1
LTC1164-6
11646fa
Low Power 8th Order
Pin Selectable Elliptic or
Linear Phase Lowpass Filter
■
8th Order Pin Selectable Elliptic or Bessel Filter
■
4mA Supply Current with ±5V Supplies
■
64dB Attenuation at 1.44 f
CUTOFF
(Elliptic Response)
■
f
CUTOFF
Up to 30kHz (50:1 f
CLK
to f
CUTOFF
Ratio)
■
110µV
RMS
Wideband Noise with ±5V Supplies
■
Operates at Single 5V Supply with 1V
RMS
Input Range
■
Operates Up to ±8V Supplies
■
TTL/CMOS Compatible Clock Input
■
No External Components
■
Available in 14-Pin Dip and 16-Pin SO Wide Packages
■
Antialiasing Filters
■
Battery-Operated Instruments
■
Telecommunication Filters
The LTC
®
1164-6 is a monolithic 8th order elliptic lowpass
filter featuring clock-tunable cutoff frequency and low
power supply current. Low power operation is achieved
without compromising noise or distortion performance.
At ±5V supplies the LTC1164-6 uses only 4mA supply
current while keeping wideband noise below 110µV
RMS
.
With a single 5V supply, the LTC1164-6 can provide up to
10kHz cutoff frequency and 80dB signal-to-noise ratio
while consuming only 2.5mA.
The LTC1164-6 provides an elliptic lowpass rolloff with
stopband attenuation of 64dB at 1.44 f
CUTOFF
and an f
CLK
-
to-f
CUTOFF
ratio of 100:1 (Pin 10 to V
–
). For a ratio of 100:1,
f
CUTOFF
can be clock-tuned up to 10kHz. For a f
CLK
-to-
f
CUTOFF
ratio of 50:1 (Pin 10 to V
+
), the LTC1164-6
provides an elliptic lowpass filter with f
CUTOFF
frequencies
up to 20kHz. When Pin 10 is connected to ground, the
LTC1164-6 approximates an 8th order linear phase re-
sponse with 65dB attenuation at 4.5 f
–3dB
and f
CLK
/f
–3dB
ratio of 160:1. The LTC1164-6 is pin compatible with the
LTC1064-1.
10kHz Anti-Aliasing Elliptic Filter Frequency Response
DESCRIPTIO
U
FEATURES
APPLICATIO S
U
TYPICAL APPLICATIO
U
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
1
2
3
4
5
6
7
14
13
12
11
10
9
8
LTC1164-6
V
IN
8V
–8V
CLK = 1MHz
V
OUT
WIDEBAND NOISE = 115µV
RMS
NOTE: THE CONNECTION FROM PIN 7 TO PIN 14 SHOULD BE MADE
UNDER THE PACKAGE. THE POWER SUPPLIES SHOULD BE BYPASSED
BY A 0.1µF CAPACITOR AS CLOSE TO THE PACKAGE AS POSSIBLE.
1164-6 TA01
NC
NC
–8V
FREQUENCY (kHz)
1
GAIN (dB)
0
–10
–20
–30
–40
–50
–60
–70
–80
10 100
1164-6 TA02
2
LTC1164-6
11646fa
A
U
G
W
A
W
U
W
ARBSOLUTEXI T
IS
Total Supply Voltage (V
+
to V
–
) ............................. 16V
Input Voltage (Note 2) ......... (V
+
+ 0.3V) to (V
–
– 0.3V)
Output Short-Circuit Duration ......................... Indefinite
Power Dissipation............................................. 400mW
Burn-In Voltage ...................................................... 16V
Operating Temperature Range
LTC1164-6C ...................................... – 40°C to 85°C
LTC1164-6M (OBSOLETE) .............. – 55°C to 125°C
Storage Temperature Range ................ – 65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
(Note 1)
WU
U
PACKAGE/ORDER I FOR ATIO
1
2
3
4
5
6
7
TOP VIEW
N PACKAGE
14-LEAD PDIP
14
13
12
11
10
9
8
NC
V
IN
GND
V
+
GND
LP6
CONNECT 1
CONNECT 2
NC
V
–
CLK
ELL/BESS
V
OUT
NC
LTC1164-6CN
TJMAX = 110°C, θJA = 85°C/W
J PACKAGE 14-LEAD CERDIP
TJMAX = 150°C, θJA = 65°C/W
ORDER PART
NUMBER
ORDER PART
NUMBER
LTC1164-6CSW
TOP VIEW
SW PACKAGE
16-LEAD PLASTIC SO
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
CLK
ELL/BESS
NC
V
OUT
TJMAX = 110°C, θJA = 65°C/W
LTC1164-6CJ
LTC1164-6MJ
OBSOLETE PACKAGE
Consider the N14 Package as an Alternate Source
ELECTRICAL C CHARA TERISTICS
PARAMETER CONDITIONS MIN TYP MAX UNITS
Passband Gain 0.1Hz to 0.25 f
CUTOFF
(Note 4) f
IN
= 1kHz, (f
CLK
/f
C
) = 100:1 ●–0.50 – 0.15 0.25 dB
Passband Ripple with V
S
= Single 5V 1Hz to 0.8 f
C
(Table 2) 0.1 to – 0.3 dB
Gain at 0.50 f
CUTOFF
(Note 3) f
IN
= 2kHz, (f
CLK
/f
C
) = 100:1 ●–0.45 –0.10 0.10 dB
Gain at 0.90 f
CUTOFF
(Note 3) f
IN
= 3.6kHz, (f
CLK
/f
C
) = 100:1 ●–0.75 – 0.30 0.10 dB
Gain at 0.95 f
CUTOFF
(Note 3) f
IN
= 3.8kHz, (f
CLK
/f
C
) = 100:1 ●–1.40 – 0.70 – 0.40 dB
Gain at f
CUTOFF
(Note 3) f
IN
= 4kHz, (f
CLK
/f
C
) = 100:1 ●–3.70 –2.70 –2.30 dB
f
IN
= 8kHz, (f
CLK
/f
C
) = 50:1 ●–3.10 – 2.10 – 1.50 dB
Gain at 1.44 f
CUTOFF
(Note 3) f
IN
= 5.76kHz, (f
CLK
/f
C
) = 100:1 ●–75 –64 –58 dB
Gain at 2.0 f
CUTOFF
(Note 3) f
IN
= 8kHz, (f
CLK
/f
C
) = 100:1 ●–75 –64 –58 dB
Gain with f
CLK
= 20kHz f
IN
= 200Hz, (f
CLK
/f
C
) = 100:1 –3.70 – 2.70 – 2.30 dB
Gain with V
S
= ±2.375V f
IN
= 400kHz, f
IN
= 2kHz, (f
CLK
/f
C
) = 100:1 –0.50 – 0.10 0.30 dB
f
IN
= 400kHz, f
IN
= 4kHz, (f
CLK
/f
C
) = 100:1 –3.50 – 2.50 – 2.00 dB
Input Frequency Range (Tables 3, 4) (f
CLK
/f
C
) = 100:1 0 – <f
CLK
/2 kHz
(f
CLK
/f
C
) = 50:1 0 – <f
CLK
kHz
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 specifications that apply over the full operating temperature
range, otherwise specifications are at TA = 25°C. VS = ±7.5V, RL = 10k, TA = 25°C, fCLK = 400kHz, TTL or CMOS level (maximum clock
rise or fall time ≤ 1µs) and all gain measurements are referenced to passband gain, unless otherwise specified. (fCLK /fCUTOFF) = 4kHz
at 100:1 and 8kHz at 50:1.
3
LTC1164-6
11646fa
PARAMETER CONDITIONS MIN TYP MAX UNITS
Maximum f
CLK
(Table 3) V
S
≥ ±7.5V 1.5 MHz
V
S
≤ ±5V 1.0 MHz
V
S
= Single 5V, AGND = 2V 1.0 MHz
Clock Feedthrough Input at GND, f = f
CLK
, Square Wave
V
S
= ±7.5V, (f
CLK
/f
C
) = 100:1 500 µV
RMS
V
S
=
±5V, (f
CLK
/f
C
) = 50:1 200 µV
RMS
Wideband Noise Input at GND, 1Hz ≤ f < f
CLK
V
S
= ±7.5V 115 ± 5% µV
RMS
V
S
= ±2.5V 100 ± 5% µV
RMS
Input Impedance 45 75 110 kΩ
Output DC Voltage Swing V
S
= ±2.375V ●±1.25 ±1.50 V
V
S
= ±5V ●±3.70 ±4.10 V
V
S
= ±7.5V ●±5.40 ±5.90 V
Output DC Offset V
S
= ±5V, (f
CLK
/f
C
) = 100:1 ±100 ±160 mV
Output DC Offset Tempco V
S
= ±5V, (f
CLK
/f
C
) = 100:1 ±100 µV/°C
Power Supply Current V
S
= ±2.375V, T
A
> 25°C 2.5 4.0 mA
● 4.5 mA
V
S
= ±5V, T
A
> 25°C 4.5 7.0 mA
● 8.0 mA
V
S
= ±7.5V, T
A
> 25°C 7.0 11.0 mA
●12.5 mA
Power Supply Range ±2.375 ±8V
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: Connecting any pin to voltages greater than V
+
or less than V
–
may cause latch-up. It is recommended that no sources operating from
external supplies be applied prior to power-up of the LTC1164-6.
Note 3: All gains are measured relative to passband gain.
Note 4: The cutoff frequency of the filter is abbreviated as f
CUTOFF
or f
C
.
Stopband Gain vs Frequency
(Elliptic Response)
CCHARA TERISTICS
UW
ATYPICALPER
FORCE
Stopband Gain vs Frequency
(Elliptic Response)
FREQUENCY (kHz)
2
GAIN (dB)
10
0
–10
–20
–30
–40
–50
–60
–70
–80
–90 18
1164-6 G02
610 14 22
4812 16 20
V
S
= ±5V
f
CLK
= 250kHz
(f
CLK
/f
C
) = 50:1
(PIN 10 AT V
+
)
T
A
= 25°C
WITH EXTERNAL
SINGLE POLE LOW-
PASS RC FILTER
(f
– 3dB
= 10kHz)
FREQUENCY (kHz)
GAIN (dB)
10
0
–10
–20
–30
–40
–50
–60
–70
–80
–90
1164-6 G01
218
610 14 22
4812 16 20
V
S
= ±5V
f
CLK
= 500kHz
f
C
= 5kHz
(f
CLK
/f
C
) = 100:1
(PIN 10 AT V
–
)
T
A
= 25°C
ELECTRICAL C CHARA TERISTICS
The ● denotes specifications that apply over the full operating temperature
range, otherwise specifications are at TA = 25°C. VS = ±7.5V, RL = 10k, TA = 25°C, fCLK = 400kHz, TTL or CMOS level (maximum clock
rise or fall time ≤ 1µs) and all gain measurements are referenced to passband gain, unless otherwise specified. (fCLK /f
CUTOFF) = 4kHz
at 100:1 and 8kHz at 50:1.
4
LTC1164-6
11646fa
CCHARA TERISTICS
UW
ATYPICALPER
FORCE
Passband Gain vs Frequency
FREQUENCY (kHz)
0.4
GAIN (dB)
1.0 1.6 2.2 2.8
1164-6 G05
3.4
0.8
0.4
0
–0.4
–0.8
–1.2
–1.6
–2.0
–2.4
–2.8
4.0
V
S
= ±5V
f
CLK
= 500kHz
f
C
= 5kHz
(f
CLK
/f
C
) = 100:1
(PIN 10 AT V
–
)
T
A
= 25°C
(10 REPRESENTA-
TIVE UNITS)
Maximum Passband over
Temperature
FREQUENCY (kHz)
1
GAIN (dB)
5
1164-6 G11
34
PHASE (DEG)
3
2
1
0
–1
–2
–3
–4
–5
–6
–7
2
V
S
= ±5V
f
CLK
= 800kHz
f
C
= 5kHz
(f
CLK
/f
C
) = 160:1
(PIN 10 AT GND)
T
A
= 25°C
0
–30
–60
–90
–120
–150
–180
–210
–240
–270
–300
PHASE
GAIN
Passband Gain and Phase vs
Frequency (Linear Phase Response)
Passband Gain and Phase vs
Frequency and fCLK
FREQUENCY (kHz)
GAIN (dB)
3
2
1
0
–1
–2
–3
–4
–5
–6
–7
–8
–9
12
1164-6 G08
345
0
–45
–90
–135
–180
–225
–270
–315
–360
–405
–450
–495
–540
PHASE (DEG)
PHASE
B
B
A
A
V
S
= ±5V
f
CLK
= 250kHz
f
C
= 5kHz
(f
CLK
/f
C
) = 50:1
(PIN 10 AT V
–
)
T
A
= 25°C
A. RESPONSE WITHOUT
EXTERNAL SINGLE
POLE RC FILTER
B. RESPONSE WITH AN
EXTERNAL SINGLE
POLE LOWPASS RC
FILTER (f
– 3dB
AT 10kHz)
Passband vs Frequency and fCLK
INPUT FREQUENCY (kHz)
1
GAIN (dB)
5
1164-6 G06
2.0
1.5
1.0
0.5
0
–0.5
–1.0
–1.5
–2.0
–2.5
–3.0 10
ABCD
V
S
= ±5V
(f
CLK
/f
C
) = 100:1
(PIN 10 AT V
–
)
T
A
= 25°C
A. f
CLK
= 400kHz
f
CUTOFF
= 4kHz
B. f
CLK
= 600kHz
f
CUTOFF
= 6kHz
C. f
CLK
= 800kHz
f
CUTOFF
= 8kHz
D. f
CLK
= 1MHz
f
CUTOFF
= 10kHz
Stopband Gain vs Frequency
(Linear Phase Response)
FREQUENCY (kHz)
2
GAIN (dB)
10
0
–10
–20
–30
–40
–50
–60
–70
–80
–90 34
1164-6 G03
10 18 26 42
614 22 30 38
VS = ±5V
fCLK = 800kHz
fC = 5kHz
(fCLK/fC) = 160:1
(PIN 10 AT GND)
TA = 25°C
A. RESPONSE WITHOUT
EXTERNAL RC FILTER
B. RESPONSE WITH AN
EXTERNAL SINGLE
POLE LOWPASS RC
FILTER (f– 3dB AT 10kHz)
A
B
Passband Gain and Phase
vs Frequency
FREQUENCY (kHz)
1
GAIN (dB)
5
1164-6 G04
34
PHASE (DEG)
2.0
1.5
1.0
0.5
0
–0.5
–1.0
–1.5
–2.0
–2.5
–3.0
2
VS = ±5V
fCLK = 500kHz
fC = 5kHz
(fCLK/fC) = 100:1
(PIN 10 AT V–)
TA = 25°C
0
–45
–90
–135
–180
–225
–270
–315
–360
–405
–450
FREQUENCY (kHz)
1
GAIN (dB)
5
1164-6 G07
0.4
0.2
0
–0.2
–0.4
–0.6
–0.8
–1.0
–1.2
–1.4
–1.6 10
A
B
V
S
= ±5V
f
CLK
= 1MHz
f
C
= 10kHz
(f
CLK
/f
C
) = 100:1
(PIN 10 AT V
–
)
A. T
A
= 125°C
B. T
A
= 85°C
D. T
A
= –40°C
C
5
LTC1164-6
11646fa
CCHARA TERISTICS
UW
ATYPICALPER
FORCE
Group Delay vs Frequency
(Linear Phase Response)
FREQUENCY (kHz)
1
GROUP DELAY (µs)
250
200
150
100
50
0
9
1164-6 G22
35711
246810
f
CLK
= 800kHz
(f
CLK
/f
C
) = 160:1
f
C
= 5kHz
Group Delay vs Frequency
(Elliptic Response)
FREQUENCY (kHz)
1
THD + NOISE (dB)
25
1164-6 G13
–40
–45
–50
–55
–60
–65
–70
–75
–80
–85
–90
34
V
S
= ±5V, V
IN
= 1V
RMS
(20k RESISTOR PIN 14 TO V
–
)
f
CLK
= 500kHz, f
C
= 5kHz
(f
CLK
/f
C
) = 100:1, T
A
= 25°C
(5 REPRESENTATIVE UNITS)
THD + Noise vs Frequency
(Elliptic Response)
THD + Noise vs Frequency
(Elliptic Response)
THD + Noise vs Frequency
(Elliptic Response)
Maximum Passband over
Temperature
FREQUENCY (kHz)
GAIN (dB)
1164-6 G10
2.0
1.5
1.0
0.5
0
–0.5
–1.0
–1.5
–2.0
–2.5
–3.0
V
S
= SINGLE 5V
(f
CLK
/f
C
) = 50:1
GND = 2V WITH
EXTERNAL RC
LOWPASS FILTER
(f
– 3dB
= 40kHz)
218
610 14 22
4812 16 20
T
A
= –40°C
T
A
= 70°C
Passband vs Frequency and fCLK
FREQUENCY (kHz)
1
GAIN (dB)
10
1164-6 G09
2.0
1.5
1.0
0.5
0
–0.5
–1.0
–1.5
–2.0
–2.5
–3.0
V
S
= ±8V
(f
CLK
/f
C
) = 50:1
(PIN 10 AT V
+
)
T
A
= 25°C
30
A. f
CLK
= 250kHz
f
CUTOFF
= 5kHz
B. f
CLK
= 500kHz
f
CUTOFF
= 10kHz
C. f
CLK
= 1MHz
f
CUTOFF
= 20kHz
AC
B
FREQUENCY (kHz)
1
THD + NOISE (dB)
25
1164-6 G23
–40
–45
–50
–55
–60
–65
–70
–75
–80
–85
–90
34
V
S
= ±5V
V
IN
= 1V
RMS
f
CLK
= 800kHz
f
C
= 5kHz
(f
CLK
/f
C
) = 160:1
T
A
= 25°C
THD + Noise vs Frequency
(Linear Phase Response)
FREQUENCY (kHz)
THD + NOISE (dB)
1164-6 G16
–40
–45
–50
–55
–60
–65
–70
–75
–80
–85
–90
0.5 15
V
S
= SINGLE 5V, V
IN
= 0.7V
RMS
f
CLK
= 500kHz, f
C
= 5kHz,
(f
CLK
/f
C
) = 100:1, T
A
= 25°C
(5 REPRESENTATIVE UNITS)
FREQUENCY (kHz)
1
GROUP DELAY (µs)
5
1164-6 G12
34
700
600
500
400
300
200
100
02
B
A
V
S
= ±5V
f
C
= 5kHz
T
A
= 25°C
A. f
CLK
= 250kHz, (f
CLK
/f
C
) = 50:1
WITH EXTERNAL RC LOWPASS
FILTER (f
C
= 10kHz)
B. f
CLK
= 500kHz
(f
CLK
/f
C
) = 100:1
FREQUENCY (kHz)
1
THD + NOISE (dB)
5
1164-6 G14
–40
–45
–50
–55
–60
–65
–70
–75
–80
–85
–90
10
V
S
= ±5V, V
IN
= 1V
RMS
,
f
CLK
= 500kHz, f
C
= 10kHz,
(f
CLK
/f
C
) = 50:1, T
A
= 25°C,
WITH EXTERNAL RC LOWPASS
FILTER (f
– 3dB
= 20kHz)
(5 REPRESENTATIVE UNITS)
6
LTC1164-6
11646fa
CCHARA TERISTICS
UW
ATYPICALPER
FORCE
THD + Noise vs RMS Input for
Single 5V (Elliptic Response)
INPUT (V
RMS
)
THD + NOISE (dB)
1164-6 G18
–40
–45
–50
–55
–60
–65
–70
–75
–80
–85
–90
0.1 1 2
AB
A. GND = 2.5V
B. GND = 2V
(f
CLK
/f
C
) = 100:1 OR 50:1
f
IN
= 1kHz, T
A
= 25°C
THD + Noise vs RMS Input
(Elliptic Response)
INPUT (V
RMS
)
0.1
THD + NOISE (dB)
15
1164-6 G17
–40
–45
–50
–55
–60
–65
–70
–75
–80
–85
–90
V
S
= ±7.5V
V
S
= ±5V
(f
CLK
/f
C
) = 100:1 OR 50:1
f
IN
= 1kHz, T
A
= 25°C
Power Supply Current vs Power
Supply Voltage
POWER SUPPLY (V+ OR V–)
0
CURRENT (mA)
12
11
10
9
8
7
6
5
4
3
2
1
0
13 68
1164-6 G19
1024579
–55°C
25°C
125°C
2V/DIV
1ms/DIV 1164-6 G21
V
S
= ±7.5V, V
IN
= ±3V 100Hz SQUARE WAVE
f
CLK
= 800kHz, (f
CLK
/f
C
) = 160:1, f
CUTOFF
= 5kHz
LINEAR PHASE RESPONSE
Transient Response
Transient Response
1164-6 G20
1ms/DIV
V
S
= ±7.5V, V
IN
= ±3V 100Hz SQUARE WAVE
f
CLK
= 500kHz, (f
CLK
/f
C
) = 100:1, f
CUTOFF
= 5kHz
ELLIPTIC RESPONSE
2V/DIV
at least a 1µF capacitor (Figure 2). For single 5V operation
at the highest f
CLK
of 1MHz, Pins 3 and 5 should be biased
at 2V. This minimizes passband gain and phase variations
(see Typical Performance Characteristics curves: Maxi-
mum Passband for Single 5V, 50:1; and THD + Noise vs
RMS Input for Single 5V, 50:1).
V
+
(Pins 4, 12):The V
+
(Pin 4) and the V
–
(Pin 12) should
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-to-noise 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
–
(14-Lead Dual-In-Line Package)
PI FU CTIO S
U
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NC (Pins 1, 8, 13): Pins 1, 8, and 13 are not connected to
any internal circuit point on the device and should prefer-
ably be tied to analog ground.
V
IN
(Pin 2): The input pin is connected internally through
a 50k resistor tied to the inverting input of an op amp.
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 sur-
rounding 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
they should be bypassed to the analog ground plane with
7
LTC1164-6
11646fa
PI FU CTIO S
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(14-Lead Dual-In-Line Package)
buffer, Figure 3,can be used provided that its input common
mode range is well within the filter’s output swing. Pin 6 is
an intermediate filter output providing an unspecified 6th
order lowpass filter. Pin 6 should not be loaded.
ELLIPTIC/LINEAR PHASE (Pin 10): The DC level at this pin
selects the desired filter response, elliptic or linear phase
and determines the ratio of the clock frequency to the
cutoff frequency of the filter. Pin 10 connected to V
–
provides an elliptic lowpass filter with clock-to-f
CUTOFF
ratio of 100:1. Pin 10 connected to analog ground pro-
vides a linear phase lowpass filter with a clock- to-f
–3dB
ratio of 160:1 and a transient response overshoot of 1%.
When Pin 10 is connected to V
+
the clock-to-f
CUTOFF
ratio
is 50:1 and the filter response is elliptic. Bypassing Pin 10
to analog ground reduces the output DC offsets. 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.
CLK (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 1 shows the
clock’s low and high level threshold value for a 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 to
avoid coupling into 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 1 and 2.
1k
1164-6 F03
–
+
LT1006, f
C
< 5kHz
LT1200, f
C
> 5kHz
Figure 3. Buffer for Filter Output
V
–
(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.
V
OUT
(Pins 9, 6): Pin 9 is the specified output of the filter;
it can typically source or 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
could go above ground, a signal diode must be used to
clamp V. Figures 1 and 2 show typical connections for dual
and single supply operation.
1
2
3
4
5
6
7
14
13
12
11
10
9
8
V
IN
V
+
1k
V
–
V
OUT
LTC1164-6
DIGITAL SUPPLY
+
GND
CLOCK SOURCE
*
1164-6 F01
* OPTIONAL
0.1µF
0.1µF
Figure 1. Dual Supply Operation for fCLK/fCUTOFF = 100:1
Table 1. Clock Source High and Low Threshold Levels
POWER SUPPLY HIGH LEVEL LOW LEVEL
Dual Supply = ±7.5V ≥ 2.18V ≤ 0.5V
Dual Supply = ±5V ≥ 1.45V ≤ 0.5V
Dual Supply = ±2.5V ≥ 0.73V ≤ – 2.0V
Single Supply = 12V ≥ 7.80V ≤ 6.5V
Single Supply = 5V ≥ 1.45V ≤ 0.5V
Figure 2. Single Supply Operation for fCLK/fCUTOFF = 100:1
1
2
3
4
5
6
7
14
13
12
11
10
9
8
V
IN
V
+
1k
V
OUT
DIGITAL SUPPLY
+
GND
CLOCK SOURCE
1164-6 F02
+
LTC1164-6
0.1µF
1µF
10k
10k
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LTC1164-6
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Passband Response
The passband response of the LTC1164-6 is optimized for
a f
CLK
/f
CUTOFF
ratio of 100:1. Minimum passband ripple
occurs from 1Hz to 80% of f
CUTOFF
. Athough the passband
of the LTC1164-6 is optimized for ratio f
CLK
/f
CUTOFF
of
100:1, if a ratio of 50:1 is desired, connect a single pole
lowpass RC (f
–3dB
= 2 f
CUTOFF
) at the output of the filter.
The RC will make the passband gain response as flat as the
100:1 case. If the RC is omitted, and clock frequencies are
below 500kHz the passband gain will peak by 0.4dB at
90% f
CUTOFF
.
Table 2. Typical Passband Ripple with Single 5V Supply
(fCLK/fC) = 100:1, GND = 2V, 30kHz, Fixed Single Pole, Lowpass
RC Filter at Pin 9 (See Typical Applications)
PASSBAND PASSBAND GAIN
FREQUENCY (REFERENCED TO 0dB)
f
CUTOFF
= 1kHz f
CUTOFF
= 10kHz
T
A
= 25°CT
A
= 0°CT
A
= 25°CT
A
= 70°C
% of f
CUTOFF
(dB) (dB) (dB) (dB)
10 0.00 0.00 0.00 0.00
20 – 0.02 0.00 0.01 0.01
30 – 0.05 – 0.01 – 0.01 0.01
40 – 0.10 – 0.02 – 0.02 0.02
50 – 0.13 – 0.03 – 0.01 0.03
60 – 0.15 – 0.01 0.01 0.05
70 – 0.18 – 0.01 0.01 0.07
80 – 0.25 – 0.08 – 0.05 0.02
90 – 0.39 – 0.23 – 0.18 – 0.05
f
CUTOFF
– 2.68 – 2.79 – 2.74 – 2.68
The gain peaking can approximate a sin χ/χ correction for
some applications. (See Typical Performance Characteristics
curve, Passband vs Frequency and f
CLK
at f
CLK
/f
C
= 50:1.)
When the LTC1164-6 operates with a single 5V supply and its
cutoff frequency is clock-tuned to 10kHz, an output single
pole RC filter can also help maintain outstanding passband
flatness from 0°C to 70°C. Table 2 shows details.
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 3.
Table 3. Clock Feedthrough
V
S
50:1 100:1
±2.5V 60µV
RMS
60µV
RMS
±5V 100µV
RMS
200µV
RMS
±7.5V 150µV
RMS
500µV
RMS
Note: The clock feedthrough at ±2.5V supplies is imbedded in the wideband noise of the filter. (The
clock signal 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 fre-
quency 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 transient.
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 passband and it
cannot be reduced with post filtering. For instance, the
LTC1164-6 wideband noise at ±2.5V supply is 100µV
RMS
,
90µV
RMS
of which have frequency contents from DC up to
the filter’s cutoff frequency. The total wideband noise
(µV
RMS
) is nearly independent of the value of the clock.
The clock feedthrough specifications are not part of the
wideband noise.
Speed Limitations
The LTC1164-6 optimizes AC performance versus 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 on Table 4.
Aliasing
Aliasing is an inherent phenomenon of sampled data
systems and it occurs when input frequencies close to the
sampling frequency are applied. For the LTC1164-6 case,
an input signal whose frequency is in the range of f
CLK
±4%, will be aliased back into the filter’s passband. If, for
instance, an LTC1164-6 operating with a 100kHz clock
9
LTC1164-6
11646fa
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and 1kHz cutoff frequency receives a 98.5kHz, 10mV
RMS
input signal, a 1.5kHz, 10µV
RMS
alias signal will appear at
its output. When the LTC1164-6 operates with a clock-to-
cutoff frequency of 50:1, aliasing occurs at twice the clock
frequency. Table 5 shows details.
Table 4. Maximum VIN vs VS and fCLK
POWER SUPPLY MAXIMUM f
CLK
MAXIMUM V
IN
±7.5V 1.5MHz 1V
RMS
(f
IN
> 35kHz)
1MHz 3V
RMS
(f
IN
> 25kHz)
≥1MHz 0.7V
RMS
(f
IN
> 250kHz)
±5V 1MHz 2.5V
RMS
(f
IN
> 25kHz)
1MHz 0.5V
RMS
(f
IN
> 100kHz)
Single 5V 1MHz 0.7V
RMS
(f
IN
> 25kHz)
1MHz 0.5V
RMS
(f
IN
> 100kHz)
Table 5. Aliasing (fCLK = 100kHz)
INPUT FREQUENCY OUTPUT LEVEL OUTPUT FREQUENCY
(V
IN
= 1V
RMS
) (Relative to Input) (Aliased Frequency)
(kHz) (dB) (kHz)
f
CLK
/f
C
= 100:1, f
CUTOFF
= 1kHz
96 (or 104) –75.0 4.0
97 (or 103) – 68.0 3.0
98 (or 102) – 65.0 2.0
98.5 (or 101.5) – 60.0 1.5
99 (or 101) – 3.2 1.0
99.5 (or 100.5) – 0.5 0.5
f
CLK
/f
C
= 50:1, f
CUTOFF
= 2kHz
192 (or 208) –76.0 8.0
194 (or 206) – 68.0 6.0
196 (or 204) – 63.0 4.0
198 (or 202) – 3.4 2.0
199 (or 201) – 1.3 1.0
199.5(or 200.5) – 0.9 0.5
Table 6. Transient Response of LTC Lowpass Filters
DELAY RISE SETTLING OVER-
TIME* TIME** TIME*** SHOOT
LOWPASS FILTER (SEC) (SEC) (SEC) (%)
LTC1064-3 Bessel 0.50/f
C
0.34/f
C
0.80/f
C
0.5
LTC1164-5 Linear Phase 0.43/f
C
0.34/f
C
0.85/f
C
0
LTC1164-6 Linear Phase 0.43/f
C
0.34/f
C
1.15/f
C
1
LTC1264-7 Linear Phase 1.15/f
C
0.36/f
C
2.05/f
C
5
LTC1164-7 Linear Phase 1.20/f
C
0.39/f
C
2.20/f
C
5
LTC1064-7 Linear Phase 1.20/f
C
0.39/f
C
2.20/f
C
5
LTC1164-5 Butterworth 0.80/f
C
0.48/f
C
2.40/f
C
11
LTC1164-6 Elliptic 0.85/f
C
0.54/f
C
4.30/f
C
18
LTC1064-4 Elliptic 0.90/f
C
0.54/f
C
4.50/f
C
20
LTC1064-1 Elliptic 0.85/f
C
0.54/f
C
6.50/f
C
20
* To 50% ±5%, ** 10% to 90% ±5%, *** To 1% ±0.5%
8th Order Elliptic Lowpass Filter
(fCLK/f
C) = 50:1
1
2
3
4
5
6
7
14
13
12
11
10
9
8
LTC1164-6
VIN
VOUT
fCLK
V+
NOTES:
1. OPTIONAL OUTPUT BUFFER
1/2πRC = (2)(fCUTOFF)
2. PINS 1, 8, 13 CAN BE GROUNDED
OR LEFT FLOATING
1164-6 TA06
C
–
+
V–
0.1µF
R
V+
V–
LT®1006
0.1µF
V+
INPUT
90%
50%
10%
OUTPUT
tr
td
ts
1164-6 F04
RISE TIME (tr) = ±5%
0.54
fCUTOFF
SETTLING TIME (ts) = ±5%
(TO 1% of OUTPUT)
4.3
fCUTOFF
TIME DELAY (td) = GROUP DELAY ≈
(TO 50% OF OUTPUT)
0.85
fCUTOFF
Figure 4
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LTC1164-6
11646fa
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PPLICATITYPICAL
8th Order Elliptic Lowpass Filter (fCLK/f
C) = 100:1 8th Order Linear Phase Lowpass Filter (fCLK/f
C) = 160:1
8th Order 20kHz Cutoff, Elliptic Filter Operating with a Single 5V Supply and Driving 1k, 1000pF Load
THD + Noise vs Frequency
Gain vs Frequency
FREQUENCY (kHz)
1
THD + NOISE (dB)
5
1164-6 TA05
–40
–45
–50
–55
–60
–65
–70
–75
–80
–85
–90
10
V
S
= SINGLE 5V
IS = 5mA, 16TH ORDER
ELLIPTIC LOWPASS
V
IN
= 0.5V
RMS
f
CLK
= 540kHz
f
C
= 10kHz
FREQUENCY (kHz)
1
GAIN (dB)
10
1164-6 TA04
10
0
–10
–20
–30
–40
–50
–60
–70
–80
–90 30
V
S
= SINGLE 5V
I
S
= 5mA, 16TH ORDER
ELLIPTIC LOWPASS
f
CLK
= 540kHz
f
CUTOFF
= 10kHz
Single 5V, 16th Order Lowpass Filter fCUTOFF = 10kHz
1
2
3
4
5
6
7
14
13
12
11
10
9
8
VIN
5V
fCLK
1164-6 TA03
LTC1164-6
1µF
15k
10k
1
2
3
4
5
6
7
14
13
12
11
10
9
8
IC1
C1
0.01µF
R1
789Ω
5V
0.1µF
1k
5V
0.1µF5V
IC2
LTC1164-6
R2
7.89k
C2
0.001µF
VOUT
+
VS = SINGLE 5V, IS = 5mA TYP
16TH ORDER LOWPASS FILTER
FIXED fCUTOFF, fCLK = 540kHz
fCUTOFF = 10kHz
(fCLK/fC) = 54:1
1/2πR1C1 = 1/2πR2C2 = 2fCUTOFF
1
2
3
4
5
6
7
14
13
12
11
10
9
8
LTC1164-6
V
IN
V
OUT
f
CLK
= 1MHz
5V
NOTES:
1. TOTAL SUPPLY CURRENT I
S
= 4mA
(EXCLUDING OUTPUT LOAD CURRENT)
2. FLAT PASSBAND UP TO 18kHz,
f
–3dB
= 20kHz
3. THD + NOISE ≤ –70dB,
1V
P-P
≤ V
IN
≤ 3V
P-P
, f
IN
= 1kHz
1164-6 TA09
1k
–
+
510pF
LT1200
0.1µF
5V
10k
6.65k
0.1µF
10k
51.1k
5V
2
3
4
7
5V
1000pF
1k
1
2
3
4
5
6
7
14
13
12
11
10
9
8
LTC1164-6
VIN
VOUT
fCLK
1164-6 TA07
V–
0.1µF
0.1µF
V+
1
2
3
4
5
6
7
14
13
12
11
10
9
8
LTC1164-6
VIN
VOUT
fCLK
1164-6 TA08
V–
0.1µF
0.1µF
V+
11
LTC1164-6
11646fa
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.
PACKAGE DESCRIPTION
U
J Package
14-Lead CERDIP (Narrow .300 Inch, Hermetic)
(Reference LTC DWG # 05-08-1110)
N Package
14-Lead PDIP (Narrow .300 Inch)
(Reference LTC DWG # 05-08-1510)
J16 0801
.015 – .060
(0.380 – 1.520)
.100
(2.54)
BSC
.014 – .026
(0.360 – 0.660)
.045 – .065
(1.143 – 1.651)
.200
(5.080)
MAX
.125
(3.175)
MIN
.008 – .018
(0.203 – 0.457) 0° – 15°
12345678
.220 – .310
(5.588 – 7.874)
.840
(21.336)
MAX
.005
(0.127)
MIN 16 13 9
10
11121415
.025
(0.635)
RAD TYP
.300 BSC
(7.62 BSC)
.045 – .065
(1.143 – 1.65)
FULL LEAD
OPTION
.023 – .045
(0.584 – 1.143)
HALF LEAD
OPTION
CORNER LEADS OPTION
(4 PLCS)
NOTE: LEAD DIMENSIONS APPLY TO SOLDER DIP/PLATE
OR TIN PLATE LEADS
N14 1103
.020
(0.508)
MIN
.120
(3.048)
MIN
.130 ± .005
(3.302 ± 0.127)
.045 – .065
(1.143 – 1.651)
.065
(1.651)
TYP
.018 ± .003
(0.457 ± 0.076)
.005
(0.127)
MIN
.255 ± .015*
(6.477 ± 0.381)
.770*
(19.558)
MAX
31 24567
8910
11
1213
14
.008 – .015
(0.203 – 0.381)
.300 – .325
(7.620 – 8.255)
.325 +.035
–.015
+0.889
–0.381
8.255
()
NOTE:
1. DIMENSIONS ARE INCHES
MILLIMETERS
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .010 INCH (0.254mm)
.100
(2.54)
BSC
OBSOLETE PACKAGE
12
LTC1164-6
11646fa
© LINEAR TECHNOLOGY CORPORATION 1993
LT 0207 REV A • PRINTED IN USA
TYPICAL APPLICATION
U
RELATED PARTS
PART NUMBER DESCRIPTION COMMENTS
LTC1069-1 Low Power, 8th Order Elliptic Lowpass Operates from a Single 3.3V to ±5V Supply
LTC1069-6 Very Low Power 8th Order Elliptic Lowpass Optimized for 3V/5V Single Supply Operation, Consumes 1mA at 3V
8th Order Low Power, Clock-Tunable Elliptic Filter with Active RC Input Antialiasing Filter and Output Smoothing Filter
1
2
3
4
5
6
7
14
13
12
11
10
9
8
LTC1164-6
V
IN
V
OUT
f
CLK
V
–
f
C
= 1kHz
ATTENUATION AT 10kHz = –48dB
1164-6 TA10
0.1µF
V
+
0.1µF
V
–
–
+
1/2
LT1013
R3
5.62k
R2
76.8k
R1
1.15k
C3
0.001µF
C2
0.022µF
C1
0.1µF
R2
97.6k
R1
16.9k
C2
0.001µFC1
0.0047µF
f
C
= 1kHz
ATTENUATION AT 10kHz = –30dB
100Hz ≤ f
C
≤ 1kHz
10kHz ≤ f
CLK
≤ 100kHz
NOTES:
1. CLOCK-TUNABLE OVER ONE DECADE
OF CUTOFF FREQUENCY
2. BOTH INPUT AND OUTPUT RC ACTIVE
FILTERS ARE 0.1dB CHEBYSHEV FILTERS
WITH 1kHz RIPPLE BANDWIDTH
–
+
1/2
LT1013
SW Package
16-Lead Plastic Small Outline (Wide .300 Inch)
(Reference LTC DWG # 05-08-1620)
S16 (WIDE) 0502
NOTE 3
.398 – .413
(10.109 – 10.490)
NOTE 4
16 15 14 13 12 11 10 9
1
N
2345678
N/2
.394 – .419
(10.007 – 10.643)
.037 – .045
(0.940 – 1.143)
.004 – .012
(0.102 – 0.305)
.093 – .104
(2.362 – 2.642)
.050
(1.270)
BSC .014 – .019
(0.356 – 0.482)
TYP
0° – 8° TYP
NOTE 3
.009 – .013
(0.229 – 0.330)
.005
(0.127)
RAD MIN
.016 – .050
(0.406 – 1.270)
.291 – .299
(7.391 – 7.595)
NOTE 4
× 45°
.010 – .029
(0.254 – 0.737)
INCHES
(MILLIMETERS)
NOTE:
1. DIMENSIONS IN
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)
.420
MIN
.325 ±.005
RECOMMENDED SOLDER PAD LAYOUT
.045 ±.005
N
123 N/2
.050 BSC
.030 ±.005
TYP
PACKAGE DESCRIPTION
U
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507
●
www.linear.com
