LINER LTC1164-7 Low power, linear phase 8th order lowpass filter Datasheet

LTC1164-7
Low Power, Linear Phase
8th Order Lowpass Filter
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FEATURES
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DESCRIPTIO
Better Than Bessel Roll-Off
fCUTOFF up to 20kHz, Single 5V Supply
ISUPPLY = 2.5mA (Typ), Single 5V Supply
75dB THD + Noise with Single 5V Supply
Phase and Group Delay Response Fully Tested
Transient Response with No Ringing
Wide Dynamic Range
No External Components Needed
Available in 14-Lead N and 16-Lead SW Packages
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APPLICATIO S
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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 frequency 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.
Data Communication Filters
Time Delay Networks
Phase Matched Filters
, LTC and LT are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
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.
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TYPICAL APPLICATIO
Frequency Response
10kHz Linear Phase Lowpass Filter
13
3
12
4
5
LTC1164-7
11
10
6
9
7
8
GAIN
0
NOTE: THE POWER SUPPLIES SHOULD BE BYPASSED
BY A 0.1µF 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 fCLK LINE.
1164-7 TA01
130
–20
CLK = 500kHz
VOUT
140
–10
–5V
5V
150
DELAY
–30
120
–40
110
–50
100
–60
90
–70
80
–80
70
1
10
FREQUENCY (kHz)
DELAY (µs)
5V
14
2
GAIN (dB)
VIN
1
100
1164-7 TA02
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LTC1164-7
W W
W
AXI U
+
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ABSOLUTE
RATI GS (Note 1)
–
Total Supply Voltage (V to V ) ............................. 16V
Power Dissipation ............................................. 400mW
Burn-In Voltage ...................................................... 16V
Voltage at Any Input ..... (V – – 0.3V) ≤ VIN ≤ (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
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W
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PACKAGE/ORDER I FOR ATIO
TOP VIEW
ORDER PART
NUMBER
1
14 CONNECT 2
VIN
2
13 NC
NC 1
16 CONNECT 2
GND
3
12
V–
VIN 2
15 NC
+
4
11 fCLK
GND 3
14 V –
V+
13 NC
V
GND
5
10 50/100
LP6
6
9
VOUT
CONNECT 1
7
8
NC
LTC1164-7CN
J PACKAGE 14-LEAD CERAMIC DIP
TJMAX = 150°C, θJA = 65°C/W (J)
= 150°C, θ = 65°C/W (J)
TJMAX
TJMAX = 110°C, θJAJA = 65°C/W (N)
OBSOLETE PACKAGE
Consider the N Package as an Alternate Source
4
GND 5
11 50/100
LP6 7
10 NC
CONNECT 1 8
LTC1164-7CJ
LTC1164-7MJ
LTC1164-7CSW
12 fCLK
NC 6
N PACKAGE
14-LEAD PLASTIC DIP
ORDER PART
NUMBER
TOP VIEW
NC
9
VOUT
SW PACKAGE
16-LEAD PLASTIC SO (WIDE)
TJMAX = 110°C, θJA = 85°C/W
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.
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VS = ±7.5V, RL = 10k, f CUTOFF = 8kHz or 4kHz, fCLK = 400kHz, TTL or CMOS
level and all gain measurements are referenced to passband gain, unless otherwise specified. (Maximum clock rise or fall time ≤ 1µs.)
The filter cutoff frequency is abbreviated as fCUTOFF or fC.
PARAMETER
Passband Gain
Gain at 0.50 fCUTOFF
Gain at 0.75 fCUTOFF
Gain at fCUTOFF
Gain at 2.0 fCUTOFF
Gain with fCLK = 20kHz
Gain with fCLK = 400kHz, VS = ±2.375V
Phase Factor (F )
Phase = 180° – F (f/fC)
(Note 2)
Phase Nonlinearity
(Note 2)
CONDITIONS
0.1Hz ≤ f ≤ 0.25 fCUTOFF
fTEST = 2kHz, (fCLK / fC) = 50:1
fTEST = 4kHz, (fCLK / fC) = 50:1
fTEST = 2kHz, (fCLK / fC) = 100:1
fTEST = 6kHz, (fCLK / fC) = 50:1
fTEST = 8kHz, (fCLK / fC) = 50:1
fTEST = 4kHz, (fCLK / fC) = 100:1
fTEST = 16kHz, (fCLK / fC) = 50:1
fTEST = 8kHz, (fCLK / fC) = 100:1
fTEST = 200Hz, (fCLK / fC) = 100:1
fTEST = 4kHz, (fCLK / fC) = 50:1
fTEST = 8kHz, (fCLK / fC) = 50:1
0.1Hz ≤ f ≤ fCUTOFF
(fCLK / fC) = 50:1
(fCLK / fC) = 100:1
(fCLK / fC) = 50:1
(fCLK / fC) = 100:1
(fCLK / fC) = 50:1
(fCLK / fC) = 100:1
(fCLK / fC) = 50:1
(fCLK / fC) = 100:1
●
●
●
●
●
●
●
●
●
●
●
●
MIN
TYP
MAX
UNITS
– 0.50
– 0.50
– 0.85
– 1.2
– 4.1
– 5.5
– 37
– 38
– 5.7
– 0.50
– 3.75
– 0.10
– 0.20
– 0.65
–1.1
– 3.4
– 5.2
– 34
– 34
– 5.2
– 0.2
– 3.4
0.30
0.30
0.15
0.1
–1.9
– 2.5
– 30
– 30
– 2.5
0.2
– 2.5
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
435 ± 2
428 ± 2
430
423
442
434
±1.0
±1.0
± 2.0
± 2.5
Deg
Deg
Deg
Deg
%
%
%
%
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LTC1164-7
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VS = ±7.5V, RL = 10k, f CUTOFF = 8kHz or 4kHz, fCLK = 400kHz, TTL or CMOS
level and all gain measurements are referenced to passband gain, unless otherwise specified. (Maximum clock rise or fall time ≤ 1µs.)
The filter cutoff frequency is abbreviated as fCUTOFF or fC.
PARAMETER
Group Delay (td)
td = (1/360)(f/fC)
(Note 3)
Group Delay Deviation
(Note 3)
Input Frequency Range (Table 9)
Maximum fCLK
Clock Feedthrough (f = fCLK)
Wideband Noise
(1Hz ≤ f < fCLK)
Input Impedance
Output DC Voltage Swing (Note 4)
Output DC Offset
Output DC Offset TempCo
Power Supply Current
CONDITIONS
(fCLK/fC) = 50:1, f ≥ f CUTOFF
(fCLK/fC) = 100:1, f ≥ fCUTOFF
(fCLK/fC) = 50:1, f ≥ f CUTOFF
(fCLK/fC) = 100:1, f ≥ fCUTOFF
(fCLK/fC) = 50:1, f ≥ f CUTOFF
(fCLK/fC) = 100:1, f ≥ fCUTOFF
(fCLK/fC) = 50:1, f ≥ f CUTOFF
(fCLK/fC) = 100:1, f ≥ fCUTOFF
(fCLK/fC) = 50:1
(fCLK/fC) = 100:1
VS = Single 5V (Pins 3 and 5 at 2V)
VS = ±5V
VS = ± 7.5V
50:1, ±5V, Input at GND
VS = ±2.5V
VS = ±5V
VS = ± 7.5V
MIN
●
●
TYP
151.0 ± 1
297.2 ± 1
MAX
149.3
293.8
153.5
301.4
±1.0
±1.0
± 2.0
± 2.5
●
●
VS = ±2.375V
VS = ±5V
VS = ±7.5V
50:1, VS = ±5V
100:1, VS = ±5V
50:1, VS = ±5V
100:1, VS = ±5V
VS = ±2.375V, TA = 25°C
35
±1.25
±3.70
±5.40
●
●
<fCLK
<fCLK /2
1
1
1
100
95 ± 5%
105 ± 5%
115 ± 5%
55
±1.4
±3.9
±6.1
±100
±100
±200
±200
2.5
90
±220
4.0
4.5
7.0
8.0
11.0
12.5
±8
●
VS = ±5V, TA = 25°C
4.5
●
VS = ±7.5V, TA = 25°C
7.0
●
±2.375
Power Supply Range
180
fCLK = 500kHz
(fCLK /fC) = 50:1
90
PHASE (DEG)
Note 1: Absolute Maximum Ratings are those values beyond which the life of a
device may be impaired.
Note 2: Input frequencies, f, are linearly phase shifted through the filter as long as
f ≤ fC; 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/fC); f ≤ fC.
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 3: Group delay and group delay deviation are calculated from the measured
phase factor and phase deviation specifications.
Note 4: The AC swing is typically 11VP-P, 7VP-P, 2.8VP-P for ± 7.5V, ± 5V, ± 2.5V
supply respectively. For more information refer to the THD + Noise vs Input graphs.
UNITS
µs
µs
µs
µs
%
%
%
%
kHz
kHz
MHz
MHz
MHz
µVRMS
µVRMS
µVRMS
µVRMS
kΩ
V
V
V
mV
mV
µV/°C
µV/°C
mA
mA
mA
mA
mA
mA
V
0
–90
–180
–270
–360
0
1
2
3 4 5 6 7
FREQUENCY (kHz)
8
9
10
1164-7 F01
Figure 1. Phase Response in the Passband (Note 1)
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LTC1164-7
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TYPICAL PERFOR A CE CHARACTERISTICS
Phase Factor vs fCLK
(Typical Unit)
Gain vs Frequency
Phase Factor vs fCLK
(Typical Unit)
438
10
436
VS = ±5V
(fCLK /fC) = 50:1
0
–10
434
100:1
–40
50:1
–50
–60
–70
–80
437
70°C
25°C
0°C
436
432
–100
–110
0.1
25°C
431
70°C
430
429
VS = ±5V
fCLK = 500kHz
TA = 25°C
–90
0°C
428
427
1
10
FREQUENCY (kHz)
435
0.25
100
0.75
0.5
426
0.25
1.0
1164-7 G03
Phase Factor vs fCLK (Min and
Max Representative Units)
Gain vs Frequency
10
438
VS = ±5V
(fCLK /fC) = 50:1
TA = 25°C
PHASE FACTOR
437
435
VS = SINGLE 5V
PINS 3, 5 AT 2V
(fCLK /fC) = 50:1
TA = 25°C
0
–10
–20
436
GAIN (dB)
438
435
–30
–40
–50
VS = SINGLE 5V
fCLK = 1MHz
fC = 10kHz
(fCLK /fC) = 50:1
TA = 25°C
–60
434
434
–70
–80
433
0.25
0.75
0.5
1.0
433
0.25
–90
0.75
0.5
fCLK (MHz)
1.0
1164-7 G04
5
90
0
PHASE
–90
VS = ±5V
fCLK = 50kHz
fC = 1kHz
(fCLK /fC) = 50:1
200
800
400
600
FREQUENCY (Hz)
1164-7 G06
1000
1164-7 G07
180
90
GAIN
0
–5
PHASE
–10
–180
–15
–270
–20
–90
VS = ±5V
fCLK = 100kHz
fC = 1kHz
(fCLK /fC) = 100:1
PHASE (DEG)
0
–5
PHASE (DEG)
GAIN (dB)
180
GAIN (dB)
GAIN
–10
100
Passband Gain and Phase
Passband Gain and Phase
–20
10
FREQUENCY (kHz)
1164-7 G05
5
–15
1
fCLK (MHz)
0
1.0
fCLK (MHz)
1164-7 G02
Phase Factor vs fCLK (Min and
Max Representative Units)
436
0.75
0.5
fCLK (MHz)
1264-7 G01
PHASE FACTOR
433
PHASE FACTOR
GAIN (dB)
–30
PHASE FACTOR
–20
437
VS = ±5V
(fCLK /fC) = 100:1
435
–180
–270
200
800
400
600
FREQUENCY (Hz)
1000
1164-7 G08
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LTC1164-7
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TYPICAL PERFOR A CE CHARACTERISTICS
5
VS = ±5V
(fCLK /fC) = 50:1
TA = 25°C
3
A. fCLK = 250kHz
B. fCLK = 500kHz
C. fCLK = 750kHz
D. fCLK = 1000kHz
3
A. fCLK = 250kHz
B. fCLK = 500kHz
C. fCLK = 750kHz
D. fCLK = 1000kHz
2
1
GAIN (dB)
0
–1
–2
B
C D
2
1
0
–1
B
C
D
10
FREQUENCY (kHz)
100
10
FREQUENCY (kHz)
1
100
DELAY (µs)
200
0
–1
B
–3
B
400
350
100
C
D
C D
50
A. fCLK = 250kHz
B. fCLK = 500kHz
C. fCLK = 750kHz
D. fCLK = 1000kHz
300
B
250
200
C
150
D
100
–4
50
0
0
–5
1
10
FREQUENCY (kHz)
2
100
4
6
8 10 12 14 16 18 20
FREQUENCY (kHz)
1164-7 G12
1
22
THD + Noise vs Frequency
THD + Noise vs Frequency
– 55
– 60
– 50
–65
– 70
–75
– 55
– 60
– 50
–65
– 70
–75
– 55
– 60
–65
–75
–85
–85
–85
–90
–90
–90
10
1164-7 G15
11
– 70
–80
5
FREQUENCY (kHz)
10
VS = ±7.5V
VIN = 2VRMS
fCLK = 500kHz
(fCLK /fC) = 100:1
(5 REPRESENTATIVE UNITS)
–45
–80
1
9
THD + Noise vs Frequency
VS = ±5V
VIN = 1VRMS
fCLK = 500kHz
(fCLK /fC) = 50:1
(5 REPRESENTATIVE UNITS)
–45
THD + NOISE (dB)
– 50
4 5
6 7 8
FREQUENCY (kHz)
– 40
THD + NOISE (dB)
VS = ±7.5V
VIN = 2VRMS
fCLK = 500kHz
(fCLK /fC) = 50:1
(5 REPRESENTATIVE UNITS)
3
1264-7 G14
– 40
–45
2
1264-7 G13
– 40
THD + NOISE (dB)
VS = ±5V
(fCLK /fC) = 100:1
TA = 25°C
A
450
A. fCLK = 250kHz
B. fCLK = 500kHz
C. fCLK = 750kHz
D. fCLK = 1000kHz
150
–2
A
VS = ±5V
(fCLK /fC) = 50:1
TA = 25°C
A
A. fCLK = 250kHz
B. fCLK = 500kHz
C. fCLK = 750kHz
D. fCLK = 1000kHz
1
100
Delay vs Frequency and fCLK
500
250
2
10
FREQUENCY (kHz)
1164-7 G11
Delay vs Frequency and fCLK
5
3
B C D
1164-7 G10
Passband Gain vs Frequency
and fCLK
VS = SINGLE 5V
(fCLK /fC) = 50:1
TA = 85°C
A
–5
1
1164-7 G09
4
0
–1
–4
–5
1
1
–3
–4
–5
A. fCLK = 250kHz
B. fCLK = 500kHz
C. fCLK = 750kHz
D. fCLK = 1000kHz
–2
A
–3
–4
GAIN (dB)
3
–2
A
–3
VS = ±5V
(fCLK /fC) = 100:1
TA = 25°C
4
DELAY (µs)
GAIN (dB)
2
5
VS = ±5V
(fCLK /fC) = 50:1
TA = 85°C
4
GAIN (dB)
5
4
Passband Gain vs Frequency
and fCLK
Passband Gain vs Frequency
and fCLK
Passband Gain vs Frequency
and fCLK
–80
1
5
FREQUENCY (kHz)
10
1164-7 G16
1
2
3
FREQUENCY (kHz)
4
5
1164-7 G17
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LTC1164-7
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TYPICAL PERFOR A CE CHARACTERISTICS
THD + Noise vs Frequency
– 55
– 60
VS = SINGLE 5V
VIN = 0.5VRMS
fCLK = 500kHz
(fCLK /fC) = 50:1
AGND = 2V
(5 REPRESENTATIVE UNITS)
–45
– 50
THD + NOISE (dB)
– 50
– 40
–65
– 70
–75
– 55
– 60
–65
– 50
– 70
–75
–65
– 70
–75
–80
–85
–85
–85
–90
1
2
3
FREQUENCY (kHz)
4
1
5
5
FREQUENCY (kHz)
–90
10
THD + Noise vs Frequency
THD + Noise vs Input
VS = SINGLE 5V
VIN = 0.5VRMS
fCLK = 500kHz
(fCLK /fC) = 100:1
AGND = 2.5V
(5 REPRESENTATIVE UNITS)
THD + Noise vs Input
–50
–65
–70
–75
–40
A. VS = ±5V
B. VS = ±7.5V
–50
A
B
–55
–60
–65
–70
–75
–55
–70
–75
–80
–85
–85
–85
2
3
FREQUENCY (kHz)
4
–90
0.1
5
1
A
–65
–70
–75
–80
PHASE DIFFERENCE BETWEEN
ANY TWO UNITS (SAMPLE OF
50 REPRESENTATIVE UNITS)
VS ≥ ±5V
fCLK ≤ 500kHz
(fCLK /fC) = 50:1 OR 100:1
TA = 0°C TO 70°C
4
3
11
9
2
8
25°C
7
125°C
6
5
4
3
1
2
A. AGND = 2V
B. AGND = 2.5V
–90
0.1
–55°C
10
CURRENT (mA)
B
–60
–85
12
5
PHASE DIFFERENCE (DEG)
–55
Power Supply Current vs
Power Supply Voltage
Phase Matching vs Frequency
–40
–50
1164-7 G23
1164-7 G22
THD + Noise vs Input
VS = SINGLE 5V
fCLK = 500kHz
fIN = 1kHz
(fCLK /fC) = 100:1
2
1
INPUT (VRMS)
INPUT (VRMS)
1164-7 G21
–45
A. AGND = 2V
B. AGND = 2.5V
–90
0.1
5
A
–65
–80
1
B
–60
–80
–90
VS = SINGLE 5V
fCLK = 500kHz
fIN = 1kHz
(fCLK /fC) = 50:1
–45
THD + NOISE (dB)
– 55
– 60
fIN = 1kHz
fCLK = 500kHz
(fCLK /fC) = 50:1
–45
THD + NOISE (dB)
– 50
10
1164-7 G20
–40
–45
5
FREQUENCY (kHz)
1
1164-7 G19
– 40
THD + NOISE (dB)
– 60
–80
1164-7 G18
THD + NOISE (dB)
– 55
–80
–90
VS = SINGLE 5V
VIN = 0.5VRMS
fCLK = 500kHz
(fCLK /fC)= 50:1
AGND = 2.5V
(5 REPRESENTATIVE UNITS)
–45
THD + NOISE (dB)
VS = ±5V
VIN = 1VRMS
fCLK = 500kHz
(fCLK /fC) = 100:1
(5 REPRESENTATIVE UNITS)
–45
THD + NOISE (dB)
THD + Noise vs Frequency
THD + Noise vs Frequency
– 40
– 40
1
1
2
INPUT (VRMS)
1164-7 G24
0
0
0
0.2
0.6
0.8
0.4
FREQUENCY (fCUTOFF /FREQUENCY)
1.0
1164-7 G25
0
1
3 4
2
5 6 7 8
POWER SUPPLY (V + OR V –)
9
10
1164-7 G26
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LTC1164-7
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TYPICAL PERFOR A CE CHARACTERISTICS
Table 1. Passband Gain and Phase
VS = ±7.5V, Ratio = 50:1, TA = 25°C
FREQUENCY (kHz)
fCLK = 250kHz (Typical Unit)
0.000
1.250
2.500
3.750
5.000
GAIN (dB)
Table 2. Passband Gain and Phase
VS = ±7.5V, Ratio = 100:1, TA = 25°C
PHASE (DEG)
– 0.085
– 0.085
– 0.261
– 1.092
– 3.647
180.00
71.51
– 37.31
– 146.38
– 255.45
FREQUENCY (kHz)
fCLK = 250kHz (Typical Unit)
0.000
0.625
1.250
1.875
2.500
fCLK = 500kHz (Typical Unit)
0.000
2.500
5.000
7.500
10.000
– 0.091
– 0.091
– 0.251
– 1.028
– 3.488
180.00
71.36
– 37.57
–146.78
– 256.16
fCLK = 750kHz (Typical Unit)
0.000
3.750
7.500
11.250
15.000
– 0.106
– 0.106
– 0.264
– 0.943
– 3.206
fCLK = 1MHz (Typical Unit)
0.000
5.000
10.000
15.000
20.000
– 0.131
– 0.131
– 0.291
– 0.853
– 2.864
fCLK = 500kHz (Typical Unit)
0.000
2.500
5.000
7.500
10.000
GAIN (dB)
PHASE (DEG)
– 0.201
– 0.201
– 0.727
– 2.075
– 5.205
180.00
71.39
– 36.79
– 143.66
– 247.79
fCLK = 500kHz (Typical Unit)
0.000
1.250
2.500
3.750
5.000
– 0.176
– 0.176
– 0.645
– 1.945
– 5.032
180.00
71.34
– 36.88
– 143.93
– 248.52
180.00
71.26
– 37.65
– 146.88
– 256.58
fCLK = 750kHz (Typical Unit)
0.000
1.875
3.750
5.625
7.500
– 0.161
– 0.161
– 0.574
– 1.789
– 4.779
180.00
71.32
– 37.04
– 144.45
– 249.82
180.00
71.11
– 37.71
– 146.87
– 256.81
fCLK = 1MHz (Typical Unit)
0.000
2.500
5.000
7.500
10.000
– 0.157
– 0.157
– 0.538
– 1.666
– 4.527
180.00
71.23
– 37.28
– 145.02
– 251.13
Table 3. Passband Gain and Phase
VS = ±5V, Ratio = 50:1, TA = 25°C
FREQUENCY (kHz)
fCLK = 250kHz (Typical Unit)
0.000
1.250
2.500
3.750
5.000
GAIN (dB)
Table 4. Passband Gain and Phase
VS = ±5V, Ratio = 100:1, TA = 25°C
PHASE (DEG)
– 0.071
– 0.071
– 0.243
– 1.068
– 3.609
180.00
71.48
– 37.29
– 146.34
– 255.40
FREQUENCY (kHz)
fCLK = 250kHz (Typical Unit)
0.000
0.625
1.250
1.875
2.500
– 0.081
– 0.081
– 0.236
– 0.981
– 3.371
180.00
71.35
– 37.52
–146.71
– 256.13
GAIN (dB)
PHASE (DEG)
– 0.189
– 0.189
– 0.707
– 2.048
– 5.711
180.00
71.39
– 36.75
– 143.60
– 247.74
fCLK = 500kHz (Typical Unit)
0.000
1.250
2.500
3.750
5.000
– 0.159
– 0.159
– 0.603
– 1.872
– 4.926
180.00
71.35
– 36.85
– 144.00
– 248.80
– 0.149
– 0.149
– 0.536
– 1.704
– 4.621
180.00
71.28
– 37.13
– 144.72
– 250.48
– 0.151
– 0.151
– 0.511
– 1.581
– 4.336
180.00
71.10
– 37.52
– 145.45
– 252.01
fCLK = 750kHz (Typical Unit)
0.000
3.750
7.500
11.250
15.000
– 0.105
– 0.105
– 0.261
– 0.883
– 3.008
180.00
71.26
– 37.62
– 146.80
– 256.57
fCLK = 750kHz (Typical Unit)
0.000
1.875
3.750
5.625
7.500
fCLK = 1MHz (Typical Unit)
0.000
5.000
10.000
15.000
20.000
– 0.134
– 0.134
– 0.292
– 0.771
– 2.571
180.00
70.99
– 37.75
– 146.83
– 256.88
fCLK = 1MHz (Typical Unit)
0.000
2.500
5.000
7.500
10.000
11647fb
7
LTC1164-7
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Table 5. Passband Gain and Phase
VS = Single 5V, Ratio = 50:1, TA = 25°C
FREQUENCY (kHz)
fCLK = 250kHz (Typical Unit)
0.000
1.250
2.500
3.750
5.000
fCLK = 500kHz (Typical Unit)
0.000
2.500
5.000
7.500
10.000
fCLK = 750kHz (Typical Unit)
0.000
3.750
7.500
11.250
15.000
fCLK = 1MHz (Typical Unit)
0.000
5.000
10.000
15.000
20.000
GAIN (dB)
Table 6. Passband Gain and Phase
VS = Single 5V, Ratio = 100:1, TA = 25°C
– 0.085
– 0.085
– 0.252
– 1.056
– 3.562
180.00
71.54
– 37.15
– 146.12
– 255.22
FREQUENCY (kHz)
fCLK = 250kHz (Typical Unit)
0.000
0.625
1.250
1.875
2.500
– 0.101
– 0.101
– 0.251
– 0.947
– 3.252
180.00
71.39
– 37.38
–146.44
– 256.02
– 0.133
– 0.133
– 0.291
– 0.826
– 2.789
– 0.162
– 0.162
– 0.307
– 0.647
– 2.201
PHASE (DEG)
GAIN (dB)
PHASE (DEG)
– 0.283
– 0.283
– 0.799
– 2.143
– 5.271
180.00
71.35
– 37.01
– 143.96
– 248.03
fCLK = 500kHz (Typical Unit)
0.000
1.250
2.500
3.750
5.000
– 0.252
– 0.252
– 0.676
– 1.917
– 4.936
180.00
71.28
– 37.16
– 144.46
– 249.40
180.00
71.16
– 37.56
– 146.55
– 256.52
fCLK = 750kHz (Typical Unit)
0.000
1.875
3.750
5.625
7.500
– 0.231
– 0.231
– 0.603
– 1.704
– 4.535
180.00
70.94
– 37.72
– 145.55
– 251.81
180.00
70.89
– 37.78
– 146.67
– 257.06
fCLK = 1MHz (Typical Unit)
0.000
2.500
5.000
7.500
10.000
– 0.212
– 0.212
– 0.532
– 1.497
– 4.115
180.00
70.83
– 38.11
– 146.47
– 253.92
11647fb
8
LTC1164-7
U
U
U
PI FU CTIO S
NC (Pins 1, 8, 13): Pins 1, 8 and 13 are not connected to
any internal circuit point on the device and should be
preferably tied to analog ground.
Filter Input (Pin 2): The input pin is connected internally
through a 50k resistor tied to the inverting input of an op
amp.
Analog GND (Pins 3, 5): The filter performance depends
on the quality of the analog signal ground. For either dual
or single supply operation, an analog ground plane surrounding the package is recommended. The analog ground
plane should be connected to any digital ground at a single
point. For dual supply operation, Pins 3 and 5 should be
connected to the analog ground plane. For single supply
operation, Pins 3 and 5 should be biased at 1/2 supply and
should be bypassed to the analog ground plane with at
least a 1µF capacitor (Figure 3). For single 5V operation at
the highest fCLK of 2MHz, Pins 3 and 5 should be biased at
2V. This minimizes passband gain and phase variations.
Power Supply (Pins 4, 12): The V + (pin 4) and the V – (Pin
12) should each be bypassed with a 0.1µF capacitor to an
adequate analog ground. The filter’s power supplies should
be isolated from other digital or high voltage analog
supplies. A low noise linear supply is recommended.
Using a switching power supply will lower the signal-tonoise ratio of the filter. The supply during power-up should
have a slew rate less than 1V/µs. When V + is applied before
V – and V – is allowed to go above ground, a signal diode
should clamp V – to prevent latch-up. Figures 2 and 3 show
typical connections for dual and single supply operation.
Filter Output (Pins 6, 9): Pin 6 is an intermediate filter
output providing an unspecified 6th order lowpass filter.
Pin 6 should not be loaded. Pin 9 is the specified output of
the filter; it can typically source/sink 1mA. Driving coaxial
cables or resistive loads less than 20k will degrade the
total harmonic distortion of the filter. When evaluating the
device’s distortion an output buffer is required. A
noninverting buffer, Figure 4, can be used provided that its
input common-mode range is well within the filter’s output
swing.
External Connection (Pins 7, 14): Pins 7 and 14 should be
connected together. In a printed circuit board the connection should be done under the IC package through a short
trace surrounded by the analog ground plane.
Ratio Input (Pin 10): The DC level at this pin determines
the ratio of the clock frequency to the cutoff frequency of
the filter. Pin 10 at V + gives a 50:1 ratio and pin 10 at V –
gives a 100:1 ratio. For single supply operation the ratio is
50:1 when Pin 10 is at V + and 100:1 when Pin 10 is at
ground. When Pin 10 is not tied to ground, it should be
bypassed to analog ground with a 0.1µF capacitor. If the
DC level at Pin 10 is switched mechanically or electrically
at slew rates greater than 1V/µs while the device is
operating, a 10k resistor should be connected between pin
10 and the DC source.
Clock Input (Pin 11): Any TTL or CMOS clock source with
a square-wave output and 50% duty cycle (±10%) is an
adequate clock source for the device. The power supply for
the clock source should not be the filter’s power supply.
The analog ground for the filter should be connected to
clock’s ground at a single point only. Table 7 shows the
clock’s low and high level threshold values for dual or
single supply operation. A pulse generator can be used as
a clock source provided the high level ON time is greater
than 0.5µs. Sine waves are not recommended for clock
input frequencies less than 100kHz, since excessively
slow clock rise or fall times generate internal clock jitter
(maximum clock rise or fall time ≤ 1µs). The clock signal
should be routed from the right side of the IC package and
perpendicular to it to avoid coupling to any input or output
analog signal path. A 1k resistor between clock source and
Pin 11 will slow down the rise and fall times of the clock to
further reduce charge coupling (Figures 2 and 3).
Table 7. Clock Source High and Low Threshold Levels
POWER SUPPLY
Dual Supply = ±7.5V
Dual Supply = ±5V
Dual Supply = ± 2.5V
Single Supply = 12V
Single Supply = 5V
HIGH LEVEL
≥ 2.18V
≥ 1.45V
≥ 0.73V
≥ 7.80V
≥ 1.45V
LOW LEVEL
≤ 0.5V
≤ 0.5V
≤ – 2.0V
≤ 6.5V
≤ 0.5V
11647fb
9
LTC1164-7
U
U
U
PI FU CTIO S
V–
VIN
1
14
2
13
3
12
4
V+
0.1µF
LTC1164-7
0.1µF
1k
11
5
10
6
9
7
8
CLOCK SOURCE
V+
+
GND
DIGITAL SUPPLY
VOUT
1164-7 F02
Figure 2. Dual Supply Operation for an fCLK/fCUTOFF = 50:1
VIN
V
14
2
13
3
12
11
1k
5
10
V+
6
9
7
8
4
+
0.1µF
10k
10k
1
LTC1164-7
CLOCK SOURCE
+
GND
DIGITAL SUPPLY
+
1µF
VOUT
1164-7 F03
Figure 3. Single Supply Operation for an fCLK/fCUTOFF = 50:1
–
1k
LT1056
+
1164-7 F04
Figure 4. Buffer for Filter Output
11647fb
10
LTC1164-7
U
W
U
UO
APPLICATI
S I FOR ATIO
Clock Feedthrough
Clock feedthrough is defined as the RMS value of the clock
frequency and its harmonics that are present at the filter’s
output pin (9). The clock feedthrough is tested with the
input pin (2) grounded and it depends on PC board layout
and on the value of the power supplies. With proper layout
techniques the values of the clock feedthrough are shown
in Table 8.
Table 8. Clock Feedthrough
VS
Single 5V
±5V
±7.5V
50:1
70µVRMS
100µVRMS
120µVRMS
100:1
70µVRMS
200µVRMS
500µVRMS
Note: The clock feedthrough at Single 5V is imbedded in the wideband
noise of the filter. The clock waveform is a square wave.
Any parasitic switching transients during the rise and fall
edges of the incoming clock are not part of the clock
feedthrough specifications. Switching transients have frequency contents much higher than the applied clock; their
amplitude strongly depends on scope probing techniques
as well as grounding and power supply bypassing. The
clock feedthrough, if bothersome, can be greatly reduced
by adding a simple R/C lowpass network at the output of
the filter pin (9). This R/C will completely eliminate any
switching transients.
Wideband Noise
The wideband noise of the filter is the total RMS value of
the device’s noise spectral density and it is used to
determine the operating signal-to-noise ratio. Most of its
frequency contents lie within the filter’s passband and
cannot be reduced with post filtering. For instance, the
LTC1164-7 wideband noise at ±5V supply is 105µVRMS,
95µVRMS of which have frequency contents from DC up to
the filter’s cutoff frequency. The total wideband noise
(µVRMS) is nearly independent of the value of the clock.
The clock feedthrough specifications are not part of the
wideband noise.
Speed Limitations
The LT1164-7 optimizes AC performance vs power consumption. To avoid op amp slew rate limiting at maximum
clock frequencies, the signal amplitude should be kept
below a specified level as shown in Table 9.
Table 9. Maximum VIN vs VS and Clock
POWER SUPPLY
±7.5V
MAXIMUM fCLK
1MHz
±5V
1MHz
Single 5V
1MHz
MAXIMUM VIN
2.0VRMS (fIN > 20kHz)
0.7VRMS (fIN > 250kHz)
1.4VRMS (fIN > 20kHz)
0.5VRMS (fIN > 100kHz)
0.5VRMS (fIN > 100kHz)
Table 10. Transient Response of LTC Lowpass Filters
LOWPASS FILTER
LTC1064-3 Bessel
LTC1164-5 Bessel
LTC1164-6 Bessel
DELAY
TIME*
(SEC)
0.50/fC
0.43/fC
0.43/fC
RISE SETTLING OVERTIME** TIME*** SHOOT
(SEC)
(SEC)
(%)
0.34/fC
0.80/fC
0.5
0.34/fC
0.85/fC
0
0.34/fC
1.15/fC
1
LTC1264-7 Linear Phase
LTC1164-7 Linear Phase
LTC1064-7 Linear Phase
1.15/fC
1.20/fC
1.20/fC
0.36/fC
0.39/fC
0.39/fC
2.05/fC
2.20/fC
2.20/fC
5
5
5
LTC1164-5 Butterworth
0.80/fC
0.48/fC
2.40/fC
11
LTC1164-6 Elliptic
LTC1064-4 Elliptic
LTC1064-1 Elliptic
0.85/fC
0.90/fC
0.85/fC
0.54/fC
0.54/fC
0.54/fC
4.30/fC
4.50/fC
6.50/fC
18
20
20
* To 50% ±5%, ** 10% to 90% ±5%, *** To 1% ±0.5%
11647fb
11
LTC1164-7
U
W
U
UO
APPLICATI
S I FOR ATIO
Transient Response
2V/DIV
If, for instance, an LTC1164-7 operating with a 100kHz
clock and 1kHz cutoff frequency receives a 98kHz 10mV
input signal, a 2kHz, 143µVRMS alias signal will appear at
its output. When the LTC1164-7 operates with a clock-tocutoff frequency of 50:1, aliasing occurs at twice the clock
frequency. Table 11 shows details.
Table 11. Aliasing (fCLK = 100kHz)
100µs/DIV
INPUT = 1kHz ± 3V
fCLK = 500kHz
fC = 10kHz
VS = ±7.5V
ts
OUTPUT
90%
50%
10%
OUTPUT LEVEL
(Relative to Input,
0dB = 1VRMS)
(dB)
OUTPUT FREQUENCY
(Aliased Frequency
fOUT = ABS [fCLK ± fIN])
(kHz)
190 (or 210)
195 (or 205)
196 (or 204)
197(or 203)
198 (or 202)
199.5 (or 200.5)
100:1, fCUTOFF = 1kHz
–76.1
– 51.9
– 36.3
– 18.4
– 3.0
– 0.2
10.0
5.0
4.0
3.0
2.0
0.5
97 (or 103)
97.5 (or 102.5)
98 (or 102)
98.5 (or 101.5)
99 (or 101)
99.5 (or 100.5)
–74.2
– 53.2
– 36.9
– 19.6
– 5.2
– 0.7
3.0
2.5
2.0
1.5
1.0
0.5
1164-7 F05
Figure 5
INPUT
INPUT FREQUENCY
(VIN = 1VRMS,
fIN = fCLK ± fOUT)
(kHz)
50:1, fCUTOFF = 2kHz
td
tr
0.39
±5%
fCUTOFF
2.2
SETTLING TIME (ts) =
±5%
f
(TO 1% of OUTPUT) CUTOFF
1.2
TIME DELAY (td) = GROUP DELAY ≈
fCUTOFF
(TO 50% OF OUTPUT)
1V/DIV
RISE TIME (tr) =
1164-7 F06
Figure 6
Aliasing
5µs/DIV
Aliasing is an inherent phenomenon of sampled data
systems and it occurs when input frequencies close to the
sampling frequency are applied. For the LTC1164-7 case
at 100:1, an input signal whose frequency is in the range
of fCLK ±3%, will be aliased back into the filter’s passband.
1164-7 F07
VS = ±7.5V
fCLK = 1MHz
fC = 20kHz
(fCLK /fC) = 50:1
Figure 7. Eye Diagram
11647fb
12
LTC1164-7
U
PACKAGE DESCRIPTIO
J Package
14-Lead CERDIP (Narrow .300 Inch, Hermetic)
(Reference LTC DWG # 05-08-1110)
.005
(0.127)
MIN
.785
(19.939)
MAX
14
13
12
11
10
9
8
.220 – .310
(5.588 – 7.874)
.025
(0.635)
RAD TYP
1
2
3
4
5
6
7
.300 BSC
(7.62 BSC)
.200
(5.080)
MAX
.015 – .060
(0.381 – 1.524)
.008 – .018
(0.203 – 0.457)
0° – 15°
.045 – .065
(1.143 – 1.651)
NOTE: LEAD DIMENSIONS APPLY TO SOLDER DIP/PLATE
OR TIN PLATE LEADS
.014 – .026
(0.360 – 0.660)
.100
(2.54)
BSC
.125
(3.175)
MIN
J14 0801
OBSOLETE PACKAGE
11647fb
13
LTC1164-7
U
PACKAGE DESCRIPTIO
N Package
14-Lead PDIP (Narrow .300 Inch)
(Reference LTC DWG # 05-08-1510)
.770*
(19.558)
MAX
14
13
12
11
10
9
8
1
2
3
4
5
6
7
.255 ± .015*
(6.477 ± 0.381)
.130 ± .005
(3.302 ± 0.127)
.300 – .325
(7.620 – 8.255)
.045 – .065
(1.143 – 1.651)
.020
(0.508)
MIN
.065
(1.651)
TYP
.008 – .015
(0.203 – 0.381)
(
+.035
.325 –.015
+0.889
8.255
–0.381
NOTE:
1. DIMENSIONS ARE
)
.120
(3.048)
MIN
.005
(0.127) .100
MIN (2.54)
BSC
.018 ± .003
(0.457 ± 0.076)
N14 1103
INCHES
MILLIMETERS
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .010 INCH (0.254mm)
11647fb
14
LTC1164-7
U
PACKAGE DESCRIPTIO
SW Package
16-Lead Plastic Small Outline (Wide .300 Inch)
(Reference LTC DWG # 05-08-1620)
.050 BSC .045 ±.005
.030 ±.005
TYP
.398 – .413
(10.109 – 10.490)
NOTE 4
16
N
15
14
13
12
11 10
9
N
.325 ±.005
.420
MIN
.394 – .419
(10.007 – 10.643)
NOTE 3
1
2
3
N/2
N/2
RECOMMENDED SOLDER PAD LAYOUT
1
.005
(0.127)
RAD MIN
.009 – .013
(0.229 – 0.330)
.291 – .299
(7.391 – 7.595)
NOTE 4
.010 – .029 × 45°
(0.254 – 0.737)
3
4
5
6
7
.093 – .104
(2.362 – 2.642)
8
.037 – .045
(0.940 – 1.143)
0° – 8° TYP
NOTE 3
.016 – .050
(0.406 – 1.270)
NOTE:
1. DIMENSIONS IN
2
.050
(1.270)
BSC
.004 – .012
(0.102 – 0.305)
.014 – .019
(0.356 – 0.482)
TYP
INCHES
(MILLIMETERS)
2. DRAWING NOT TO SCALE
3. PIN 1 IDENT, NOTCH ON TOP AND CAVITIES ON THE BOTTOM OF PACKAGES ARE THE MANUFACTURING OPTIONS.
THE PART MAY BE SUPPLIED WITH OR WITHOUT ANY OF THE OPTIONS
4. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm)
S16 (WIDE) 0502
11647fb
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 representation that
the interconnection of its circuits as described herein will not infringe on existing patent rights.
15
LTC1164-7
U
TYPICAL APPLICATIO S
–5V
VIN
1
14
2
13
3
12
4
+5V
0.1µF
LTC1164-7
1N4148
0.1µF
1k
11
5
10
6
9
7
8
1MHz CLOCK
+5V
+
GND
DIGITAL SUPPLY
VOUT
1164-7 TA03
20kHz Linear Phase Lowpass Filter
Eye Diagram
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LTC1064
Universal Filter Building Block
Allows for Bandpass (Up to 50kHz) Using Ext Resistors
LTC1064-1/2/3/4/7
8th Order Low Pass Filters, FO Max = 100kHz
Cauer, Butterworth, Bessel or Improved Bessel
LTC1164
Universal Filter Building Block
Allows for Bandpass (Up to 20kHz) Using Ext Resistors
LTC1164-5/6
8th Order Low Pass Filters, FO Max = 20kHz
Butterworth, Bessel or Elliptic
LTC1264
Universal Filter Building Block
Allows for Bandpass (Up to 100kHz) Using Ext Resistors
LTC1264-7
8th Order Low Pass Filter, FO Max = 200kHz
Flat Group Delay, High Speed Lowpass Filter
LT6600-2.5
Low Noise Differential Amp and 10MHz Lowpass
55µVRMS Noise 100kHz to 10MHz 3V Supply
LT6600-10
Low Noise Differential Amp and 20MHz Lowpass
86µVRMS Noise 100kHz to 20MHz 3V Supply
11647fb
16
Linear Technology Corporation
LT/LT 0905 REV B • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507
●
www.linear.com
© LINEAR TECHNOLOGY CORPORATION 1992