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1
LTC1164-7
Low Power, Linear Phase
8th Order Lowpass Filter
U
A
O
PPLICATI
TYPICAL
S
FEATURE
s
Better Than Bessel Roll-Off
s
f
CUTOFF
up to 20kHz, Single 5V Supply
s
I
SUPPLY
= 2.5mA (Typ), Single 5V Supply
s
75dB THD + Noise with Single 5V Supply
s
Phase and Group Delay Response Fully Tested
s
Transient Response with No Ringing
s
Wide Dynamic Range
s
No External Components Needed
D
U
ESCRIPTIO
The LTC1164-7 is a low power, clock-tunable monolithic
8th order lowpass filter with linear passband phase and
flat group delay. The amplitude response approximates a
maximally flat passband and exhibits steeper roll-off than
an equivalent 8th order Bessel filter. For instance, at twice
the cutoff frequency the filter attains 34dB attenuation
(vs12dB for Bessel), while at three times the cutoff fre-
quency the filter attains 68dB attenuation (vs 30dB for
Bessel). The cutoff frequency of the LTC1164-7 is tuned
via an external TTL or CMOS clock.
Low power is achieved without sacrificing dynamic range.
With single 5V supply, the S/N + THD is up to 75dB.
Optimum 91dB S/N is obtained with
7.5V supplies.
The clock-to-cutoff frequency ratio of the LTC1164-7 can
be set to 50:1 (pin 10 to V
+
) or 100:1 (pin 10 to V
).
When the filter operates at the clock-to-cutoff frequency
ratio of 50:1, the input is double-sampled to lower the risk
of aliasing.
The LTC1164-7 is pin-compatible with the LTC1064-X
series and LTC1264-7.
10kHz Linear Phase Lowpass Filter
Frequency Response
s
Data Communication Filters
s
Time Delay Networks
s
Phase Matched Filters
U
S
A
O
PPLICATI
1
2
3
4
5
6
7
14
13
12
11
10
9
8
LTC1164-7
V
IN
5V
5V
CLK = 500kHz
5V
V
OUT
1164-7 TA01
NOTE: THE POWER SUPPLIES SHOULD BE BYPASSED
BY A 0.1
F CAPACITOR CLOSE TO THE PACKAGE
AND ANY PRINTED CIRCUIT BOARD ASSEMBLY
SHOULD MAINTAIN A DISTANCE OF AT LEAST 0.2
INCHES BETWEEN ANY OUTPUT OR INPUT PIN AND
THE f
CLK
LINE.
FREQUENCY (kHz)
1
GAIN (dB)
0
10
20
30
40
50
60
70
80
10
100
1164-7 TA02
150
140
130
120
110
100
90
80
70
DELAY (
s)
DELAY
GAIN
2
LTC1164-7
A
U
G
W
A
W
U
W
A
R
BSOLUTE
XI
TI
S
Total Supply Voltage (V
+
to V
) ............................. 16V
Power Dissipation ............................................. 400mW
Burn-In Voltage ...................................................... 16V
Voltage at Any Input ..... (V
0.3V)
V
IN
(V
+
+ 0.3V)
Storage Temperature Range ................ 65
C to 150
C
Operating Temperature Range
LTC1164-7C ...................................... 40
C to 85
C
LTC1164-7M ................................... 55
C to 125
C
Lead Temperature (Soldering, 10 sec) ................ 300
C
ELECTRICAL C
C
HARA TERISTICS
V
S
=
7.5V, R
L
= 10k, T
A
= 25
C, f
CUTOFF
= 8kHz or 4kHz, f
CLK
= 400kHz, TTL or CMOS level and all gain measurements are referenced
to passband gain, unless otherwise specified. (Maximum clock rise or fall time
1
s)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Passband Gain
0.1Hz
f
0.25 f
CUTOFF
f
TEST
= 2kHz, (f
CLK
/ f
C
) = 50:1 (Note 4)
q
0.50
0.10
0.30
dB
Gain at 0.50 f
CUTOFF
(Note 3)
f
TEST
= 4kHz, (f
CLK
/ f
C
) = 50:1
q
0.50
0.20
0.30
dB
f
TEST
= 2kHz, (f
CLK
/ f
C
) = 100:1
q
0.85
0.65
0.15
dB
Gain at 0.75 f
CUTOFF
f
TEST
= 6kHz, (f
CLK
/ f
C
) = 50:1
q
1.2
1.1
0.1
dB
Gain at f
CUTOFF
f
TEST
= 8kHz, (f
CLK
/ f
C
) = 50:1
q
4.1
3.4
1.9
dB
f
TEST
= 4kHz, (f
CLK
/ f
C
) = 100:1
q
5.5
5.2
2.5
dB
Gain at 2.0 f
CUTOFF
f
TEST
= 16kHz, (f
CLK
/ f
C
) = 50:1
q
37
34
30
dB
f
TEST
= 8kHz, (f
CLK
/ f
C
) = 100:1
q
38
34
30
dB
Gain with f
CLK
= 20kHz
f
TEST
= 200Hz, (f
CLK
/ f
C
) = 100:1
5.7
5.2
2.5
dB
Gain with f
CLK
= 400kHz, V
S
=
2.375V
f
TEST
= 4kHz, (f
CLK
/ f
C
) = 50:1
0.50
0.2
0.2
dB
f
TEST
= 8kHz, (f
CLK
/ f
C
) = 50:1
3.75
3.4
2.5
dB
Phase Factor (
F )
0.1Hz
f
f
CUTOFF
Phase = 180
F (f/f
C
)
(f
CLK
/ f
C
) = 50:1
435
2
Deg
(Note 1)
(f
CLK
/ f
C
) = 100:1
428
2
Deg
(f
CLK
/ f
C
) = 50:1
q
430
442
Deg
(f
CLK
/ f
C
) = 100:1
q
423
434
Deg
Phase Nonlinearity
(f
CLK
/ f
C
) = 50:1
1.0
%
(Note 1)
(f
CLK
/ f
C
) = 100:1
1.0
%
(f
CLK
/ f
C
) = 50:1
q
2.0
%
(f
CLK
/ f
C
) = 100:1
q
2.5
%
W
U
U
PACKAGE/ORDER I FOR ATIO
T
JMAX
= 110
C,
JA
= 85
C/W
T
JMAX
= 150
C,
JA
= 65
C/W (J)
T
JMAX
= 110
C,
JA
= 65
C/W (N)
1
2
3
4
5
6
7
TOP VIEW
N PACKAGE
14-LEAD PLASTIC DIP
14
13
12
11
10
9
8
NC
V
IN
GND
V
+
GND
LP6
CONNECT 1
CONNECT 2
NC
V
f
CLK
50/100
V
OUT
NC
J PACKAGE
14-LEAD CERAMIC DIP
TOP VIEW
S PACKAGE
16-LEAD PLASTIC SOL
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
NC
V
IN
GND
V
+
GND
NC
LP6
CONNECT 1
CONNECT 2
NC
V
NC
f
CLK
50/100
NC
V
OUT
ORDER PART
NUMBER
LTC1164-7CS
ORDER PART
NUMBER
LTC1164-7CN
LTC1164-7CJ
LTC1164-7MJ
3
LTC1164-7
ELECTRICAL C
C
HARA TERISTICS
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Group Delay (t
d
)
(f
CLK
/f
C
) = 50:1, f
f
CUTOFF
151.0
1
s
t
d
= (1/360)(f/f
C
)
(f
CLK
/f
C
) = 100:1, f
f
CUTOFF
297.2
1
s
(Note 2)
(f
CLK
/f
C
) = 50:1, f
f
CUTOFF
q
149.3
153.5
s
(f
CLK
/f
C
) = 100:1, f
f
CUTOFF
q
293.8
301.4
s
Group Delay Deviation
(f
CLK
/f
C
) = 50:1, f
f
CUTOFF
1.0
%
(Note 2)
(f
CLK
/f
C
) = 100:1, f
f
CUTOFF
1.0
%
(f
CLK
/f
C
) = 50:1, f
f
CUTOFF
q
2.0
%
(f
CLK
/f
C
) = 100:1, f
f
CUTOFF
q
2.5
%
Input Frequency Range (Table 9)
(f
CLK
/f
C
) = 50:1
<f
CLK
kHz
(f
CLK
/f
C
) = 100:1
<f
CLK
/2
kHz
Maximum f
CLK
V
S
= Single 5V (Pins 3 and 5 at 2V)
1
MHz
V
S
=
5V
1
MHz
V
S
=
7.5V
1
MHz
Clock Feedthrough (f = f
CLK
)
50:1,
5V, Input at GND
100
V
RMS
Wideband Noise
V
S
=
2.5V
95
5%
V
RMS
(1Hz
f < f
CLK
)
V
S
=
5V
105
5%
V
RMS
V
S
=
7.5V
115
5%
V
RMS
Input Impedance
35
55
90
k
Output DC Voltage Swing (Note 4)
V
S
=
2.375V
1.25
1.4
V
V
S
=
5V
q
3.70
3.9
V
V
S
=
7.5V
q
5.40
6.1
V
Output DC Offset
50:1, V
S
=
5V
100
220
mV
100:1, V
S
=
5V
100
mV
Output DC Offset TempCo
50:1, V
S
=
5V
200
V/
C
100:1, V
S
=
5V
200
V/
C
Power Supply Current
V
S
=
2.375V, T
A
= 25
C
2.5
4.0
mA
q
4.5
mA
V
S
=
5V, T
A
= 25
C
4.5
7.0
mA
q
8.0
mA
V
S
=
7.5V, T
A
= 25
C
7.0
11.0
mA
q
12.5
mA
Power Supply Range
2.375
8
V
The
q
denotes specifications which apply over the full operating temperature range.
Note 1: Input frequencies, f, are linearly phase shifted through the filter as long as
f
f
C
; f
C
= cutoff frequency.
Figure 1 curve shows the typical phase response of an LTC1164-7 operating at
f
CLK
= 400kHz, f
C
= 8kHz and it closely matches an ideal straight line. The phase
shift is described by: phase shift = 180
F (f/f
C
); f
f
C
.
F is arbitrarily called the "phase factor" expressed in degrees. The phase factor
together with the specified deviation from the ideal straight line allows the
calculation of the phase at a given frequency. Example: The phase shift at 7kHz of
the LTC1164-7 shown in Figure 1 is: phase shift = 180
434
(7kHz/10kHz)
nonlinearity = 123.8
1% or 123.9
1.24
.
Note 2: Group delay and group delay deviation are calculated from the measured
phase factor and phase deviation specifications.
Note 3: The filter cutoff frequency is abbreviated as f
CUTOFF
or f
C
.
Note 4: The AC swing is typically 11V
P-P
, 7V
P-P
, 2.8V
P-P
for
7.5V,
5V,
2.5V
supply respectively. For more information refer to the THD + Noise vs Input graphs.
V
S
=
7.5V, R
L
= 10k, T
A
= 25
C, f
CUTOFF
= 8kHz or 4kHz, f
CLK
= 400kHz, TTL or CMOS level and all gain measurements are referenced
to passband gain, unless otherwise specified. (Maximum clock rise or fall time
1
s)
Figure 1. Phase Response in the Passband (Note 1)
FREQUENCY (kHz)
0
360
PHASE (DEG)
270
180
90
0
90
180
2
4
6
8
1164-7 F01
10
1
3
5
7
9
f
CLK
= 500kHz
(f
CLK
/f
C
) = 50:1
4
LTC1164-7
C
C
HARA TERISTICS
U
W
A
TYPICAL PERFOR
CE
Gain vs Frequency
FREQUENCY (kHz)
0.1
50
GAIN (dB)
40
30
20
10
1
10
100
1264-7 G01
60
70
90
0
80
10
110
100
V
S
= 5V
f
CLK
= 500kHz
T
A
= 25C
100:1
50:1
Phase Factor vs f
CLK
(Typical Unit)
Phase Factor vs f
CLK
(Min and
Max Representative Units)
Phase Factor vs f
CLK
(Min and
Max Representative Units)
Passband Gain and Phase
Phase Factor vs f
CLK
(Typical Unit)
f
CLK
(MHz)
0.25
PHASE FACTOR
437
438
1164-7 G02
436
435
0.5
0.75
1.0
0C
70C
25C
V
S
= 5V
(f
CLK
/f
C
) = 50:1
f
CLK
(MHz)
0.25
PHASE FACTOR
432
436
1164-7 G03
429
426
0.5
0.75
1.0
0C
70C
435
434
433
431
430
428
427
25C
V
S
= 5V
(f
CLK
/f
C
) = 100:1
FREQUENCY (kHz)
1
90
GAIN (dB)
70
50
30
10
10
100
1164-7 G06
80
60
40
20
0
10
V
S
= SINGLE 5V
f
CLK
= 1MHz
f
C
= 10kHz
(f
CLK
/f
C
) = 50:1
T
A
= 25C
Gain vs Frequency
FREQUENCY (Hz)
200
GAIN (dB)
5
1000
1164-7 G07
10
15
600
800
0
90
90
180
PHASE (DEG)
5
0
20
270
180
400
GAIN
V
S
= 5V
f
CLK
= 50kHz
f
C
= 1kHz
(f
CLK
/f
C
) = 50:1
PHASE
Passband Gain and Phase
FREQUENCY (Hz)
200
GAIN (dB)
5
1000
1164-7 G08
10
15
600
800
0
90
90
180
PHASE (DEG)
5
0
20
270
180
400
PHASE
GAIN
V
S
= 5V
f
CLK
= 100kHz
f
C
= 1kHz
(f
CLK
/f
C
) = 100:1
f
CLK
(MHz)
0.25
PHASE FACTOR
436
438
1164-7 G05
433
0.5
0.75
1.0
437
435
434
V
S
= SINGLE 5V
PINS 3, 5 AT 2V
(f
CLK
/f
C
) = 50:1
T
A
= 25C
f
CLK
(MHz)
0.25
PHASE FACTOR
436
438
1164-7 G04
433
0.5
0.75
1.0
437
435
434
V
S
= 5V
(f
CLK
/f
C
) = 50:1
T
A
= 25C
5
LTC1164-7
C
C
HARA TERISTICS
U
W
A
TYPICAL PERFOR
CE
Delay vs Frequency and f
CLK
Delay vs Frequency and f
CLK
THD + Noise vs Frequency
THD + Noise vs Frequency
FREQUENCY (kHz)
2
0
DELAY (
s)
50
100
150
200
250
6
10
14
18
1264-7 G13
22
V
S
= 5V
(f
CLK
/f
C
) = 50:1
T
A
= 25C
4
12
8
16
20
A
D
B
C
A. f
CLK
= 250kHz
B. f
CLK
= 500kHz
C. f
CLK
= 750kHz
D. f
CLK
= 1000kHz
FREQUENCY (kHz)
1
THD + NOISE (dB)
2
5
1164-7 G17
3
4
90
80
45
75
65
55
40
50
60
70
85
V
S
= 7.5V
V
IN
= 2V
RMS
f
CLK
= 500kHz
(f
CLK
/f
C
) = 100:1
(5 REPRESENTA-
TIVE UNITS)
Passband Gain vs Frequency
and f
CLK
FREQUENCY (kHz)
1
5
GAIN (dB)
3
1
1
3
10
100
1164-7 G09
4
2
0
2
4
D
V
S
= 5V
f
C
= 5kHz
(f
CLK
/f
C
) = 50:1
T
A
= 25C
5
B
A. f
CLK
= 250kHz
B. f
CLK
= 500kHz
C. f
CLK
= 750kHz
D. f
CLK
= 1000kHz
A
C
Passband Gain vs Frequency
and f
CLK
FREQUENCY (kHz)
1
5
GAIN (dB)
3
1
1
3
10
100
1164-7 G11
4
2
0
2
4
V
S
= 5V
(f
CLK
/f
C
) = 100:1
T
A
= 25C
5
A. f
CLK
= 250kHz
B. f
CLK
= 500kHz
C. f
CLK
= 750kHz
D. f
CLK
= 1000kHz
A
B
C D
Passband Gain vs Frequency
and f
CLK
Passband Gain vs Frequency
and f
CLK
FREQUENCY (kHz)
1
0
DELAY (
s)
50
100
150
200
250
3
5
7
9
1264-7 G14
11
2
6
4
8
10
C
V
S
= 5V
(f
CLK
/f
C
) = 100:1
T
A
= 25C
A. f
CLK
= 250kHz
B. f
CLK
= 500kHz
C. f
CLK
= 750kHz
D. f
CLK
= 1000kHz
300
350
400
450
500
A
B
D
FREQUENCY (kHz)
1
90
THD + NOISE (dB)
80
45
5
1164-7 G15
75
65
55
40
10
V
S
= 7.5V
V
IN
= 2V
RMS
f
CLK
= 500kHz
(f
CLK
/f
C
) = 50:1
(5 REPRESENTA-
TIVE UNITS)
50
60
70
85
FREQUENCY (kHz)
1
90
THD + NOISE (dB)
80
45
5
1164-7 G16
75
65
55
40
10
V
S
= 5V
V
IN
= 1V
RMS
f
CLK
= 500kHz
(f
CLK
/f
C
) = 50:1
(5 REPRESENTA-
TIVE UNITS)
50
60
70
85
THD + Noise vs Frequency
FREQUENCY (kHz)
1
5
GAIN (dB)
3
1
1
3
10
100
1164-7 G10
4
2
0
2
4
D
V
S
= 5V
(f
CLK
/f
C
) = 50:1
T
A
= 85C
5
B
A. f
CLK
= 250kHz
B. f
CLK
= 500kHz
C. f
CLK
= 750kHz
D. f
CLK
= 1000kHz
A
C
FREQUENCY (kHz)
1
5
GAIN (dB)
3
1
1
3
10
100
1164-7 G12
4
2
0
2
4
5
V
S
= SINGLE 5V
(f
CLK
/f
C
) = 50:1
T
A
= 85C
A. f
CLK
= 250kHz
B. f
CLK
= 500kHz
C. f
CLK
= 750kHz
D. f
CLK
= 1000kHz
A
B
C
D
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