LINER LTC1164-5CN

LTC1164-5
Low Power 8th Order
Pin Selectable Butterworth
or Bessel Lowpass Filter
DESCRIPTIO
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FEATURES
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Pin Selectable Butterworth or Bessel Response
4mA Supply Current with ±5V Supplies
fCUTOFF up to 20kHz
100µVRMS Wideband Noise
THD < 0.02% (50:1, VS = ±7.5V, VIN = 2VRMS)
Operates with a Single 5V Supply (1VRMS Input
Range)
60µVRMS Clock Feedthrough (Single 5V Supply)
Operates up to ±8V Supplies
TTL/CMOS-Compatible Clock Input
No External Components
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APPLICATIO S
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The LTC®1164-5 is a monolithic 8th order filter; it approximates either a Butterworth or a Bessel lowpass response.
The LTC1164-5 features clock-tunable cutoff frequency
and low power consumption (4.5mA with ±5V supplies
and 2.5mA with single 5V supply).
Low power operation is achieved without compromising
noise or distortion performance. With ±5V supplies and
10kHz cutoff frequency, the operating signal-to-noise
ratio is 86dB and the THD throughout the passband is
0.015%. Under the same conditions, a 77dB signal-tonoise ratio and distortion is obtained with a single 5V
supply while the clock feedthrough is kept below the noise
level. The maximum signal-to-noise ratio is 92dB.
The LTC1164-5 approximates an 8th order Butterworth
response with a clock-to-cutoff frequency ratio of 100:1
(Pin 10 to V –) or 50:1 double-sampled (Pin 10 to V + and
Pin 1 shorted to Pin 13). Double-sampling allows the input
signal frequency to reach the clock frequency before any
aliasing occurrence. An 8th order Bessel response can
also be approximated with a clock-to-cutoff frequency
ratio of 140:1 (Pin 10 to ground). With ±7.5V supply, ±5V
supply and single 5V supply, the maximum clock frequency of the LTC1164-5 is 1.5MHz, 1MHz, and 1MHz
respectively. The LTC1164-5 is pin-compatible with the
LTC1064-2 and LTC-1064-3.
Anti-Aliasing Filters
Battery-Operated Instruments
Telecommunications Filters
Smoothing Filters
, LTC and LT are registered trademarks of Linear Technology Corporation.
U
Frequency Response
TYPICAL APPLICATIO
Butterworth 20kHz Anti-Aliasing Filter
0
–10
8V
NC
14
–20
2
13
–30
3
12
4
11
LTC1164-5
5
10
6
9
7
8
–8V
CLK = 1MHz
TO V
+
VOUT
1164-5 TA01
WIDEBAND NOISE = 110µVRMS
THD IN PASSBAND < 0.02% AT VIN = 2VRMS
NOTE: THE CONNECTION FROM PIN 7 TO PIN 14
SHOULD BE MADE UNDER THE PACKAGE.
FOR 50:1 OPERATION CONNECT PIN 1 TO PIN 13
AS SHOWN. FOR 100:1 OR 150:1 OPERATION PINS 1
AND 13 SHOULD FLOAT. THE POWER SUPPLIES
SHOULD BE BYPASSED BY A 0.1µF CAPACITOR AS
CLOSE TO THE PACKAGE AS POSSIBLE.
GAIN (dB)
VIN
1
–40
–50
–60
–70
–80
1
10
FREQUENCY (kHz)
100
LTC1164-5 TA02
1
LTC1164-5
U
W W
W
ABSOLUTE
AXI U RATI GS
+
(Note 1)
–
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
LTC1164-5C ...................................... – 40°C to 85°C
LTC1164-5M .................................... – 55°C to 125°C
Storage Temperature Range ................ – 65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
U
W
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PACKAGE/ORDER I FOR ATIO
TOP VIEW
50:1 MODE
1
14 CONNECT 2
VIN
2
13 50:1 MODE
V–
GND
3
12
V+
4
11 CLK
GND
5
10 BUTT/BESS
LP6
CONNECT 1
6
9
7
J PACKAGE
14-LEAD CERDIP
8
ORDER PART
NUMBER
TOP VIEW
50:1 MODE 1
16 CONNECT 2
VIN 2
15 50:1 MODE
LTC1164-5CN
LTC1164-5CJ
LTC1164-5MJ
GND 3
14 V –
V+ 4
13 NC
GND 5
11 BUTT/BESS
LP6 7
NC
10 NC
CONNECT 1 8
N PACKAGE
14-LEAD PDIP
LTC1164-5CS
12 CLK
NC 6
VOUT
ORDER PART
NUMBER
9
VOUT
S PACKAGE
16-LEAD PLASTIC SW
TJMAX = 150°C, θJA = 65°C/W (J)
TJMAX = 110°C, θJA = 65°C/W (N)
TJMAX = 110°C, θJA = 85°C/W
Consult factory for Industrial grade parts.
ELECTRICAL CHARACTERISTICS
VS = ±7.5V, RL = 10k, fCLK = 400kHz, TA = Operating Temperature Range, unless otherwise specified.
MIN
LTC1164-5C
TYP
MAX
UNITS
●
●
– 0.5
– 0.5
– 0.10
0.10
0.25
0.25
dB
dB
fIN = 2kHz, (fCLK/fC) = 100:1
fIN = 4kHz, (fCLK/fC) = 50:1
●
●
– 0.45
– 0.35
– 0.20
– 0.10
0.17
0.40
dB
dB
Gain at 0.90fCUTOFF (Note 3)
fIN = 3.6kHz, (fCLK/fC) = 100:1
●
– 2.50
–1.90
–1.0
dB
Gain at 0.95fCUTOFF (Note 3)
fIN = 3.8kHz, (fCLK/fC) = 100:1
Gain at fCUTOFF (Note 3)
fIN = 4kHz, (fCLK/fC) = 100:1
fIN = 8kHz, (fCLK/fC) = 50:1
●
●
– 4.10
– 4.20
– 3.40
– 3.80
– 2.75
– 2.75
dB
dB
Gain at 1.44fCUTOFF (Note 3)
fIN = 5.76kHz, (fCLK/fC) = 100:1
●
– 20.5
–19.0
–17.0
dB
Gain at 2.0fCUTOFF (Note 3)
fIN = 8kHz, (fCLK/fC) = 100:1
●
– 45.0
– 43.0
– 41.0
dB
Gain with fCLK = 20kHz (Note 3)
fIN = 200Hz, (fCLK/fC) = 100:1
●
– 4.50
– 3.40
– 2.75
dB
Gain with VS = 2.375V (Note 3)
fIN = 400kHz, fIN = 2kHz, (fCLK/fC) = 100:1
fIN = 400kHz, fIN = 4kHz, (fCLK/fC) = 100:1
– 0.50
– 4.20
– 0.10
– 3.40
0.35
– 2.00
dB
dB
Input Frequency Range
(fCLK/fC) = 100:1
(fCLK/fC) = 50:1
PARAMETER
CONDITIONS
Passband Gain 0.1Hz at 0.25fCUTOFF (Note 3)
fIN = 1kHz, (fCLK/fC) = 100:1
fIN = 1kHz, (fCLK/fC) = 50:1
Gain at 0.50fCUTOFF (Note 3)
2
– 2.60
0 – <fCLK/2
0 – <fCLK
dB
kHz
kHz
LTC1164-5
ELECTRICAL CHARACTERISTICS
VS = ±7.5V, RL = 10k, fCLK = 400kHz, TA = Operating Temperature Range, unless otherwise specified.
MIN
LTC1164-5C
TYP
PARAMETER
CONDITIONS
Maximum fCLK
VS ≥ ±7.5V
VS = ±5.0V
VS = Single 5V (GND = 2V)
1.5
1.0
1.0
MHz
MHz
MHz
Clock Feedthrough
Input at GND, f = fCLK, Square Wave
±5V, (fCLK/fC) = 100:1
±5V, (fCLK/fC) = 50:1
200
100
µVRMS
µVRMS
100 ±5%
115 ±5%
µVRMS
µVRMS
Input at GND, 1Hz ≥ f < fCLK
±5V, (fCLK/fC) = 100:1
±5V, (fCLK/fC) = 50:1
Wideband Noise
Input Impedance
70
100
±1.25
±3.70
±5.40
±1.50
±4.10
±5.90
Output DC Voltage Swing
VS = ±2.375V
VS = ±5.0V
VS = ±7.5V
Output DC Offset
VS = ±5V, (fCLK/fC) = 100:1
± 50
Output DC Offset TempCo
VS = ±5V, (fCLK/fC) = 100:1
±100
Power Supply Current
VS = ±2.375V, TA ≥ 25°C
●
●
●
±160
4.5
7.0
●
±2.375
The ● denotes specifications which apply over the full operating
temperature range.
Note 1: Absolute Maximum Ratings are those values beyond which life of
the device may be impaired.
mV
µV/°C
●
Power Supply Range
kΩ
V
V
V
2.5
VS = ±7.5V, TA ≥ 25°C
UNITS
160
●
VS = ±5.0V, TA ≥ 25°C
MAX
4.0
4.5
7.0
8.0
11.0
12.5
mA
mA
mA
mA
mA
mA
±8
V
Note 2: Connecting any pin to voltages greater than V + or less than V –
may cause latchup. It is recommended that no sources operating from
external supplies be applied prior to power-up of the LTC1164-5.
Note 3: All gains are measured relative to passband gain. The filter cutoff
frequency is abbreviated as fCUTOFF or fC.
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Passband Gain and Phase
vs Frequency
Gain vs Frequency
B
C
GAIN (dB)
–20
–30
–40
–50
GAIN
–80
–10
0.1
–15
VS = ±5V
TA = 25°C
1
10
FREQUENCY (kHz)
50
LTC1164-5 • G01
–90
–5
–60
–70
0
0
GAIN (dB)
A
–10
VS = ±5V
fCLK = 50kHz
fCUTOFF = 1kHz
(50:1, PIN 10 TO V +,
PINS 1-13 SHORTED)
TA = 25°C
0.2
–180
PHASE (DEG)
A. fCLK = 100kHz
fCUTOFF = 1kHz
(100:1, PIN 10 TO V –)
B. fCLK = 375kHz
fCUTOFF = 2.68kHz
(140:1, PIN 10 GND)
C. fCLK = 500kHz
fCUTOFF = 10kHz
(50:1, PIN 10 TO V +,
PINS 1-13 SHORTED)
0
PHASE
0.4
0.8
0.6
FREQUENCY (kHz)
–270
1.0
LTC1164-5 • G02
3
LTC1164-5
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Passband Gain and Phase
vs Frequency
Passband Gain and Phase
vs Frequency
0
0
0
0
–180
VS = ±5V
fCLK = 100kHz
fCUTOFF = 1kHz
(100:1, PIN 10 TO V –)
TA = 25°C
–15
–20
0.2
0.4
0.8
0.6
FREQUENCY (kHz)
GAIN (dB)
–10
–5
–90
PHASE
–10
–270
–15
–360
–20
–180
VS = ±5V
fCLK = 150kHz
fCUTOFF = 1.07kHz
(140:1, PIN 10 TO GND)
TA = 25°C
0.2
1.0
–270
0.4
0.8
0.6
FREQUENCY (kHz)
Group Delay vs Frequency
Passband vs Frequency and fCLK
A. fCLK = 500kHz
(BUTTERWORTH 100:1)
fCUTOFF = 5kHz
B. fCLK = 750kHz
(BESSEL 140:1)
fCUTOFF = 5.36kHz
VS = ±7.5V
TA = 25°C
450
350
300
250
200
0
C D E
–1.0
–1.5
–2.0
–3.0
B
–3.5
–4.0
0
1.5
2.5 3.5 4.5
5.5
FREQUENCY (kHz)
6.5
VS = ±7.5V
50:1
TA = 25°C
0.1
7.5
1
FREQUENCY (kHz)
Maximum Passband over
Temperature for VS = ±7.5V, 50:1
0.5
0
GAIN (dB)
GAIN (dB)
0
–1.5
–2.0
–2.5
–3.5
LTC1164-5 • G07
E
–2.0
–3.0
30
C D
–1.5
–3.0
VS = ±7.5V
fCLK = 1.5MHz (50:1)
fCUTOFF = 30kHz
B
–1.0
–2.5
–4.0
4
A
–0.5
–1.0
10
FREQUENCY (kHz)
A. fCLK = 200kHz
fCUTOFF = 2kHz
B. fCLK = 500kHz
fCUTOFF = 5kHz
C. fCLK = 750kHz
fCUTOFF = 7.5kHz
D. fCLK = 1MHz
fCUTOFF = 10kHz
E. fCLK = 1.5MHz
fCUTOFF = 15kHz
0.5
TA = –40°C
1
30
Passband vs Frequency and fCLK
TA = 70°C
–0.5
10
LTC1164-5 • G06
LTC1164-5 • G05
–3.5
F
–2.5
100
0.5
A B
–0.5
A
50
A. fCLK = 200kHz
fCUTOFF = 4kHz
B. fCLK = 300kHz
fCUTOFF = 6kHz
C. fCLK = 500kHz
fCUTOFF = 10kHz
D. fCLK = 750kHz
fCUTOFF = 15kHz
E. fCLK = 1MHz
fCUTOFF = 20kHz
F. fCLK = 1.5MHz
fCUTOFF = 30kHz
0.5
GAIN (dB)
GROUP DELAY (µs)
400
150
–360
1.0
LTC1164-5 • G04
LTC1164-5 • G03
500
PHASE (DEG)
–90
PHASE (DEG)
GAIN (dB)
GAIN
–5
VS = ±7.5V
100:1
TA = 25°C
–4.0
0.1
1
FREQUENCY (kHz)
10
20
LTC1164-5 • G08
LTC1164-5
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Passband vs Frequency and fCLK
Passband vs Frequency and fCLK
0
GAIN (dB)
– 0.5
–1.0
–1.5
–2.0
A
–2.5
– 3.0
B
C D
E
0
– 4.0
0.1
A
–0.5
C
–1.5
–2.0
VS = ±5V
50:1
TA = 25°C
–3.5
–4.0
10
10
1
LTC1164-5 • G10
Maximum Passband over
Temperature for VS = ±5V, 50:1
0
0
TA = –40°C
A
–0.5
–1.0
–1.5
–2.0
–2.5
B
C
D E
–1.0
–1.5
–2.0
–2.5
–3.0
–3.0
VS = ±5V
fCLK = 1MHz
fCUTOFF = 20kHz
–3.5
–4.0
VS = ±5V
100:1
TA = 25°C
–3.5
1
10
–4.0
0.1
20
FREQUENCY (kHz)
1
FREQUENCY (kHz)
LTC1164-5 • G011
0.5
Passband vs Frequency and fCLK
0
TA = –40°C
–0.5
–1.0
–1.0
GAIN (dB)
–0.5
–1.5
–2.0
–3.5
–4.0
0.5
A
C
B
D
–1.5
–2.0
–2.5
–2.5
–3.0
A. fCLK = 250kHz
fCUTOFF = 5kHz
B. fCLK = 500kHz
fCUTOFF = 10kHz
C. fCLK = 750kHz
fCUTOFF = 15kHz
D. fCLK = 1MHz
fCUTOFF = 20kHz
0.5
TA = 70°C
0
10
LTC1164-5 • G12
Maximum Passband over
Temperature for VS = ±5V, 100:1
GAIN (dB)
A. fCLK = 200kHz
fCUTOFF = 2kHz
B. fCLK = 300kHz
fCUTOFF = 3kHz
C. fCLK = 500kHz
fCUTOFF = 5kHz
D. fCLK = 750kHz
fCUTOFF = 7.5kHz
E. fCLK = 1MHz
fCUTOFF = 10kHz
0.5
GAIN (dB)
GAIN (dB)
Passband vs Frequency and fCLK
TA = 70°C
–0.5
20
FREQUENCY (kHz)
LTC1164-5 • G09
0.5
D
–1.0
–3.0
1
FREQUENCY (kHz)
B
–2.5
VS = ±7.5V, 140:1
(BESSEL RESPONSE)
TA = 25°C
– 3.5
A. fCLK = 250kHz
fCUTOFF = 5kHz
B. fCLK = 500kHz
fCUTOFF = 10kHz
C. fCLK = 750kHz
fCUTOFF = 15kHz
D. fCLK = 1MHz
fCUTOFF = 20kHz
0.5
GAIN (dB)
A. fCLK = 150kHz
fCUTOFF = 1.07kHz
B. fCLK = 450kHz
fCUTOFF = 3.21kHz
C. fCLK = 750kHz
fCUTOFF = 5.36kHz
D. fCLK = 1MHz
fCUTOFF= 7.14kHz
E. fCLK = 1.5MHz
fCUTOFF = 10.71kHz
0.5
–3.0
VS = ±5V
fCLK = 1MHz (100:1)
fCUTOFF = 10kHz
1
VS = SINGLE 5V
50:1
TA = 25°C
–3.5
–4.0
10
10
1
20
FREQUENCY (kHz)
FREQUENCY (kHz)
LTC1164-5 • G13
LTC1164-5 • G14
5
LTC1164-5
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Maximum Passband over
Temperature for Single 5V, 50:1*
THD + Noise vs RMS Input, 50:1
THD + Noise vs RMS Input, 100:1
–40
–40
TA = 70°C
0
TA = –40°C
–50
THD + NOISE (dB)
–0.5
–1.0
–1.5
–2.0
–2.5
–3.0
VS = SINGLE 5V
fCLK = 1MHz (50:1)
fCUTOFF = 20kHz
–3.5
–4.0
1
SINGLE 5V
–60
–70
±7.5V
–80
–100
0.1
1
FREQUENCY (kHz)
LTC1164-5 • G015
THD + Noise vs Frequency
THD + Noise vs Frequency
VIN = 2VRMS
±7.5V, 100:1
fCLK = 500kHz
(5 REPRESENTATIVE
UNITS)
–60
–70
–80
–90
–90
1
10
1
20
–60
–70
–80
–90
–100
–100
3
2
FREQUENCY (kHz)
FREQUENCY (kHz)
4
5
–100
THD + Noise vs Frequency
THD + Noise vs Frequency
–40
–40
–50
VIN = 0.7VRMS
SINGLE 5V SUPPLY
50:1, fCLK = 500kHz
fC = 10kHz
(5 REPRESENTATIVE
UNITS)
–50
THD + NOISE (dB)
–60
–70
–80
–60
–54
–58
–70
–80
–90
–90
–100
–100
10
LTC1164-5 • G20
THD + Noise vs Frequency
VIN = 1VRMS
±5V, 100:1
fCLK = 500kHz
(5 REPRESENTATIVE
UNITS)
5
FREQUENCY (kHz)
1
LTC1164-5 • G19
LTC1164-5 • G18
–50
VIN = 1VRMS
±5V, 50:1
fCLK = 500kHz
(5 REPRESENTATIVE
UNITS)
–50
THD + NOISE (dB)
THD + NOISE (dB)
THD + NOISE (dB)
–80
5
–40
–50
–70
1
FREQUENCY (kHz)
LTC1164-5 • G17
THD + Noise vs Frequency
VIN = 2VRMS
±7.5V, 50:1
fCLK = 1MHz
(5 REPRESENTATIVE
UNITS)
–60
±7.5V
–80
–100
0.1
5
–40
–50
–70
LTC1164-5 • G16
–40
±5V
–60
–90
FREQUENCY (kHz)
THD + NOISE (dB)
SINGLE 5V
±5V
–90
10
fIN = 1kHz
fCLK = 500kHz
–50
THD + NOISE (dB)
GAIN (dB)
fIN = 1kHz
fCLK = 500kHz
THD + NOISE (dB)
0.5
–62
–66
VIN = 2VRMS
VS = ±7.5V, 140:1
fCLK = 750kHz
fC = 5.36kHz
(5 REPRESENTATIVE
UNITS)
–70
–74
–78
–82
–86
1
3
2
FREQUENCY (kHz)
4
5
1
5
FREQUENCY (kHz)
LTC1164-5 • G21
10
LTC1164-5 • G22
* See also Passband vs Frequency and fCLK for Single 5V, 50:1; THD + Noise vs RMS Input for Single 5V, 50:1;
and Maximum Passband for Single 5V, 50:1, for Two Ground Bias Levels.
6
–90
0.5
1
FREQUENCY (kHz)
5
LTC1164-5 • G23
LTC1164-5
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Maximum Passband for Single 5V,
50:1, for Two Ground Bias Levels
THD + Noise vs Input Voltage
–50
2.0
1.5
–58
1.0
–62
0.5
PHASE (DEG)
VS = ±2.5V
–66
VS = ±5V
–70
–40
TA = 70°C
fCLK = 1MHz
–74
–78
–45
0
–0.5
GND = 2V
–1.0
–1.5
–82
–2.0
VS = ±7.5V
–86
–90
0.1
1
INPUT VOLTAGE (VRMS)
5
–70
GND = 2.5V
–75
–85
–90
0.50
2
4
6
8 10 12 14 16 18 20 22
FREQUENCY (kHz)
0.75
1.00
1.25
INPUT (VRMS)
LTC1164-5 • TPC25
1.50
LTC1164-5 G26
Power Supply Rejection Ratio
vs Frequency
10
A. BUTTERWORTH
(fCLK / fCUTOFF = 100:1 OR 50:1)
B. BESSEL (fCLK /fCUTOFF = 140:1)
MAXIMUM PHASE DIFFERENCE
BETWEEN ANY TWO UNITS
(SAMPLE OF 50 UNITS)
VS ≥ ±5V
TA ≤ 70°C
fCLK ≤ 500KHz
fCUTOFF = 1kHz
0
–10
–20
PSRR (dB)
TOTAL PHASE DIFFERENCE (DEG)
GND = 2V
–3.0
10
4
A
–30
V+
–40
V–
–50
–60
B
2
–60
–65
–80
Phase Matching vs Frequency
6
–55
–2.5
LTC1164-5 • G24
8
fCLK = 1MHz
TA =25°C
–50
GND = 2.5V
THD + NOISE (dB)
fIN = 1kHz, 140:1
fCLK = 750kHz
–54
THD + WIDEBAND NOISE (dB)
THD + Noise vs RMS Input for
Single 5V, 50:1
–70
–80
0
0
1.0
0.4
0.6
0.8
0.2
FREQUENCY (FREQUENCY/fCUTOFF)
–90
1.2
20
100
1k
FREQUENCY (Hz)
10k
LTC1164-5 • G28
LTC1164-5 • G27
Power Supply Current vs Power
Supply Voltage
50k
Transient Response
VIN = ±3V, 500Hz Square Wave
Transient Response
VIN = ±3V, 500Hz Square Wave
12
11
–55°C
10
25°C
7
125°C
6
2V/DIV
8
2V/DIV
CURRENT (mA)
9
5
4
3
2
500µs/DIV
1
0
0
1
2 3 4
5 6 7 8
POWER SUPPLY (V + OR V –)
9
10
LTC1164-5 • G29
BUTTERWORTH RATIO = 100:1
fCLK = 500kHz
fC = 5kHz
VS = ±7.5V
1164-5 G30
500µs/DIV
1164-5 G31
BESSEL RATIO = 140:1
fCLK = 700kHz
fC = 5kHz
VS = ±7.5V
7
LTC1164-5
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PI FU CTIO S
Power Supply (Pins 4, 12)
Clock Input (Pin 11)
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 – can be more positive
than ground, a signal diode must be used to clamp V –.
Figures 1 and 2 show typical connections for dual and
single supply operation.
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.
V–
VIN
1
14
2
13
3
12
4
V+
0.1µF
LTC1164-5
*
0.1µF
1k
11
5
10
6
9
7
8
CLOCK SOURCE
+
GND
DIGITAL SUPPLY
* OPTIONAL (SEE TEXT)
VOUT
1164-5 F01
Figure 1. Dual Supply Operation for fCLK/fCUTOFF = 100:1
VIN
14
2
13
3
12
4
5V ≤ V + ≤ 16V
0.1µF
10k
10k
1
LTC1164-5
11
5
10
6
9
7
8
POWER SUPPLY
Dual Supply > ±3.4V
Dual Supply ≤ ±3.4V
Single Supply V+ > 6.8V, V – = 0V
Single Supply V+ < 6.8V, V – = 0V
HIGH LEVEL
≥ V +/3
≥ V +/3
≥ V +• 0.65
≥ V +/3
LOW LEVEL
≤ 0.5V
≤ V – + 0.5V
≤ 0.5V + 1/2V +
≤ 0.5V
Analog Ground (Pins 3, 5)
1k
CLOCK SOURCE
+
GND
DIGITAL SUPPLY
+
1µF
VOUT
1164-5 F02
Figure 2. Single Supply Operation for fCLK/fCUTOFF = 100:1
8
Table 1. Clock Source High and Low Threshold Levels
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 they should be
bypassed to the analog ground plane with at least a 1µF
capacitor (Figure 2). For single 5V operation at the highest
fCLK of 1MHz, Pins 3 and 5 should be biased at 2V. This
minimizes passband gain and phase variations (see Typical Performance Characteristics curves: Maximum Passband for Single 5V, 50:1; and THD + Noise vs RMS Input
for Single 5V, 50:1).
LTC1164-5
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PI FU CTIO S
Butterworth/Bessel (Pin 10)
The DC level at Pin 10 determines the ratio of the clock
frequency to the cutoff frequency of the filter. Pin 10 at V +
gives a 50:1 ratio and a Butterworth response (pins 1 to 13
are shorted for 50:1 only). Pin 10 at V – gives a 100:1
Butterworth response. Pin 10 at ground gives a Bessel
response and a ratio of 140:1. For single supply operation
the ratio is 50:1 when Pin 10 is at V + (pins 1 to 13 shorted),
100:1 when Pin 10 is at ground, and 140:1 when at 1/2
supply. 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.
Filter Input (Pin 2)
The input pin is connected internally through a 100k
resistor tied to the inverting input of an op amp.
Filter Output (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 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.
–
1k
LT1056
+
1164-5 F03
Figure 3. Buffer for Filter Output
External Connection (Pins 7, 14 and 1, 13)
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. When the clock to cutoff frequency ratio is
set at 50:1, Pin 1 should be shorted to Pin 13; if not, the
passband will exhibit 1dB of gain peaking and it will deviate
from a Butterworth response. Pin 1 is the inverting input
of an internal op amp and it should preferably be 0.2 inches
away from any other circuit trace.
NC (Pin 8)
Pin 8 is not connected to any internal circuit point on the
device and should be preferably tied to analog ground.
U
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APPLICATIO 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 (Pin 9). The clock feedthrough is tested
with the input pin (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 2.
Table 2. Output Clock Feedthrough
VS
50:1
100:1
±2.5V
60µVRMS
60µVRMS
±5V
100µVRMS
200µVRMS
±7.5V
150µVRMS
500µVRMS
Note: The clock feedthrough at ±2.5V supplies is imbedded in the
wideband noise of the filter. The clock waveform is a square wave.
9
LTC1164-5
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APPLICATIO S I FOR ATIO
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 (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
LTC1164-5 wideband noise at ±2.5V supply is 100µVRMS,
95µVRMS of which have frequency contents from DC up to
the filter’s cutoff frequency. The total wideband noise
(µRMS) is nearly independent of the value of the clock. The
clock feedthrough specifications are not part of the wideband noise.
Speed Limitations
The LTC1164-5 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 in Table 3.
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 LTC1164-5 case
at 100:1, an input signal whose frequency is in the range
of fCLK ±2.5% will be aliased back into the filter’s passband. If, for instance, an LTC1164-5 operating with a
100kHz clock and 1kHz cutoff frequency receives a 98kHz
10mV input signal, a 2kHz 56µV alias signal will appear at
its output. When the LTC1164-5 operates with a clock-tocutoff frequency of 50:1, aliasing occurs at twice the clock
frequency. Table 4 shows details.
Table 4. Aliasing Data (fCLK = 100kHz, VS = ±5V)
INPUT FREQUENCY
(VIN = 1VRMS)
MAXIMUM fCLK
OUTPUT FREQUENCY
(Aliased Frequency)
(fCLK/fC) = 100:1, fCUTOFF = 1kHz
97.0kHz
97.5kHz
98.0kHz
98.5kHz
99.0kHz
99.5kHz
–102.0dB
– 65.0dB
– 45.0dB
– 23.0dB
– 4.0dB
– 0.3dB
3.0kHz
2.5kHz
2.0kHz
1.5kHz
1.0kHz
0.5kHz
(fCLK/fC) = 50:1, fCUTOFF = 2kHz
197.0kHz
197.5kHz
198.0kHz
198.5kHz
199.0kHz
199.5kHz
– 23.0dB
–12.0dB
– 5.0dB
–1.8dB
–1.0dB
– 0.8dB
3.0kHz
2.5kHz
2.0kHz
1.5kHz
1.0kHz
0.5kHz
Table 5. Transient Response of LTC Lowpass Filters
MAXIMUM VIN
LOWPASS FILTER
DELAY
TIME*
(SEC)
LTC1064-3 Bessel
LTC1164-5 Bessel
LTC1164-6 Bessel
0.50/fC
0.43/fC
0.43/fC
0.34/fC
0.34/fC
0.34/fC
0.80/fC
0.85/fC
1.15/fC
0.5
0
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
LTC1164-6 Elliptic
0.80/fC
0.85/fC
0.48/fC
0.54/fC
2.40/fC
4.30/fC
11
18
LTC1064-4 Elliptic
LTC1064-1 Elliptic
0.90/fC
0.85/fC
0.54/fC
0.54/fC
4.50/fC
6.50/fC
20
20
Table 3. Maximum VIN vs VS and fCLK
POWER SUPPLY
OUTPUT LEVEL
(Relative to Input)
VS = ±7.5V
1.5MHz
1VRMS (fIN > 35kHz)
0.5VRMS (fIN > 250kHz)
VS = ±7.5V
1.0MHz
3VRMS (fIN > 25kHz)
0.7VRMS (fIN > 250kHz)
VS = ±5.0V
1.0MHz
2.5VRMS (fIN > 25kHz)
0.5VRMS (fIN > 100kHz)
Single 5V
1.0MHz
0.7VRMS (fIN > 25kHz)
0.5VRMS (fIN > 100kHz)
RISE
TIME**
(SEC)
SETTLING
TIME***
(SEC)
OVERSHOOT
(%)
* To 50% ±5%, ** 10% to 90% ±5%, *** To 1% ±0.5%
10
LTC1164-5
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TYPICAL APPLICATIO S
Single 5V, IS = 5.2mA, 16th Order Clock-Tunable Lowpass Filter,
fCLK/fCUTOFF = 60:1, –75dB Attenuation at 2.3 fCUTOFF
1
VIN
LTC1164-5
2
3
4
5V
0.1µF
15k
+
1µF
IC1
14
1
13
2
12
3
11
5
10
6
7
10k
14
LTC1164-5
12
4
5V
10
9
6
9
8
7
8
0.1µF
5V
THD + Noise vs Frequency
–40
0
–45
–10
–50
–20
–55
THD + NOISE (dB)
GAIN (dB)
VOUT
1164-5 F04
Gain vs Frequency
–30
–40
–50
–60
VS = SINGLE 5V
VIN = 0.5VRMS
fCLK = 600kHz
fC = 10kHz
–60
–65
–70
–75
–80
VS = SINGLE 5V
fCLK = 600kHz
fCUTOFF = 10kHz
–85
–90
1
5V
1k
10
–80
11
IC2
5
fCLK
–70
13
10
FREQUENCY (kHz)
–90
30
5
FREQUENCY (kHz)
1
LTC1164-5 • TA04
LTC1164-5 • TA03
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PACKAGE DESCRIPTIO
10
Dimensions in inches (millimeters) unless otherwise noted.
J Package
14-Lead CERDIP (Narrow 0.300, Hermetic)
(LTC DWG # 05-08-1110)
CORNER LEADS OPTION
(4 PLCS)
0.023 – 0.045
(0.584 – 1.143)
HALF LEAD
OPTION
0.045 – 0.068
(1.143 – 1.727)
FULL LEAD
OPTION
0.005
(0.127)
MIN
0.840
(21.336)
MAX
16
15
14
13
12
11
10
9
0.220 – 0.310
(5.588 – 7.874)
0.025
(0.635)
RAD TYP
1
2
3
4
5
6
7
8
0.200
(5.080)
MAX
0.300 BSC
(0.762 BSC)
0.015 – 0.060
(0.380 – 1.520)
0.008 – 0.018
(0.203 – 0.457)
0° – 15°
NOTE: LEAD DIMENSIONS APPLY TO SOLDER DIP/PLATE
OR TIN PLATE LEADS
0.125
(3.175)
MIN
0.045 – 0.068
(1.143 – 1.727)
0.100 ± 0.010
(2.540 ± 0.254)
0.014 – 0.026
(0.360 – 0.660)
J16 1197
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.
11
LTC1164-5
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TYPICAL APPLICATIO S
8th Order Butterworth Lowpass Filter
fCLK/fC = 50:1
VIN
1
14
2
13
3
V+
4
+
0.1µF
VIN
12
LTC1164-5
11
5
10
6
9
7
8
V–
fCLK
8th Order Linear Phase Lowpass Filter
fCLK/fC = 140:1
8th Order Butterworth Lowpass Filter
fCLK/fC = 100:1
V
0.1µF
+
+
0.1µF
V+
VOUT
1
14
1
14
2
13
2
13
3
12
3
12
4
11
4
11
LTC1164-5
5
10
6
9
7
8
VIN
V–
fCLK
0.1µF
V+
0.1µF
VOUT
LTC1164-5
5
10
6
9
7
8
V–
0.1µF
fCLK
VOUT
1164-5 TA06
1164-5 TA07
1164-5 TA05
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PACKAGE DESCRIPTIO
Dimensions in inches (millimeters) unless otherwise noted.
N Package
14-Lead PDIP (Narrow 0.300)
(LTC DWG # 05-08-1510)
0.130 ± 0.005
(3.302 ± 0.127)
0.300 – 0.325
(7.620 – 8.255)
0.770*
(19.558)
MAX
0.045 – 0.065
(1.143 – 1.651)
0.020
(0.508)
MIN
0.065
(1.651)
TYP
0.009 – 0.015
(0.229 – 0.381)
+0.035
0.325 –0.015
0.005
(0.125)
MIN
0.100 ± 0.010
(2.540 ± 0.254)
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm)
(
8.255
+0.889
–0.381
)
13
12
11
10
9
8
1
2
3
4
5
6
7
0.255 ± 0.015*
(6.477 ± 0.381)
0.018 ± 0.003
(0.457 ± 0.076)
0.125
(3.175)
MIN
14
N14 1197
SW Package
16-Lead Plastic Small Outline (Wide 0.300)
(LTC DWG # 05-08-1620)
0.291 – 0.299**
(7.391 – 7.595)
0.010 – 0.029 × 45°
(0.254 – 0.737)
0.398 – 0.413*
(10.109 – 10.490)
0.093 – 0.104
(2.362 – 2.642)
0.037 – 0.045
(0.940 – 1.143)
16
15
14
13
12
11
10
9
0° – 8° TYP
0.009 – 0.013
(0.229 – 0.330)
0.050
(1.270)
TYP
NOTE 1
0.016 – 0.050
(0.406 – 1.270)
0.004 – 0.012
(0.102 – 0.305)
0.394 – 0.419
(10.007 – 10.643)
NOTE 1
0.014 – 0.019
(0.356 – 0.482)
TYP
NOTE:
1. 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
*DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
**DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
1
2
3
4
5
6
7
8
S16 (WIDE) 0396
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LTC1069-1
Low Power, 8th Order Elliptic Lowpass Filter
Operates from a Single 3.3V to ±5V Supply
LTC1069-6
Very Low Power, 8th Order Elliptic Lowpass Filter
Optimized for 3V/5V Single Supply Operation, Consumes 1mA at 3V
12
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408)432-1900 ● FAX: (408) 434-0507 ● www.linear-tech.com
11645as, sn11645 LT/TP 1098 2K REV A • PRINTED IN USA
 LINEAR TECHNOLOGY CORPORATION 1993