LTC1064-3
Low Noise, High Frequency,
8th Order Linear Phase Lowpass Filter
FEATURES
■
■
■
■
DESCRIPTIO
■
■
■
■
8th Order Filter in a 14-Pin Package
95kHz Maximum Corner Frequency
No External Components
75:1, 150:1 and 120:1 Clock to Cutoff Frequency
Ratio
60µV
RMS
Total Wideband Noise
0.03% THD or Better
Operates from
±2.37V
to
±8V
Power Supplies
Low Total Output DC Offset
The LTC
®
1064-3 is a monolithic 8th order lowpass Bessel
filter, which provides a linear phase response over its
entire passband. An external TTL or CMOS clock pro-
grams the filter’s cutoff frequency. The clock to cutoff
frequency ratio is 75:1 (Pin 10 at V
+
) or 150:1 (Pin 10 at
V
–
) or 120:1 (Pin 10 at GND). The maximum cutoff
frequency is 95kHz. No external components are needed.
The LTC1064-3 features low wideband noise and low
harmonic distortion even for input voltages up to 3V
RMS
.
In fact the LTC1064-3 overall performance competes with
equivalent multiple op amp RC active realizations. The
LTC1064-3 is available in a 14-pin DIP or 16-pin surface
mounted SOL package. The LTC1064-3 is fabricated using
LTC’s enhanced analog CMOS Si-gate process.
The LTC1064-3 is pin compatible with the LTC1064-1,
LTC1064-2 and LTC1064-4.
, 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 Bessel Filter
1
V
IN
2
3
4
5
6
7
NC
V
IN
OUT C
NC
14
13
–8V
CLOCK = 7MHz
0.1µF
Measured Frequency Response
0
–15
–30
V
OUT
/V
IN
(dB)
LTC1064-3
12
V
–
AGND
V
+
AGND
NC
INV A
f
CLK
75/150
V
OUT
NC
11
–45
–60
–75
8V
0.1µF
10
+
V
9
8
V
OUT
1064 TA01a
–90 V
S
=
±7.5V,
f
CLK
= 7MHz, PIN 10 TO V
+
,
f
–3dB
= 95kHz, GROUP DELAY = 6µs
–105
100
10
FREQUENCY (kHz)
NOTE: THE POWER SUPPLIES SHOULD BE BYPASSED BY A 0.1µF
OR LARGER CAPACITOR CLOSE TO THE PACKAGE. THE CONNECTI0N
BETWEEN PIN 7 AND PIN 14 SHOULD BE MADE UNDER THE IC PACKAGE.
U
1000
1064-3 TA01b
U
U
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1
LTC1064-3
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
ORDER PART
NUMBER
NC
1
2
3
4
5
6
7
8
LTC1064-3CN
11 f
CLK
10 75/150
9
8
V
OUT
NC
N PACKAGE
14-LEAD PDIP
T
JMAX
= 110°C,
θ
JA
= 70°C/W
J PACKAGE
14-LEAD CERDIP
OBSOLETE PACKAGE
Consider the N 14 Package for Alternate Source
LTC1064-3MJ
LTC1064-3CJ
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS
PARAMETER
Passband Gain
Gain TempCo
–3dB Frequency
Gain at –3dB Frequency
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,
75:1, f
CLK
= 2MHz, R1 = 10k, TTL or CMOS clock input level
unless otherwise specified.
MIN
●
Referenced to 0dB, 1Hz to 1kHz
50:1 (f
CLK
/f
–3dB
= 75)
100:1 (f
CLK
/f
–3dB
= 150)
Referenced to 0dB, f
IN
= 26.67/13.34kHz
At 3f
–3dB
At 5f
–3dB
At 7f
–3dB
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
LTC1064-3M
(OBSOLETE)
............... – 55°C to 125°C
LTC1064-3C ....................................... – 40°C to 85°C
Input Voltage ........................... (V
+
+0.3V) to V
–
–0.3V)
Burn-In Voltage ....................................................... 15V
TOP VIEW
16 OUT C
15 NC
14 V
–
13 NC
12 f
CLK
11 75/150
10 NC
9
V
OUT
ORDER PART
NUMBER
LTC1064-3CSW
V
IN
AGND
V
+
AGND
NC
NC
R
IN
A
SW PACKAGE
16-LEAD PLASTIC (WIDE) SO
T
JMAX
= 150°C,
θ
JA
= 90°C/W
TYP
0.0002
26.67
13.34
MAX
0.15
UNITS
dB
dB/°C
kHz
kHz
dB
dB
dB
dB
kHz
kHz
V
V
V
–0.5
●
●
●
–3.8
–25
–56
0
0
–2.75
–29
–60
–84
<f
CLK
/2
<f
CLK
●
●
●
±1.1
±3.1
±5
0.015
0.03
55
60
%
%
µV
RMS
µV
RMS
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LTC1064-3
ELECTRICAL CHARACTERISTICS
PARAMETER
Output DC Offset
Output DC Offset TempCo
Input Impedance
Output Impedance
Output Short-Circuit Current
Clock Feedthrough
Maximum Clock Frequency
Power Supply Current
f
OUT
= 10kHz
Source/Sink
CONDITIONS
V
S
=
±7.5V
V
S
=
±5V
V
S
=
±7.5V
The
●
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
S
=
±7.5V,
75:1, f
CLK
= 2MHz, R1 = 10k, TTL or CMOS clock input level
unless otherwise specified.
MIN
TYP
±
30
±
20
±50
14
22
2
3/1
200
V
S
≥
±7V,
50% Duty Cycle
V
S
≥
±7V,
50% Duty Cycle, T
A
= <55°C
V
S
=
±2.37V,
f
CLK
= 1MHz
V
S
=
±5V,
f
CLK
= 1MHz
V
S
=
±7.5V,
f
CLK
= 1MHz
●
●
●
MAX
±150
UNITS
mV
µV/°C
µV/°C
kΩ
Ω
mA
µV
RMS
5
7
10
12
16
●
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
TYPICAL PERFOR A CE CHARACTERISTICS
Gain vs Frequency
15
0
–15
f
CLK
= 2MHz
f
–3dB
= 26.67kHz
f
CLK
= 5MHz
f –3dB = 66.67kHz
f
CLK
= 7MHz
f
–3dB
= 95kHz
GAIN (dB)
–30
–45
–60
–75
–90
PHASE (DEG)
135
180
225
270
315
360
GROUP DELAY (µs)
V
S
=
±7.5V
T
A
= 25°C
100k
FREQUENCY (Hz)
1M
1064 G01
–105
10k
U W
Phase vs Frequency
–45
0
45
90
V
S
=
±7.5V
T
A
= 25°C
f
CLK
= 750kHz
f
–3dB
= 10kHz
110
100
90
80
70
60
50
40
30
20
10
0
Group Delay
V
S
=
±7.5V
T
A
= 25°C
f
CLK
= 750kHz, f
–3dB
= 10kHz
f
CLK
= 2MHz, f
–3dB
= 26.67kHz
f
CLK
= 5MHz, f
–3dB
= 66.67kHz
0
2
4
6
8 10 12 14 16 18 20 22
FREQUENCY (kHz)
1064 G03
405
450
0
2
4
6
8 10 12 14 16 18 20 22
FREQUENCY (kHz)
1064 G02
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LTC1064-3
TYPICAL PERFOR A CE CHARACTERISTICS
Phase Matching
2.2
V
S
=
±7.5V
2.0 f
CLK
= 1.5MHz
1.8 f
–3dB
= 20kHz
50 UNIT SAMPLE (T
A
= 25°C TO 125°C)
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
0
2
4
6
8 10 12 14 16 18 20 22
FREQUENCY (kHz)
1064 G04
POWER SUPPLY CURRENT (mA)
PHASE MATCH (±DEG)
DISTORTION (%)
4
U W
V
+
V
–
GND
Total Harmonic Distortion
1.0
f
CLK
= 1.5MHz, 75:1
f
–3dB
= 20kHz
Power Supply Current vs Power
Supply Voltage
48
44
40
36
32
28
24
20
16
12
8
4
10
1064 G05
f
CLK
= 1MHz
V
S
=
±5V
0.1
V
S
=
±2.37V
T
A
= –55°C
T
A
= 25°C
T
A
= 125°C
V
S
=
±7.5V
0.01
0.1
1
INPUT LEVELS (V
RMS
)
0
0 2 4 6 8 10 12 14 16 18 20 22 24
TOTAL POWER SUPPLY VOLTAGE (V)
1064 G06
Transient Response
Input 10V
P-P
Square Wave
V
S
=
±7.5V,
Pin 10 to V
+
,
f
CLK
= 1.5MHz
Table 1. Wideband Noise (µV
RMS
)
V
S
=
±2.37V
Pin 10 to
f
CLK
/f
–3dB
75/1
150/1
120/1
Noise
µV
RMS
50
52
45
V
S
=
±5V
Noise
µV
RMS
55
58
50
V
S
=
±7.5V
Noise
µV
RMS
60
62
54
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LTC1064-3
TYPICAL PERFOR A CE CHARACTERISTICS
Table 2. Gain/Phase, f
–3dB
= 1kHz, LTC1064-3 Typical Response
V
S
=
±5V,
T
A
= 25°C, f
CLK
= 75kHz, Pin 10 at V
+
(fltr 75:1)
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)
– 0.858
– 2.990
– 6.840
– 12.780
– 20.800
– 29.900
– 38.800
– 47.100
– 54.700
– 61.600
– 68.000
– 73.840
– 79.250
– 84.230
– 88.940
– 93.360
– 97.510
–100.880
–105.780
PHASE (deg)
–90.430
179.200
89.600
3.800
–71.000
–129.600
–173.700
152.600
126.000
103.300
85.190
69.060
54.780
42.440
30.060
21.300
10.000
1.520
–7.820
Table 4. Gain/Phase, f
–3dB
= 1kHz, LTC1064-3 Typical Response
V
S
=
±5V,
T
A
= 25°C, f
CLK
= 150kHz, Pin 10 at V
–
(fltr 150:1)
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)
– 0.955
– 3.380
– 7.570
– 13.770
– 21.800
– 30.700
– 39.400
– 47.600
– 55.100
– 61.900
– 68.260
– 74.050
– 79.450
– 84.330
– 89.010
– 93.250
– 97.340
– 101.390
– 104.980
PHASE (deg)
– 88.100
–175.300
99.700
20.100
– 48.000
–100.700
–139.900
–169.200
168.300
150.300
135.830
123.660
113.440
104.440
97.670
91.580
84.670
74.600
75.990
U W
Table 3. Gain/Delay, f
–3dB
= 1kHz, LTC1064-3 Typical Response
V
S
=
±5V,
T
A
= 25°C, f
CLK
= 75kHz, Pin 10 at V
+
(fltr 75:1)
FREQUENCY (kHz)
0.200
0.300
0.400
0.500
0.600
0.700
0.800
0.900
1.000
1.100
1.200
1.300
1.400
1.500
1.600
1.700
1.800
1.900
2.000
GAIN (dB)
– 0.281
– 0.420
– 0.610
– 0.860
– 1.160
– 1.530
– 1.950
– 2.430
– 2.990
– 3.610
– 4.300
– 5.060
– 5.920
– 6.830
– 7.840
– 8.930
– 10.130
– 11.410
– 12.780
DELAY (ms)
0.502
0.503
0.503
0.502
0.502
0.502
0.503
0.503
0.500
0.500
0.500
0.498
0.495
0.491
0.489
0.481
0.473
0.465
0.454
Table 5. Gain/Delay, f
–3dB
= 1kHz, LTC1064-3 Typical Response
V
S
=
±5V,
T
A
= 25°C, f
CLK
= 150kHz, Pin 10 at V
–
(fltr 150:1)
FREQUENCY
0.200
0.300
0.400
0.500
0.600
0.700
0.800
0.900
1.000
1.100
1.200
1.300
1.400
1.500
1.600
1.700
1.800
1.900
2.000
GAIN (dB)
– 0.284
– 0.450
– 0.670
– 0.960
– 1.310
– 1.730
–2.210
–2.750
–3.380
– 4.070
– 4.820
– 5.660
– 6.580
– 7.570
– 8.640
– 9.790
– 11.050
– 12.360
– 13.770
DELAY (ms)
0.490
0.489
0.489
0.487
0.487
0.485
0.484
0.482
0.478
0.478
0.475
0.470
0.467
0.463
0.456
0.448
0.438
0.428
0.417
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