1.0
±2
±2
±2
±2
±2
±2
±3
±3
±3
±1
– 0.03
– 0.72
–13.6
– 34.7
– 0.2
–1.1
– 0.03
– 0.72
– 8.3
– 13
– 0.2
–1.0
– 0.03
– 0.72
– 13.6
– 34.7
5.5
5.5
5.5
6
6
6
7
7
7
0.2
– 0.25
–10
– 31
0.2
– 0.5
–6
–10.5
0.2
– 0.25
–11
– 32
Note 1:
Absolute Maximum Ratings are those value beyond which the life
of a device may be impaired.
4
LTC1563-2/LTC1563-3
PIN FUNCTIONS
LP (Pin 1):
Low Power. The LTC1563-X has two operating
modes. Most applications use the part’s High Speed
operating mode. Some lower frequency, lower gain appli-
cations can take advantage of the Low Power mode. When
placed in the Low Power mode, the supply current is nearly
an order of magnitude lower than the High Speed mode.
Refer to the Applications Information section for more
information on the Low Power mode.
The LTC1563-X is in the High Speed mode when the
LP input is at a logic high level or is open-circuited. A small
pull-up current source at the LP input defaults the
LTC1563-X to the High Speed mode if the pin is left open.
The part is in the Low Power mode when the pin is pulled
to a logic low level or connected to V
–
.
SA, SB (Pins 2, 11):
Summing Pins. These pins are a
summing point for signals fed forward and backward.
Capacitance on the SA or SB pin will cause excess peaking
of the frequency response near the cutoff frequency. The
three external resistors for each section should be located
as close as possible to the summing pin to minimize this
effect. Refer to the Applications Information section for
more details.
NC (Pins 3, 5, 10, 12, 14):
These pins are not connected
internally. For best performance, they should be con-
nected to ground.
INVA, INVB (Pins 4, 13):
Inverting Input. Each of the INV
pins is an inverting input of an op amp. Note that the INV
pins are high impedance, sensitive nodes of the filter and
very susceptible to coupling of unintended signals.
Capacitance on the INV nodes will also affect the fre-
quency response of the filter sections. For these reasons,
printed circuit connections to the INV pins must be kept as
short as possible.
LPA, LPB (Pins 6, 15):
Lowpass Output. These pins are
the rail-to-rail outputs of an op amp. Each output is
designed to drive a nominal net load of 5kΩ and 20pF.
Refer to the Applications Information section for more
details on output loading effects.
AGND (Pin 7):
Analog Ground. The AGND pin is the
midpoint of an internal resistive voltage divider developing
a potential halfway between the V
+
and V
–
pins. The
equivalent series resistance is nominally 10kΩ. This serves
as an internal ground reference. Filter performance will
reflect the quality of the analog signal ground. An analog
ground plane surrounding the package is recommended.
The analog ground plane should be connected to any
digital ground at a single point. Figures 1 and 2 show the
proper connections for dual and single supply operation.
V
–
, V
+
(Pins 8, 16):
The V
–
and V
+
pins should be
bypassed with 0.1µF capacitors to an adequate analog
ground or ground plane. These capacitors should be
connected as closely as possible to the supply pins. Low
noise linear supplies are recommended. Switching sup-
plies are not recommended as they will decrease the
filter’s dynamic range. Refer to Figures 1 and 2 for the
proper connections for dual and single supply operation.
EN (Pin 9):
ENABLE. When the EN input goes high or is
open-circuited, the LTC1563-X enters a shutdown state
and only junction leakage currents flow. The AGND pin, the
LPA output and the LPB output assume high impedance
states. If an input signal is applied to a complete filter
circuit while the LTC1563-X is in shutdown, some signal
will normally flow to the output through passive compo-
nents around the inactive part.
A small internal pull-up current source at the EN input
defaults the LTC1563 to the shutdown state if the EN pin
is left floating.
Therefore, the user
must
connect the EN pin
to V
–
(or a logic low) to enable the part for normal
operation.
U
U
U
5
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