LTC1064-2
Low Noise, High Frequency,
8th Order Butterworth Lowpass Filter
FEATURES
■
■
■
■
■
■
■
DESCRIPTIO
8th Order Filter in a 14-Pin Package
140kHz Maximum Corner Frequency
No External Components
50:1 and 100:1 Clock to Cutoff Frequency Ratio
80µV
RMS
Total Wideband Noise
0.03% THD or Better
Operates from
±2.37V
to
±8V
Power Supplies
The LTC
®
1064-2 is a monolithic 8th order lowpass
Butterworth filter, which provides a maximally flat pass-
band. The attenuation slope is –48dB/octave and the
maximum attenuation is in excess of 80db. An external
TTL or CMOS clock programs the filter’s cutoff frequency.
The clock to cutoff frequency ratio is 100:1 (Pin 10 at
V
–
) or 50:1 (Pin 10 at V
+
). The maximum cutoff frequency
is 140kHz. No external components are needed.
The LTC1064-2 features low wideband noise and low
harmonic distortion even for input voltages up to 3V
RMS
.
In fact the LTC1064-2 overall performance competes with
equivalent multiple op amp RC active realizations. The
LTC1064-2 is available in a 14-pin DIP or 16-pin surface
mounted SW package. The LTC1064-2 is fabricated using
LTC’s enhanced analog CMOS Si-gate process.
The LTC1064-2 is pin compatible with the LTC1064-1.
, LTC and LT are registered trademarks of Linear Technology Corporation.
APPLICATIO S
■
■
■
Antialiasing Filters
Smoothing Filters
Tracking High Frequency Lowpass Filters
TYPICAL APPLICATIO
8th Order Clock Sweepable
Lowpass Butterworth Filter
1
14
OUT C
LTC1064-2
2
13
NC
V
IN
NC
3
8V
4
5
6
7
V
OUT
/V
IN
(dB)
Measured Frequency Response
0
V
S
=
±7.5V
–15
–30
AGND
V
+
AGND
NC
R
IN
A
V
–
f
CLK
50/100
V
OUT
NC
12
11
10
9
8
–8V
CLOCK = 5MHz
–45
–60
–75
–90
–105
1064 TA01a
0
100
NOTE: THE POWER SUPPLIES SHOULD BE BYPASSED BY A 0.1µF
CAPACITOR CLOSE TO THE PACKAGE. THE NC PINS 1, 6, 8,
AND 13 SHOULD BE PREFERABLY GROUNDED.
U
200 300 400 500
FREQUENCY (kHz)
600
700
1064-2 TA01b
U
U
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1
LTC1064-2
ABSOLUTE
AXI U RATI GS
Total Supply Voltage (V
+
to V
–
) ............................ 16.5V
Power Dissipation .............................................. 400mW
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
PACKAGE/ORDER I FOR ATIO
TOP VIEW
NC
V
IN
AGND
V
+
AGND
NC
R
IN
A
1
2
3
4
5
6
7
14 OUT C
13 NC
12 V
–
11 f
CLK
10 50/100
9
8
V
OUT
NC
ORDER PART
NUMBER
NC
1
2
3
4
5
6
7
8
LTC1064-2CN
N PACKAGE
14-LEAD PDIP
T
JMAX
= 150°C,
θ
JA
= 110°C/W
J PACKAGE
14-LEAD CERDIP
OBSOLETE PACKAGE
Consider the N14 Package for Alternate Source
LTC1064-2MJ
LTC1064-2CJ
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS
PARAMETER
Passband Gain (Note 2)
Gain TempCo
–3dB Frequency
Gain at –3dB Frequency
Stopband Attenuation
Stopband Attenuation
Stopband Attenuation
Stopband Attenuation
Input Frequency Range
Output Voltage Swing and
Operating Input Voltage Range
Total Harmonic Distortion
Wideband Noise
CONDITIONS
The
●
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
S
=
±7.5V,
100:1, f
CLK
= 2MHz, R1 = 10k, TTL clock input level unless
otherwise specified.
MIN
●
Referenced to 0dB, 1Hz to 1kHz
100:1
50:1
Referenced to 0dB, f
IN
= 20kHz
At 1.5f
–3dB
, 50:1, f
IN
= 60kHz
At 2f
–3dB
, 100:1, f
IN
= 40kHz
At 3f
–3dB
, 100:1, f
IN
= 60kHz
At 4f
–3dB
, 100:1, f
IN
= 80kHz
100:1
50:1
V
S
=
±2.37V
V
S
=
±5V
V
S
=
±7.5V
V
S
=
±5V,
Input = 1V
RMS
at 1kHz
V
S
=
±7.5V,
Input = 3V
RMS
at 1kHz
V
S
=
±5V,
Input = GND 1Hz – 1.99MHz
V
S
=
±7.5V,
Input = GND 1Hz – 1.99MHz
2
U
U
W
W W
U
W
(Note 1)
Operating Temperature Range
LTC1064-2M
(OBSOLETE)
............... – 55°C to 125°C
LTC1064-2C ....................................... – 40°C to 85°C
TOP VIEW
16 OUT C
15 NC
14 V
–
13 NC
12 f
CLK
11 50/100
10 NC
9
V
OUT
ORDER PART
NUMBER
LTC1064-2CSW
V
IN
AGND
V
+
AGND
NC
NC
R
IN
A
SW PACKAGE
16-LEAD PLASTIC (WIDE) SO
T
JMAX
= 150°C,
θ
JA
= 130°C/W
TYP
0.0002
20
40
–3
–27
–47
–74
–90
MAX
0.15
UNITS
dB
dB/°C
kHz
kHz
dB
dB
dB
dB
dB
kHz
kHz
V
V
V
–0.5
●
●
●
–2.75
–24
–44
0
0
●
●
●
<f
CLK
/2
<f
CLK
±1.1
±3.1
±5.0
0.015
0.03
80
90
%
%
µV
RMS
µV
RMS
10642fa
LTC1064-2
ELECTRICAL CHARACTERISTICS
PARAMETER
Output DC Offset (Note 2)
Output DC Offset TempCo
Input Impedance
Output Impedance
Output Short-Circuit Current
Clock Feedthrough
Maximum Clock Frequency
Power Supply Current
50% Duty Cycle, V
S
=
±5V
50% Duty Cycle, T
A
= 25°C, V
S
=
±7.5V
V
S
=
±2.37V,
f
CLK
= 1MHz
V
S
=
±5V,
f
CLK
= 1MHz
V
S
=
±7.5V,
f
CLK
= 1MHz
●
●
●
The
●
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
S
=
±7.5V,
100:1, f
CLK
= 2MHz, R1 = 10k, TTL clock input level unless
otherwise specified.
CONDITIONS
V
S
=
±7.5V
V
S
=
±5V
10
f
OUT
= 10kHz
Source/Sink
MIN
TYP
±30
±90
20
2
3/1
200
5
7
11
14
17
●
MAX
±125
UNITS
mV
µV/°C
kΩ
Ω
mA
µV
RMS
MHz
MHz
mA
mA
mA
mA
mA
V
22
23
26
28
32
±8
Power Supply Voltage Range
Note 1:
Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
±2.37
Note 2:
For tighter specifications please contact LTC Marketing.
TYPICAL PERFOR A CE CHARACTERISTICS
Amplitude Response
15
0
–15
f
CLK
= 2MHz
f–3dB = 40kHz
f
CLK
= 7MHz
f–3dB = 140kHz
45
0
–45
–90
–135
–180
–225
–270
–315
–360
V
S
=
±7.5V
T
A
= 25°C
f
CLK
= 1MHz
100:1
f
–3dB
= 10kHz
PHASE (DEG)
–30
–45
–60
–75
–90
V
S
=
±7.5V;
50:1
T
A
= 25°C
100k
f
IN
(Hz)
1M
1064 G01
GROUP DELAY (µs)
V
OUT
/V
IN
(dB)
f
CLK
= 5MHz
f–3dB = 100kHz
–105
10k
U W
Phase Response
220
Group Delay vs Frequency
V
S
=
±7.5V
200 T = 25°C
A
180 f
CLK
= 1MHz
100:1
160 f
–3dB
= 10kHz
140
120
100
80
60
40
20
0
–405
–450
0
1
2
3
4
6 7
f
IN
(kHz)
5
8
9 10 11
1064 G02
0
1
2
3
4
5 6 7
f
IN
(kHz)
8
9 10 11
1064 G03
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3
LTC1064-2
TYPICAL PERFOR A CE CHARACTERISTICS
Phase vs f
–3dB
Frequency
30
0
–30
–60
f
CLK
= 500kHz
f
–3dB
= 10kHz
f
CLK
= 1MHz
f
–3dB
= 20kHz
f
CLK
= 2MHz
f
–3dB
= 40kHz
PHASE (DEG)
1.6
1.2
0.8
0.4
0
–90
–120
–150
–180
–210
–240 V
S
=
±7.5V
50:1
–270
100
OUTPUT NOISE (nV/√Hz)
PHASE MATCH (±DEG)
1k
FREQUENCY (Hz)
Harmonic Distortion vs Frequency
0.1
f
CLK
= 1MHz, f
–3dB
= 20kHz, 50:1
±5V,
1V
RMS
INPUT
HARMONIC DISTORTION (%)
HARMONIC DISTORTION (%)
±7.5V,
3V
RMS
INPUT
0.01
0.001
1k
FREQUENCY (Hz)
Power Suppy vs Current
48
44
POWER SUPPLY CURRENT (mA)
40
36
32
28
24
20
16
12
8
4
0
0 2
4
6 8 10 12 14 16 18 20 22 24
POWER SUPPLY VOLTAGE (V)
1064 G09
V
OUT
/V
IN
(dB)
4
U W
1064 G04
Phase Matching
2.4
2.0
V
S
=
±7.5V,
f
CLK
= 1MHz, f
–3dB
= 20kHz, 50:1
50 UNIT SAMPLE (TA = 25°C TO 125°C)
1600
1400
1200
(1060)
1000
800
Noise Spectral Density
f
CLK
= 500kHz
100:1, f
–3dB
= 5kHz
f
CLK
= 2MHz
600 100:1, f
–3dB
= 20kHz
(530)
400
(335)
f
CLK
= 5MHz
200
100:1, f
–3dB
= 50kHz
0
0.1k
1k
10k
FREQUENCY (Hz)
100k
1064-2 G06
10k
0
4
8
12
16
FREQUENCY (kHz)
20
24
1064-2 G05
Harmonic Distortion vs Amplitude
1
±2.5V
±5V
0.1
±7V
0.01
f
CLK
= 1MHz, f
–3dB
= 20kHz
50:1, 1kHz INPUT
10k
20k
1064-2 G07
0.001
0.5
1.0
AMPLITUDE (V
RMS
)
5.0
1064-2 G08
Amplitude Response with Pin 10
at Ground
15
0
–15
–30
–45
–60
–75
–90
–105
1
10
f
IN
(kHz)
100
1064-2 G10
PIN 10 AT GROUND
f
CLK
=1MHz
TA = –55°C
TA = 25°C
TA = 125°C
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LTC1064-2
TYPICAL PERFOR A CE CHARACTERISTICS
Table 1. Gain/Delay, f
–3dB
= 1kHz,
LTC1064-2 Typical Response V
S
=
±5V,
T
A
= 25°C,
f
CLK
= 50kHz, Ratio = Pin 10 at V
+
(fltr 50:1)
FREQUENCY (kHz)
0.200
0.300
0.400
0.500
0.600
0.700
0.800
0.900
1.000
1.100
1.200
GAIN (dB)
–0.247
–0.270
–0.290
–0.300
–0.320
–0.370
–0.520
–1.200
–3.380
–7.530
–12.670
DELAY (ms)
0.857
0.872
0.893
0.929
0.983
1.071
1.210
1.364
1.381
1.192
0.935
Table 2. Gain, f
–3dB
= 1kHz,
LTC1064-2 Typical Response V
S
=
±5V,
T
A
= 25°C,
f
CLK
= 50kHz, Ratio = Pin 10 at V
+
(fltr 50:1)
FREQUENCY (kHz)
0.500
1.000
1.500
2.000
2.500
3.000
3.500
4.000
4.500
5.000
5.500
6.000
6.500
7.000
7.500
8.000
8.500
9.000
9.500
GAIN (dB)
–0.298
–3.380
–27.500
–47.200
–63.300
–75.190
–86.100
–95.310
–104.240
–109.650
–121.930
–123.920
–114.150
–116.990
–120.070
–113.470
–130.090
–114.770
–117.760
U W
Table 3. Gain/Delay, f
–3dB
= 1kHz,
LTC1064-2 Typical Response V
S
=
±5V,
T
A
= 25°C,
f
CLK
= 100kHz, Ratio = Pin 10 at V
–
(fltr 100:1)
FREQUENCY (kHz)
0.200
0.300
0.400
0.500
0.600
0.700
0.800
0.900
1.000
1.100
1.200
GAIN (dB)
–0.213
–0.240
–0.260
–0.280
–0.310
–0.370
–0.530
–1.200
–3.370
–7.500
–12.640
DELAY (ms)
0.821
0.837
0.858
0.893
0.947
1.034
1.172
1.325
1.346
1.158
0.899
Table 4. Gain, f
–3dB
= 1kHz,
LTC1064-2 Typical Response V
S
=
±5V,
T
A
= 25°C,
f
CLK
= 100kHz, Ratio = Pin 10 at V
–
(fltr 100:1)
FREQUENCY (kHz)
0.500
1.000
1.500
2.000
2.500
3.000
3.500
4.000
4.500
5.000
5.500
6.000
6.500
7.000
7.500
8.000
8.500
9.000
9.500
GAIN (dB)
–0.279
–3.370
–27.500
–47.200
–62.300
–75.130
–86.090
–95.210
–103.030
–108.690
–114.830
–120.540
–114.750
–116.430
–120.790
–121.290
–119.970
–120.020
–125.170
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