LTC1063
DC Accurate, Clock-Tunable
5th Order Butterworth
Lowpass Filter
FEATURES
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DESCRIPTIO
Clock-Tunable Cutoff Frequency
1mV DC Offset (Typical)
80dB CMRR (Typical)
Internal or External Clock
50µV
RMS
Clock Feedthrough
100:1 Clock-to-Cutoff Frequency Ratio
95µV
RMS
Total Wideband Noise
0.01% THD at 2V
RMS
Output Level
50kHz Maximum Cutoff Frequency
Cascadable for Faster Roll-Off
Operates from
±2.375
to
±8V
Power Supplies
Self-Clocking with 1 RC
Available in 8-Pin DIP and 16-Pin SO Wide Packages
The LTC
®
1063 is the first monolithic filter providing both
clock-tunability, low DC output offset and over 12-bit DC
accuracy. The frequency response of the LTC1063 closely
approximates a 5th order Butterworth polynomial. With
appropriate PCB layout techniques the output DC offset is
typically 1mV and is constant over a wide range of clock
frequencies. With
±5V
supplies and
±4V
input voltage
range, the CMR of the device is 80dB.
The filter cutoff frequency is controlled either by an inter-
nal or external clock. The clock-to-cutoff frequency ratio is
100:1. The on-board clock is power supply independent,
and it is programmed via an external RC. The 50µV
RMS
clock feedthrough is considerably reduced over existing
monolithic filters.
The LTC1063 wideband noise is 95µV
RMS
, and it can
process large AC input signals with low distortion. With
±7.5V
supplies, for instance, the filter handles up to
4V
RMS
(92dB S/N ratio) while the standard 1kHz THD is
below 0.02%; 80dB dynamic ranges (S/N +THD) is ob-
tained with input levels between 1V
RMS
and 2.3V
RMS
.
The LTC1063 is available in 8-pin miniDIP and 16-pin SO
wide packages. For a linear phase response, see LTC1065
data sheet.
APPLICATIO S
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Audio
Strain Gauge Amplifiers
Anti-Aliasing Filters
Low Level Filtering
Digital Voltmeters
60Hz Lowpass Filters
Smoothing Filters
Reconstruction Filters
, LTC and LT are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATIO
V
IN
** 1
2
3
–5V
4
LTC1063
2.5kHz 5th Order Lowpass Filter
8
7
6
5
V
OUT
5V
0.1µF
10
0
–10
–20
GAIN (dB)
–30
–40
–50
–60
–70
0.1µF
*19.1k
200pF*
*
SELF-CLOCKING SCHEME
+
**
IF THE INPUT VOLTAGE CAN EXCEED V ,
–80
–90
+
1063 TA01
CONNECT A SIGNAL DIODE BETWEEN PIN 1 AND V .
1
U
Frequency Response
10
FREQUENCY (kHz)
100
1063 TA02
U
U
1063fa
1
LTC1063
ABSOLUTE
MAXIMUM
RATINGS
(Note 1)
Total Supply Voltage (V
+
to V
–
) .......................... 16.5V
Power Dissipation ............................................. 400mW
Voltage at Any Input .... (V
–
– 0.3V)
≤
V
IN
≤
(V
+
+ 0.3V)
Burn-In Voltage ...................................................... 16V
Operating Temperature Range ............... – 40°C to 85°C
Storage Temperature Range ................ – 65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
PACKAGE/ORDER I FOR ATIO
TOP VIEW
V
IN
1
GND 2
V
–
3
CLK OUT 4
8
7
6
5
V
OS
ADJ
V
OUT
V
+
CLK IN
ORDER PART
NUMBER
LTC1063CN8
N8 PACKAGE
8-LEAD PLASTIC DIP
T
JMAX
= 100°C,
θ
JA
= 110°C/W (N)
J8 PACKAGE
8-LEAD CERAMIC DIP
T
JMAX
= 150°C,
θ
JA
= 100°C/W (J)
LTC1063CJ8
LTC1063MJ8
OBSOLETE PACKAGE
Consider the N8 Package for Alternate Source
Order Options
Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marking:
http://www.linear.com/leadfree/
Consult LTC Marketing for parts specified with wider operating temperature ranges.
The
●
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at V
S
=
±5V,
f
CLK
= 500kHz, f
C
= 5kHz, R
L
= 10k, T
A
= 25°C, unless otherwise specified.
PARAMETER
Clock-to-Cutoff Frequency Ratio (f
CLK
/ f
C
)
Maximum Clock Frequency (Note 2)
CONDITIONS
±2.375V
≤
V
S
≤
±7.5V
V
S
=
±7.5V
V
S
=
±5V
V
S
=
±2.5V
±2.5V
≤
V
S
≤
±7.5V,
T
A
< 85°C
0
V
S
=
±5V,
f
CLK
= 25kHz, f
C
= 250Hz
f
IN
= 250Hz
V
S
=
±5V,
f
CLK
= 500kHz, f
C
= 5kHz
f
IN
= 100Hz
f
IN
= 1kHz = 0.2f
C
f
IN
= 2.5kHz = 0.5f
C
f
IN
= 4kHz = 0.8f
C
●
●
●
ELECTRICAL CHARACTERISTICS
Minimum Clock Frequency (Note 3)
Input Frequency Range
Filter Gain
2
U
U
W
W W
U
W
TOP VIEW
NC 1
V
IN
2
GND 3
NC 4
V
–
5
16 V
OS
ADJ
15 NC
14 V
OUT
13 NC
12 V
+
11 NC
10 NC
9
CLK IN
ORDER PART
NUMBER
LTC1063CSW
NC 6
NC 7
CLK OUT 8
SW PACKAGE
16-LEAD PLASTIC SO WIDE
T
JMAX
= 100°C,
θ
JA
= 85°C/W
MIN
TYP
100
±0.5
5
4
3
30
MAX
UNITS
MHz
MHz
MHz
Hz
0.9f
CLK
– 3.0
– 3.0
0
– 2.5
– 2.4
dB
dB
dB
0.04
0.055
0.41
0.46
0.1
0.2
dB
dB
dB
dB
dB
dB
1063fa
●
– 3.5
– 3.6
– 0.06
– 0.075
– 0.09
– 0.14
– 0.5
– 0.6
– 0.01
– 0.01
0.16
0.16
– 0.2
– 0.2
LTC1063
The
●
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at V
S
=
±5V,
f
CLK
= 500kHz, f
C
= 5kHz, R
L
= 10k, T
A
= 25°C, unless otherwise specified.
PARAMETER
CONDITIONS
f
IN
= 5kHz = f
C
f
IN
= 20kHz = 4f
C
●
●
ELECTRICAL CHARACTERISTICS
MIN
– 3.5
– 3.6
– 57.5
– 57.0
– 0.066
– 0.081
– 0.24
– 0.29
– 0.6
– 0.7
– 3.5
– 3.6
TYP
– 3.0
– 3.0
– 60.0
– 60.0
0.004
0.004
0.16
0.16
– 0.2
– 0.2
– 3.0
– 3.0
50
100
–80
MAX
– 2.5
– 2.4
– 62.0
– 62.5
0.074
0.089
0.56
0.61
0.2
0.3
– 2.5
– 2.4
UNITS
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
µV
RMS
µV
RMS
dB
V
V
V
V
V
V
nA
MΩ
mV
mV
mV
µV/°C
µV/°C
µV/°C
Filter Gain
V
S
=
±2.375V,
f
CLK
= 500kHz, f
C
= 5kHz
f
IN
= 1kHz
●
f
IN
= 2.5kHz
●
f
IN
= 4kHz
●
f
IN
= 5kHz
●
Clock Feedthrough
Wideband Noise (Note 4)
THD + Wideband Noise (Note 5)
Filter Output
±
DC Swing
±2.375
≤
V
S
≤
±7.5V
±2.375
≤
V
S
≤
±7.5V,
1Hz < f < f
CLK
V
S
=
±7.5V,
f
C
= 20kHz, f
IN
= 1kHz,
1V
RMS
≤
V
IN
≤
2.3V
RMS
V
S
=
±2.375V
●
1.6/– 2.0
1.4/– 1.8
4.0/– 4.5
3.8/– 4.3
6.5/– 7.0
6.3/– 6.8
1.7/– 2.2
4.3/– 4.8
6.8/– 7.3
10
800
V
S
=
±5V
●
V
S
=
±7.5V
●
Input Bias Current
Dynamic Input Impedance
Output DC Offset (Note 6)
V
S
=
±2.375V
V
S
=
±5V
V
S
=
±7.5V
V
S
=
±2.375V
V
S
=
±5V
V
S
=
±7.5V
R (Pin 4 to 5) = 20k, C (Pin 5 to GND) = 470pF
V
S
=
±2.375V
●
2
0
–4
10
20
25
99
95
102
98
104
101
105
103
108
106
110
109
1.43
0.47
3
1
4.5
1.5
±5
Output DC Offset Drift
Self-Clocking Frequency (f
OSC
)
112
114
114
114
116
116
kHz
kHz
kHz
kHz
kHz
kHz
V
V
V
V
V
V
V
S
=
±5V
●
V
S
=
±7.5V
●
External CLK Pin Logic Thresholds
V
S
=
±2.375V
V
S
=
±5V
V
S
=
±7.5V
Min Logical “1”
Max Logical “0”
Min Logical “1”
Max Logical “0”
Min Logical “1”
Max Logical “0”
1063fa
3
LTC1063
ELECTRICAL CHARACTERISTICS
PARAMETER
Power Supply Current
CONDITIONS
V
S
=
±2.375V,
f
CLK
= 500kHz
●
The
●
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at V
S
=
±5V,
f
CLK
= 500kHz, f
C
= 5kHz, R
L
= 10k, T
A
= 25°C, unless otherwise specified.
MIN
TYP
2.7
5.5
●
MAX
4.0
5.5
8
11
11
14.5
UNITS
mA
mA
mA
mA
mA
mA
V
S
=
±5V,
f
CLK
= 500kHz
V
S
=
±7.5V,
f
CLK
= 500kHz
●
7.0
Note 1:
Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2:
The maximum clock frequency criterion is arbitrarily defined as:
The frequency at which the filter AC response exhibits
≥
1dB of gain
peaking.
Note 3:
At limited temperature ranges (i.e., T
A
≤
50°C) the minimum clock
frequency can be as low as 10Hz. The minimum clock frequency is
arbitrarily defined as: the clock frequency at which the output DC offset
changes by more than 1mV.
Note 4:
The wideband noise specification does not include the clock
feedthrough.
Note 5:
To properly evaluate the filter’s harmonic distortion an inverting
output buffer is recommended as shown in the Test Circuit. An output
buffer is not necessarily needed when measuring output DC offset or
wideband noise.
Note 6:
The output DC offset is optimized for
±5V
supply. The output DC
offset shifts when the power supplies change; however this phenomenon
is repeatable and predictable.
TYPICAL PERFOR A CE CHARACTERISTICS
Self-Clocking Frequency vs R
110
100
LTC1063
90
4
R
R PINS 4 TO 5 (kΩ)
80
70
60
50
40
30
20
10
100
300
FREQUENCY (kHz)
500
1063 G01
OUTPUT OFFSET (mV)
OUTPUT OFFSET (mV)
C = 200pF
f
OSC
≅
1/RC
4
U W
5
C
Output Offset vs Clock,
Low Clock Rates
50
45
40
35
30
25
20
15
10
5
0
10
B
A
110
EXTERNAL CLOCK FREQUENCY (Hz)
210
V
S
=
±5V
A: T
A
= 25°C
B: T
A
= 85°C
5
4
3
2
1
0
–1
–2
–3
–4
–5
Output Offset vs Clock,
Medium Clock Rates
V
S
=
±7.5V
V
S
=
±5V
V
S
=
±2.5V
0
500
1000
EXTERNAL CLOCK FREQUENCY (kHz)
1063 G03
1063 G02
1063fa
LTC1063
TYPICAL PERFOR A CE CHARACTERISTICS
Gain vs Frequency; V
S
=
±2.5V
10
0
–10
–20
GAIN (dB)
–40
–50
–60
–70
–80
–90
1
V
IN
= 750mV
RMS
T
A
= 25°C
A. f
CLK
= 0.5MHz
B. f
CLK
= 1MHz
C. f
CLK
= 2MHz
A
GAIN (dB)
B
C
–40
–50
–60
–70
–80
–90
V
IN
= 1.5V
RMS
T
A
= 25°C
1
A. f
CLK
= 1MHz
B. f
CLK
= 2MHz
C. f
CLK
= 3MHz
D. f
CLK
= 4MHz
A
B C
GAIN (dB)
–30
10
INPUT FREQUENCY (kHz)
THD + Noise vs Input Voltage;
V
S
= Single 5V
1
f
IN
= 1kHz, T
A
= 25°C
5 REPRESENTATIVE UNITS
1
THD + NOISE (%)
THD + NOISE (%)
0.1
THD (%)
B
A
0.01
A. f
C
= 5kHz, f
CLK
= 0.5MHz
B. f
C
= 10kHz, f
CLK
= 1MHz
0.001
0.1
0.001
1
INPUT (V
RMS
)
THD vs Frequency; V
S
=
±5V
1
V
IN
= 1.5V
RMS
f
C
= 10kHz, f
CLK
= 1MHz
S/N = 83.5dB, T
A
= 25°C
5 REPRESENTATIVE UNITS
0.1
THD + NOISE (%)
THD (%)
B
0.01
A
0.01
THD (%)
0.001
1
5
FREQUENCY (kHz)
10
1063 G10
U W
100 200
1063 G04
Gain vs Frequency; V
S
=
±5V
10
0
–10
–20
–30
D
10
0
–10
–20
–30
–40
–50
–60
–70
–80
–90
Gain vs Frequency; V
S
=
±7.5V
D
A
B C
E
A. f
CLK
= 1MHz
B. f
CLK
= 2MHz
C. f
CLK
= 3MHz
D. f
CLK
= 4MHz
E. f
CLK
= 5MHz
V
IN
= 2.5V
RMS
T
A
= 25°C
1
10
INPUT FREQUENCY (kHz)
100 200
1063 G06
10
INPUT FREQUENCY (kHz)
100 200
1063 G05
THD vs Frequency;
V
S
= Single 5V
1
V
IN
= 0.75V
RMS
f
C
= 5kHz, f
CLK
= 500kHz
S/N = 78dB, T
A
= 25°C
5 REPRESENTATIVE UNITS
0.1
THD + Noise vs Input Voltage;
V
S
=
±5V
f
IN
= 1kHz, T
A
= 25°C
5 REPRESENTATIVE UNITS
0.1
B
A
0.01
0.01
A. f
C
= 10kHz, f
CLK
= 1MHz
B. f
C
= 20kHz, f
CLK
= 2MHz
5
1063 G07
1
2
3
FREQUENCY (kHz)
4
5
1063 G08
0.001
0.1
1
INPUT (V
RMS
)
5
1063 G09
THD + Noise vs Input Voltage;
V
S
=
±7.5V
1
f
IN
= 1kHz, T
A
= 25°C
5 REPRESENTATIVE UNITS
1
THD vs Frequency;
V
S
=
±7.5V
V
IN
= 2.5V
RMS
f
C
= 10kHz, f
CLK
= 1MHz
S/N = 88dB, T
A
= 25°C
5 REPRESENTATIVE UNITS
0.1
0.1
0.01
A. f
C
= 10kHz, f
CLK
= 1MHz
B. f
C
= 20kHz, f
CLK
= 2MHz
0.001
0.1
0.001
1
INPUT (V
RMS
)
5
1063 G11
1
5
FREQUENCY (kHz)
10
1063 G12
1063fa
5
