LTC1068 Series - Clock-Tunable, Quad Second Order, Filter Building Blocks

LTC1068 Series
Clock-Tunable, Quad
Second Order, Filter Building Blocks
FEATURES
DESCRIPTION
Four Identical 2nd Order Filter Sections in an
SSOP Package
n 2nd Order Section Center Frequency Error:
± 0.3% Typical and ±0.8% Maximum
n Low Noise per 2nd Order Section, Q ≤ 5:
LTC1068-200 50µVRMS, LTC1068 50µVRMS
LTC1068-50 75µVRMS, LTC1068-25 90µVRMS
n Low Power Supply Current: 4.5mA, Single 5V,
LTC1068-50
n Operation with ± 5V Power Supply, Single 5V
Supply or Single 3.3V Supply
The LTC®1068 product family consists of four monolithic
clock-tunable filter building blocks. Each product contains
four matched, low noise, high accuracy 2nd order switchedcapacitor filter sections. An external clock tunes the center
frequency of each 2nd order filter section. The LTC1068
products differ only in their clock-to-center frequency
ratio. The clock-to-center frequency ratio is set to 200:1
(LTC1068-200), 100:1 (LTC1068), 50:1 (LTC1068-50) or
25:1 (LTC1068-25). External resistors can modify the clockto-center frequency ratio. High performance, quad 2nd
order, dual 4th order or 8th order filters can be designed
with an LTC1068 family product. Designing filters with an
LTC1068 product is fully supported by FilterCAD™ filter
design software for Windows.
n
APPLICATIONS
Lowpass or Highpass Filters:
LTC1068-200, 0.5Hz to 25kHz; LTC1068, 1Hz to
50kHz; LTC1068-50, 2Hz to 50kHz; LTC1068-25,
4Hz to 200kHz
n Bandpass or Bandreject (Notch) Filters:
LTC1068-200, 0.5Hz to 15kHz; LTC1068, 1Hz to
30kHz; LTC1068-50, 2Hz to 30kHz; LTC1068-25,
4Hz to 140kHz
n
The LTC1068 products are available in a 28-pin SSOP
surface mount package. A customized version of an
LTC1068 family product can be obtained in a 16-lead SO
package with internal thin-film resistors. Please contact
LTC Marketing for details.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
FilterCAD is a trademark of Linear Technology Corporation. All other trademarks are the property
of their respective owners.
TYPICAL APPLICATION
Dual, Matched, 4th Order Butterworth Lowpass Filters, Clock-Tunable Up
to 200kHz f – 3dB = fCLK/25, 4th Order Filter Noise = 60µVRMS
R12 14k
1
R21 14k
2
R31 20k
3
4
5
6
7
8
5V
0.1µF
9
10
11
VIN2
R13 20k
R33 20k
12
R23 14k
13
14
INV B
HPB/NB
INV C
HPC/NC
BPB
BPC
LPB
SB
NC
LPC
LTC1068-25
AGND
V
+
NC
SA
LPA
BPA
HPA/NA
INVA
SC
V–
NC
CLK
NC
SD
LPD
BPD
HPD/ND
INVD
Gain vs Frequency
28
27
R22 20k
26
R32 10k
10
0
25
–10
VOUT1
24
–20
23
1µF
22
21
–5V
fCLK = (25)(f – 3dB)
20
GAIN (dB)
VIN1
R11 20k
–30
–40
–50
–60
–70
19
18
17
R34 10k
16
R24 20k
VOUT2
–80
0.1
1
RELATIVE FREQUENCY [fIN/(f – 3dB)]
10
1068 TA02
15
R14 14k
1068 TA01
1068fc
1
LTC1068 Series
ABSOLUTE MAXIMUM RATINGS
(Note 1)
Total Supply Voltage (V + to V –).................................12V
Power Dissipation............................................... 500mW
Input Voltage at Any Pin.......V – – 0.3V ≤ VIN ≤ V + + 0.3V
Storage Temperature Range.................... –65°C to 150°C
Operating Temperature Range
LTC1068C................................................. 0°C to 70°C
LTC1068I............................................. –40°C to 85°C
Lead Temperature (Soldering, 10 sec)................... 300°C
PIN CONFIGURATION
TOP VIEW
INV B
1
28 INV C
HPB/NB
2
27 HPC/NC
BPB
3
26 BPC
LPB
4
25 LPC
SB
5
24 SC
NC
6
23 V–
AGND
7
22 NC
V+
8
NC
TOP VIEW
INV B
1
24 INV C
HPB/NB
2
23 HPC/NC
BPB
3
22 BPC
LPB
4
21 LPC
SB
5
20 SC
AGND
6
V+
19 V–
21 CLK
7
18 CLK
9
20 NC
SA
8
17 SD
LPA
9
16 LPD
BPA 10
15 BPD
SA 10
19 SD
LPA 11
18 LPD
BPA 12
17 BPD
HPA/NA 13
INV A 14
HPA/NA 11
14 HPD/ND
INV A 12
16 HPD/ND
13 INV D
N PACKAGE
24-LEAD PDIP
15 INV D
TJMAX = 110°C, θJA = 65°C/W
G PACKAGE
28-LEAD PLASTIC SSOP
TJMAX = 110°C, θJA = 95°C/W
ORDER INFORMATION
LEAD FREE FINISH
TAPE AND REEL
PART MARKING
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LTC1068CG#PBF
LTC1068CG#TRPBF
LTC1068
28-Lead Plastic SSOP
0°C to 70°C
LTC1068IG#PBF
LTC1068IG#TRPBF
LTC1068
28-Lead Plastic SSOP
–40°C to 85°C
LTC1068-200CG#PBF
LTC1068-200CG#TRPBF
LTC1068
28-Lead Plastic SSOP
0°C to 70°C
LTC1068-200IG#PBF
LTC1068-200IG#TRPBF
LTC1068
28-Lead Plastic SSOP
–40°C to 85°C
LTC1068-50CG#PBF
LTC1068-50CG#TRPBF
LTC1068
28-Lead Plastic SSOP
0°C to 70°C
LTC1068-50IG#PBF
LTC1068-50IG#TRPBF
LTC1068
28-Lead Plastic SSOP
–40°C to 85°C
LTC1068-25CG#PBF
LTC1068-25CG#TRPBF
LTC1068
28-Lead Plastic SSOP
0°C to 70°C
LTC1068-25IG#PBF
LTC1068-25IG#TRPBF
LTC1068
28-Lead Plastic SSOP
–40°C to 85°C
LTC1068CN#PBF
NA
LTC1068
24-Lead PDIP
0°C to 70°C
LTC1068IN#PBF
NA
LTC1068
24-Lead PDIP
–40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges.
Consult LTC Marketing for information on nonstandard lead based finish parts.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
1068fc
2
LTC1068 Series
ELECTRICAL
CHARACTERISTICS
LTC1068 (Internal Op Amps). The l denotes the specifications which apply
over the full operating temperature range, otherwise specifications are at VS = ± 5V, TA = 25°V, unless otherwise noted.
PARAMETER
CONDITIONS
MIN
Operating Supply Voltage Range
TYP
3.14
Voltage Swings
VS = 3.14V, RL = 5k (Note 2)
VS = 4.75V, RL = 5k (Note 3)
VS = ±5V, RL = 5k
Output Short-Circuit Current (Source/Sink)
VS = ± 4.75V
VS = ±5V
DC Open-Loop Gain
UNITS
± 5.5
V
1.6
3.2
±4.1
VP-P
VP-P
V
17/6
20/15
mA
mA
RL = 5k
85
dB
GBW Product
VS = ±5V
6
MHz
Slew Rate
VS = ±5V
10
V/µs
Analog Ground Voltage (Note 4)
VS = 5V, Voltage at AGND
l
l
l
1.2
2.6
±3.4
MAX
2.5V ±2%
V
LTC1068 (Complete Filter) VS = ± 5V, TA = 25°V, unless otherwise noted.
PARAMETER
CONDITIONS
MIN
TYP
MAX
Clock-to-Center Frequency Ratio (Note 5)
VS = 4.75V, fCLK = 1MHz, Mode 1 (Note 3),
fO = 10kHz, Q = 5, VIN = 0.5VRMS,
R1 = R3 = 49.9k, R2 = 10k
l
VS = ± 5V, fCLK = 1MHz, Mode 1,
fO = 10kHz, Q = 5, VIN = 1VRMS,
R1 = R3 = 49.9k, R2 = 10k
l
Clock-to-Center Frequency Ratio,
Side-to-Side Matching (Note 5)
VS = 4.75V, fCLK = 1MHz, Q = 5 (Note 3)
VS = ±5V, fCLK = 1MHz, Q = 5
Q Accuracy (Note 5)
VS = 4.75V, fCLK = 1MHz, Q = 5 (Note 3)
VS = ±5V, fCLK = 1MHz, Q = 5
UNITS
100 ± 0.3
100 ±0.8
100 ±0.9
%
%
100 ± 0.3
100 ±0.8
100 ±0.9
%
%
l
l
±0.25
±0.25
±0.9
±0.9
%
%
l
l
±1
±1
±3
±3
%
%
fO Temperature Coefficient
±1
ppm/°C
Q Temperature Coefficient
±5
ppm/°C
DC Offset Voltage (Note 5)
(See Table 1)
VS = ±5V, fCLK = 1MHz, VOS1
(DC Offset of Input Inverter)
l
0
±15
mV
VS = ± 5V, fCLK = 1MHz, VOS2
(DC Offset of First Integrator)
l
±2
±25
mV
VS = ±5V, fCLK = 1MHz, VOS3
(DC Offset of Second Integrator)
l
±5
±40
mV
Clock Feedthrough
VS = ± 5V, fCLK = 1MHz
0.1
mVRMS
Max Clock Frequency (Note 6)
VS = ±5V, Q ≤ 2.0, Mode 1
5.6
MHz
Power Supply Current
VS = 3.14V, fCLK = 1MHz (Note 2)
VS = 4.75V, fCLK = 1MHz (Note 3)
VS = ±5V, fCLK = 1MHz
l
l
l
3.5
6.5
9.5
8
11
15
mA
mA
mA
1068fc
3
LTC1068 Series
ELECTRICAL
CHARACTERISTICS
LTC1068-200 (Internal Op Amps). The l denotes the specifications which
apply over the full operating temperature range, otherwise specifications are at VS = ± 5V, TA = 25°V, unless otherwise noted.
PARAMETER
CONDITIONS
MIN
Operating Supply Voltage Range
TYP
3.14
UNITS
±5.5
V
Voltage Swings
VS = 3.14V, RL = 5k (Note 2)
VS = 4.75V, RL = 5k (Note 3)
VS = ±5V, RL = 5k
Output Short-Circuit Current (Source/Sink)
VS = ± 4.75V
VS = ±5V
DC Open-Loop Gain
RL = 5k
85
dB
GBW Product
VS = ±5V
6
MHz
Slew Rate
VS = ±5V
10
V/µs
Analog Ground Voltage (Note 4)
VS = 5V, Voltage at AGND
l
l
l
1.2
2.6
±3.4
MAX
1.6
3.2
±4.1
VP-P
VP-P
V
17/6
20/15
mA
mA
2.5V ±2%
V
LTC1068-200 (Complete Filter) VS = ±5V, TA = 25°V, unless otherwise noted.
PARAMETER
CONDITIONS
MIN
TYP
MAX
Clock-to-Center Frequency Ratio (Note 5)
VS = 4.75V, fCLK = 1MHz, Mode 1 (Note 3),
fO = 5kHz, Q = 5, VIN = 0.5VRMS,
R1 = R3 = 49.9k, R2 = 10k
l
VS = ± 5V, fCLK = 1MHz, Mode 1,
fO = 5Hz, Q = 5, VIN = 1VRMS,
R1 = R3 = 49.9k, R2 = 10k
l
Clock-to-Center Frequency Ratio,
Side-to-Side Matching (Note 5)
VS = 4.75V, fCLK = 1MHz, Q = 5 (Note 3)
VS = ±5V, fCLK = 1MHz, Q = 5
Q Accuracy (Note 5)
VS = 4.75V, fCLK = 1MHz, Q = 5 (Note 3)
VS = ±5V, fCLK = 1MHz, Q = 5
200 ±0.3
200 ±0.8
200 ±0.9
%
%
200 ±0.3
200 ±0.8
200 ±0.9
%
%
l
l
± 0.25
± 0.25
±0.9
±0.9
%
%
l
l
±1
±1
±3
±3
%
%
fO Temperature Coefficient
±1
Q Temperature Coefficient
DC Offset Voltage (Note 5)
(See Table 1)
UNITS
ppm/°C
±5
ppm/°C
VS = ±5V, fCLK = 1MHz, VOS1
(DC Offset of Input Inverter)
l
0
±15
mV
VS = ± 5V, fCLK = 1MHz, VOS2
(DC Offset of First Integrator)
l
±2
±25
mV
VS = ±5V, fCLK = 1MHz, VOS3
(DC Offset of Second Integrator)
l
±5
±40
mV
Clock Feedthrough
VS = ± 5V, fCLK = 1MHz
0.1
mVRMS
Max Clock Frequency (Note 6)
VS = ±5V, Q ≤ 2.0, Mode 1
5.6
MHz
Power Supply Current
VS = 3.14V, fCLK = 1MHz (Note 2)
VS = 4.75V, fCLK = 1MHz (Note 3)
VS = ±5V, fCLK = 1MHz
l
l
l
3.5
6.5
9.5
8
11
15
mA
mA
mA
1068fc
4
LTC1068 Series
ELECTRICAL
CHARACTERISTICS
LTC1068-50 (Internal Op Amps). The l denotes the specifications which
apply over the full operating temperature range, otherwise specifications are at VS = ± 5V, TA = 25°V, unless otherwise noted.
PARAMETER
CONDITIONS
MIN
Operating Supply Voltage Range
TYP
3.14
Voltage Swings
VS = 3.14V, RL = 5k (Note 2)
VS = 4.75V, RL = 5k (Note 3)
VS = ±5V, RL = 5k
Output Short-Circuit Current (Source/Sink)
VS = ± 3.14V
VS = ±5V
DC Open-Loop Gain
UNITS
± 5.5
V
1.8
3.6
±4.1
VP-P
VP-P
V
17/6
20/15
mA
mA
RL = 5k
85
dB
GBW Product
VS = ±5V
4
MHz
Slew Rate
VS = ±5V
7
V/µs
Analog Ground Voltage (Note 4)
VS = 5V, Voltage at AGND
l
l
l
1.2
2.6
±3.4
MAX
2.175V ±2%
V
LTC1068-50 (Complete Filter) VS = ±5V, TA = 25°V, unless otherwise noted.
PARAMETER
CONDITIONS
MIN
TYP
MAX
Clock-to-Center Frequency Ratio (Note 5)
VS = 3.14V, fCLK = 250kHz, Mode 1 (Note 2),
fO = 5kHz, Q = 5, VIN = 0.34VRMS,
R1 = R3 = 49.9k, R2 = 10k
l
VS = ± 5V, fCLK = 500kHz, Mode 1,
fO = 10kHz, Q = 5, VIN = 1VRMS,
R1 = R3 = 49.9k, R2 = 10k
l
Clock-to-Center Frequency Ratio,
Side-to-Side Matching (Note 5)
VS = 3.14V, fCLK = 250kHz, Q = 5 (Note 2)
VS = ±5V, fCLK = 500kHz, Q = 5
Q Accuracy (Note 5)
VS = 3.14V, fCLK = 250kHz, Q = 5 (Note 2)
VS = ±5V, fCLK = 500kHz, Q = 5
50 ± 0.3
50 ±0.8
50 ±0.9
%
%
50 ± 0.3
50 ±0.8
50 ±0.9
%
%
l
l
± 0.25
± 0.25
±0.9
±0.9
%
%
l
l
±1
±1
±3
±3
%
%
fO Temperature Coefficient
±1
Q Temperature Coefficient
DC Offset Voltage (Note 5)
(See Table 1)
UNITS
ppm/°C
±5
ppm/°C
VS = ±5V, fCLK = 500kHz, VOS1
(DC Offset of Input Inverter)
l
0
±15
mV
VS = ± 5V, fCLK = 500kHz, VOS2
(DC Offset of First Integrator)
l
–2
±25
mV
VS = ±5V, fCLK = 500kHz, VOS3
(DC Offset of Second Integrator)
l
–5
±40
mV
Clock Feedthrough
VS = ± 5V, fCLK = 500kHz
0.16
mVRMS
Max Clock Frequency (Note 6)
VS = ±5V, Q ≤ 1.6, Mode 1
3.4
MHz
Power Supply Current
VS = 3.14V, fCLK = 250kHz (Note 2)
VS = 4.75V, fCLK = 250kHz (Note 3)
VS = ±5V, fCLK = 500kHz
l
l
l
3.0
4.3
6.0
5
8
11
mA
mA
mA
1068fc
5
LTC1068 Series
ELECTRICAL
CHARACTERISTICS
LTC1068-25 (Internal Op Amps). The l denotes the specifications which
apply over the full operating temperature range, otherwise specifications are at VS = ± 5V, TA = 25°V, unless otherwise noted.
PARAMETER
CONDITIONS
MIN
Operating Supply Voltage Range
TYP
3.14
Voltage Swings
VS = 3.14V, RL = 5k (Note 2)
VS = 4.75V, RL = 5k (Note 3)
VS = ±5V, RL = 5k
Output Short-Circuit Current (Source/Sink)
VS = ± 4.75V
VS = ±5V
DC Open-Loop Gain
UNITS
± 5.5
V
1.6
3.4
±4.1
VP-P
VP-P
V
17/6
20/15
mA
mA
RL = 5k
85
dB
GBW Product
VS = ±5V
6
MHz
Slew Rate
VS = ±5V
10
V/µs
Analog Ground Voltage (Note 4)
VS = 5V, Voltage at AGND
l
l
l
1.2
2.6
±3.4
MAX
2.5V ±2%
V
LTC1068-25 (Complete Filter) VS = ± 5V, TA = 25°V, unless otherwise noted.
PARAMETER
CONDITIONS
MIN
TYP
MAX
Clock-to-Center Frequency Ratio (Note 5)
VS = 4.75V, fCLK = 500kHz, Mode 1 (Note 3),
fO = 20kHz, Q = 5, VIN = 0.5VRMS,
R1 = R3 = 49.9k, R2 = 10k
l
VS = ± 5V, fCLK = 1MHz, Mode 1,
fO = 40kHz, Q = 5, VIN = 1VRMS,
R1 = R3 = 49.9k, R2 = 10k
l
Clock-to-Center Frequency Ratio,
Side-to-Side Matching (Note 5)
VS = 4.75V, fCLK = 500kHz, Q = 5 (Note 3)
VS = ±5V, fCLK = 1MHz, Q = 5
Q Accuracy (Note 5)
VS = 4.75V, fCLK = 500kHz, Q = 5 (Note 3)
VS = ±5V, fCLK = 1MHz, Q = 5
25 ±0.3
25 ±0.8
25 ±0.9
%
%
25 ±0.3
25 ±0.8
25 ±0.9
%
%
l
l
± 0.25
± 0.25
±0.9
±0.9
%
%
l
l
±1
±1
±3
±3
%
%
fO Temperature Coefficient
±1
Q Temperature Coefficient
DC Offset Voltage (Note 5)
(See Table 1)
UNITS
ppm/°C
±5
ppm/°C
VS = ± 5V, fCLK = 1MHz, VOS1
(DC Offset of Input Inverter)
l
0
±15
mV
VS = ± 5V, fCLK = 1MHz, VOS2
(DC Offset of First Integrator)
l
–2
±25
mV
VS = ±5V, fCLK = 1MHz, VOS3
(DC Offset of Second Integrator)
l
–5
±40
mV
Clock Feedthrough
VS = ± 5V, fCLK = 1MHz
0.25
mVRMS
Max Clock Frequency (Note 6)
VS = ±5V, Q ≤ 1.6, Mode 1
5.6
MHz
Power Supply Current
VS = 3.14V, fCLK = 1MHz (Note 2)
VS = 4.75V, fCLK = 1MHz (Note 3)
VS = ±5V, fCLK = 1MHz
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: Production testing for single 3.14V supply is achieved by using
the equivalent dual supplies of ±1.57V.
Note 3: Production testing for single 4.75V supply is achieved by
using the equivalent dual supplies of ±2.375V.
l
l
l
3.5
6.5
9.5
8
11
15
mA
mA
mA
Note 4: Pin 7 (AGND) is the internal analog ground of the device. For
single supply applications this pin should be bypassed with a 1µF
capacitor. The biasing voltage of AGND is set with an internal resistive
divider from Pin 8 to Pin 23 (see Block Diagram).
Note 5: Side D is guaranteed by design.
Note 6: See Typical Performance Characteristics.
1068fc
6
LTC1068 Series
ELECTRICAL CHARACTERISTICS
Table 1. Output DC Offsets One 2nd Order Section
MODE
VOSN
VOSBP
VOSLP
1
VOS1[(1/Q) + 1 + ||HOLP||] – VOS3 /Q
VOS3
VOSN – VOS2
1b
VOS1[(1/Q) + 1 + R2/R1] – VOS3 /Q
VOS3
~(VOSN – VOS2)(1 + R5/R6)
2
[VOS1(1 + R2/R1 + R2/R3 + R2/R4) – VOS3(R2/R3)X
[R4/(R2 + R4)] + VOS2[R2/(R2 + R4)]
VOS3
VOSN – VOS2
3
VOS2
VOS3
VOS1[1 + R4/R1 + R4/R2 + R4/R3] – VOS2(R4/R2) – VOS3(R4/R3)
TYPICAL PERFORMANCE CHARACTERISTICS
40
40
35
30
25
20
25
20
15
10
10
0
A
0
10
B
40
30
20
50
60
CENTER FREQUENCY, fO (kHz)
0
70
55
40
(FOR MODE 2, R4 < 10R2)
TYPICAL MAXIMUM Q
35
30
25
20
15
A
5
0
0
4
B
B
25
20
15
0
60
45
40
(FOR MODE 2, R4 ≥ 10R2)
35
30
25
20
B
15
1068 G04
0
C
A
0
4
55
4
12 16 20 24 28 32
8
CENTER FREQUENCY, fO (kHz)
1068 G03
45
40
(FOR MODE 2, R4 < 10R2)
35
30
25
20
C
15
B
10
12 16 20 24 28
8
CENTER FREQUENCY, fO (kHz)
C
A: VS = 3.3V, fCLK(MAX) = 1.1MHz
B: VS = 5V, fCLK(MAX) = 2.1MHz
C: VS = ±5V, fCLK(MAX) = 3.6MHz
50
A
5
0
B
LTC1068-50
Maximum Q vs Center Frequency
(Modes 2, 3)
5
32
A
1068 G02
A: VS = 3.3V, fCLK(MAX) = 1.1MHz
B: VS = 5V, fCLK(MAX) = 2.1MHz
C: VS = ±5V, fCLK(MAX) = 3.6MHz
50
10
C
12 16 20 24 28
8
CENTER FREQUENCY, fO (kHz)
30
5
C
40
30
20
50
10
CENTER FREQUENCY, fO (kHz)
0
55
TYPICAL MAXIMUM Q
45
10
(FOR MODE 2, R4 ≥ 10R2)
35
LTC1068-50
Maximum Q vs Center Frequency
(Modes 1, 1b, 2)
A: VS = 3.3V, fCLK(MAX) = 1.2MHz
B: VS = 5V, fCLK(MAX) = 3.2MHz
C: VS = ±5V, fCLK(MAX) = 6.1MHz
50
A
1068 G01
LTC1068-200
Maximum Q vs Center Frequency
(Modes 2, 3)
40
10
5
C
45
A: VS = 3.3V, fCLK(MAX) = 1.2MHz
B: VS = 5V, fCLK(MAX) = 3.2MHz
C: VS = ±5V, fCLK(MAX) = 6.1MHz
50
30
15
5
A. VS = 3.3V, fCLK(MAX) = 1MHz
B. VS = 5V, fCLK(MAX) = 3MHz
C. VS = ±5V, fCLK(MAX) = 5MHz
(FOR MODE 2 R4 < 10R2)
45
MAXIMUM Q
MAXIMUM Q
35
55
50
A. VS = 3.3V, fCLK(MAX) = 1.5MHz
B. VS = 5V, fCLK(MAX) = 3.4MHz
C. VS = ±5V, fCLK(MAX) = 5.6MHz
(FOR MODE 2 R4 ≥ 10R2)
45
LTC1068-200
Maximum Q vs Center Frequency
(Modes 1, 1b, 2)
TYPICAL MAXIMUM Q
50
LTC1068
Maximum Q vs Center Frequency
(Modes 2, 3)
TYPICAL MAXIMUM Q
LTC1068
Maximum Q vs Center Frequency
(Modes 1, 1b, 2)
32
1068 G05
0
0
4
12 16 20 24 28
8
CENTER FREQUENCY, fO (kHz)
32
1068 G06
1068fc
7
LTC1068 Series
TYPICAL PERFORMANCE CHARACTERISTICS
LTC1068-25
Maximum Q vs Center Frequency
(Modes 1, 1b, 2)
40
45
35
30
25
20
15
10
5
0
B
A
0
32
A: VS = 3.3V, fCLK(MAX) = 1MHz
B: VS = 5V, fCLK(MAX) = 3MHz
C: VS = ±5V, fCLK(MAX) = 5MHz
(FOR MODE 2, R4 < 10R2)
50
40
TYPICAL MAXIMUM Q
45
TYPICAL MAXIMUM Q
55
A: VS = 3.3V, fCLK(MAX) = 1.2MHz
B: VS = 5V, fCLK(MAX) = 3.4MHz
C: VS = ±5V, fCLK(MAX) = 6.1MHz
(FOR MODE 2, R4 ≥ 10R2)
50
35
30
25
20
15
10
C
0
224
B
A
5
64
96 128 160 192
CENTER FREQUENCY, fO (kHz)
0
32
C
64
96 128 160
FREQUENCY, fO (kHz)
192
1068 G07
MODE 3
–0.05
MODE 1
–0.10
VS = ±5V
Q = 5, REFERENCE
CENTER FREQUENCY
WITH fCLK = 0.75MHz
–0.15
–0.20
–0.25
0.75 1.25 1.75 2.25 2.75 3.25 3.75 4.25
CLOCK FREQUENCY (MHz)
1068 G10
0.4
0
–0.2
–0.4
–0.6
0.75 1.25 1.75 2.25 2.75 3.25 3.75 4.25
CLOCK FREQUENCY (MHz)
1068 G09
LTC1068-25 Center Frequency
Variation vs Clock Frequency
1.8
0.3
MODE 3
0.2
0.1
0
VS = ±5V
Q = 5, REFERENCE
CENTER FREQUENCY
WITH fCLK = 0.5MHz
–0.1
–0.2
0.5
0.75
1.3
0.8
MODE 1
0.3
MODE 3
1.0
1.25
1.5
1.75
CLOCK FREQUENCY (MHz)
0
2.0
250
250
250
3.3V
50
0
NOISE (µVRMS)
NOISE (µVRMS)
5V
100
±5V
5V
150
3.3V
100
5
10
15
20
Q
25
30
35
40
1068 G13
0
3.0
1.5
2.0
2.5
CLOCK FREQUENCY (MHz)
3.5
1068 G12
5V ±5V
200
3.3V
150
100
50
50
0
1.0
LTC1068-25 Noise vs Q
300
200
0.5
1068 G11
LTC1068-50 Noise vs Q
±5V
VS = ±5V
Q = 5, REFERENCE
CENTER FREQUENCY
WITH fCLK = 0.5MHz
MODE 1
300
150
MODE 1
0.2
300
200
MODE 3
0.6
0.4
LTC1068/LTC1068-200
Noise vs Q
NOISE (µVRMS)
0.8
BATTERY VOLTAGE (V)
0.10
CENTER FREQUENCY VARIATION (% ERROR)
CENTER FREQUENCY VARIATION (% ERROR)
0.15
VS = ±5V
Q = 5, REFERENCE
CENTER FREQUENCY
WITH fCLK = 0.75MHz
1.0
LTC1068-50 Center Frequency
Variation vs Clock Frequency
0.20
0
224
1.2
1068 G08
LTC1068-200 Center Frequency
Variation vs Clock Frequency
0.05
LTC1068 Center Frequency
Variation vs Clock Frequency
CENTER FREQUENCY VARIATION (% ERROR)
55
LTC1068-25
Maximum Q vs Center Frequency
(Modes 2, 3)
0
5
10
15
20
Q
25
30
35
40
1068 G14
0
0
5
10
15
20
Q
25
30
35
40
1068 G15
1068fc
8
LTC1068 Series
TYPICAL PERFORMANCE CHARACTERISTICS
Noise Increase vs R2/R4 Ratio
(Mode 3)
Noise Increase vs R5/R6 Ratio
(Mode 1b)
2.0
RELATIVE NOISE INCREASE
(REFERENCE NOISE WHEN R5/R6 = 0.02)
RELATIVE NOISE INCREASE
(REFERENCE NOISE WHEN R2/R4 = 1)
2.0
1.9
1.8
1.7
1.6
1.5
1.4
1.3
1.2
1.1
0
0.2 0.3
0.4
0.5 0.6 0.7
R2/R4 RATIO
0.8
0.9
1.9
1.8
1.7
1.6
1.5
1.4
1.3
1.2
1.1
0
1.0
0
0.5
1.0
1.5 2.0
2.5
R5/R6 RATIO
3.0
1068 G17
1068 G16
LTC1068/LTC1068-200/
LTC1068-25 Power Supply
Current vs Power Supply
LTC1068-50 Power Supply
Current vs Power Supply
8
9.5
25°C
8.5
POWER SUPPLY CURRENT (mA)
POWER SUPPLY CURRENT (mA)
10.5
70°C
–20°C
7.5
6.5
5.5
4.5
3.5
3
4
7
9
6
8
5
TOTAL POWER SUPPLY (V)
10
1068 G18
7
25°C
6
70°C
–20°C
5
4
3
2
3
4
7
9
6
8
5
TOTAL POWER SUPPLY (V)
10
1068 G19
1068fc
9
LTC1068 Series
PIN FUNCTIONS
Power Supply Pins
Clock Input Pin
The V + and V– pins 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-to-noise ratio of the filter. 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 2 shows the clock’s low and high level
threshold values for dual or single supply operation.
Analog Ground Pin
POWER SUPPLY
The filter’s 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 single supply
operation, AGND should be bypassed to the analog ground
plane with at least a 0.47µF capacitor (Figure 2).
Two internal resistors bias the analog ground pin. For the
LTC1068, LTC1068-200 and LTC1068-25, the voltage at
the analog ground pin (AGND) for single supply is 0.5 × V+
and for the LTC1068-50 it is 0.435 × V+.
ANALOG
GROUND
PLANE
1
28
2
27
3
26
4
25
5
24
6
V+
7
0.1µF
8
STAR
SYSTEM
GROUND
V–
23
LTC1068
0.1µF
21
9
20
19
11
18
12
17
HIGH LEVEL
LOW LEVEL
Dual Supply = ± 5V
≥ 1.53V
≤ 0.53V
Single Supply = 5V
≥ 1.53V
≤ 0.53V
Single Supply = 3.3V
≥ 1.20V
≤ 0.53V
A pulsed generator can be used as a clock source provided
the high level ON time is at least 25% of the pulse period.
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
ANALOG
GROUND
PLANE
1
28
2
27
DEVICE
RA RB
LTC1068
LTC1068-200 10k 10k
LTC1068-25
LTC1068-50 11.3k 8.6k
3
26
4
25
VAGND
22
10
Table 2. Clock Source High and Low Threshold Levels
5
V+
8
0.1µF
0.47µF
(1µF FOR
STOPBAND
FREQUENCIES
≤1kHz)
22
RA
20
19
11
18
12
17
16
15
14
15
14
STAR
SYSTEM
GROUND
1068 F01
Figure 1. Dual Supply Ground Plane Connections
21
9
16
DIGITAL GROUND
RB
10
13
200Ω
24
23
7
13
CLOCK
SOURCE
LTC1068
6
FOR MODE 3, THE S NODE
SHOULD BE TIED TO PIN 7 (AGND)
CLOCK
SOURCE
200Ω
DIGITAL GROUND
1068 F02
Figure 2. Single Supply Ground Plane Connections
1068fc
10
LTC1068 Series
PIN FUNCTIONS
path. A 200Ω 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
Output Pins
LT®1354
+
1068 F03
Each 2nd order section of an LTC1068 device has three
outputs that typically source 17mA and sink 6mA. Driving coaxial cables or resistive loads less than 20k will
degrade the total harmonic distortion performance of
any filter design. When evaluating the distortion or noise
performance of a particular filter design implemented with
a LTC1068 device, the final output of the filter should be
buffered with a wideband, noninverting high slew rate
amplifier (Figure 3).
Figure 3. Wideband Buffer
In a printed circuit layout any signal trace, clock source
trace or power supply trace should be at least 0.1 inches
away from any inverting input pins
Summing Input Pins
Inverting Input Pins
These are voltage input pins. If used, they should be driven
with a source impedance below 5k. When they are not
used, they should be tied to the analog ground pin.
These pins are the inverting inputs of internal op amps
and are susceptible to stray capacitive coupling from low
impedance signal outputs and power supply lines.
The summing pin connections determine the circuit topology (mode) of each 2nd order section. Please refer to
Modes of Operation.
BLOCK DIAGRAM
HPA/NA
(13)
INV A
(14)
–
AGND
(7)
+
BPA
(12)
+
–
+
+
+
+
+
LPC
(25)
BPC
(26)
+
CLK (21)
RB*
V– (23)
+
NC (9)
LPD
(18)
BPD
(17)
SC
(24)
+
AGND (7)
RA*
NC (6)
Σ
–
HPD/ND
(16)
–
*THE RATIO RA/RB VARIES ±2%
V+ (8)
SB
(5)
+
INV D
(15)
Σ
LPB
(4)
–
HPC/NC
(27)
–
+
BPB
(3)
SA
(10)
+
INV C
(28)
+
DEVICE
RA RB
LTC1068
LTC1068-200 10k 10k
LTC1068-25
LTC1068-50 11.3k 8.6k
–
HPB/NB
(2)
INV B
(1)
Σ
LPA
(11)
NC (20)
NC (22)
Σ
+
+
–
SD
(19)
PIN 28-LEAD SSOP PACKAGE
1068 BD
1068fc
11
LTC1068 Series
MODES OF OPERATION
Linear Technology’s universal switched-capacitor filters
are designed for a fixed internal, nominal fCLK/fO ratio. The
fCLK/fO ratio is 100 for the LTC1068, 200 for the LTC1068200, 50 for the LTC1068-50 and 25 for the LTC1068-25.
Filter designs often require the fCLK/fO ratio of each section
to be different from the nominal ratio and in most cases
different from each other. Ratios other than the nominal
value are possible with external resistors. Operating modes
use external resistors, connected in different arrangements
to realize different fCLK/fO ratios. By choosing the proper
mode, the fCLK/fO ratio can be increased or decreased from
the part’s nominal ratio.
The choice of operating mode also effects the transfer
function at the HP/N pins. The LP and BP pins always give
the lowpass and bandpass transfer functions respectively,
regardless of the mode utilized. The HP/N pins have a
different transfer function depending on the mode used.
Mode 1 yields a notch transfer function. Mode 3 yields a
highpass transfer function. Mode 2 yields a highpass notch
transfer function (i.e., a highpass with a stopband notch).
More complex transfer functions, such as lowpass notch,
allpass or complex zeros, are achieved by summing two
or more of the LP, BP or HP/N outputs. This is illustrated
in sections Mode 2n and Mode 3a.
Choosing the proper mode(s) for a particular application
is not trivial and involves much more than just adjusting
the fCLK/fO ratio. Listed here are four of the nearly twenty
modes available. To make the design process simpler and
quicker, Linear Technology has developed the FilterCAD
for Widows design software. FilterCAD is an easy-to-use,
powerful and interactive filter design program. The designer can enter a few filter specifications and the program
produces a full schematic. FilterCAD allows the designer
to concentrate on the filter’s transfer function and not get
bogged down in the details of the design. Alternatively,
those who have experience with the Linear Technology
family of parts can control all of the details themselves.
For a complete listing of all the operating modes, consult
the appendices of the FilterCAD manual or the Help files
in FilterCAD. FilterCAD can be obtained free of charge on
the Linear Technology web site (www.linear.com) or you
can order the FilterCAD CD-ROM by contacting Linear
Technology Marketing.
Mode 1
In Mode 1, the ratio of the external clock frequency to
the center frequency of each 2nd order section is internally fixed at the part’s nominal ratio. Figure 4 illustrates
Mode 1 providing 2nd order notch, lowpass and bandpass outputs. Mode 1 can be used to make high order
Butterworth lowpass filters; it can also be used to make
low Q notches and for cascading 2nd order bandpass
functions tuned at the same center frequency. Mode 1 is
faster than Mode 3.
Please refer to the Operating Limits paragraph under Applications Information for a guide to the use of capacitor CC.
CC
R3
R2
VIN
R1
–
S
+
+
AGND
N
Σ
HOLP = HON
LP
–
fCLK
;f =f
RATIO n O
R2
R3
R3
Q=
;H =–
;H
=–
R1 OBP
R1
R2 ON
fO =
BP
DEVICE
RATIO
LTC1068
100
LTC1068-200 200
LTC1068-50
50
LTC1068-25
25
1068 F04
Figure 4. Mode 1, 2nd Order Filter Providing Notch,
Bandpassing and Lowpass Outputs
Mode 1b
Mode 1b is derived from Mode 1. In Mode 1b (Figure 5)
two additional resistors R5 and R6 are added to lower the
amount of voltage fed back from the lowpass output into
the input of the SA (or SB) switched-capacitor summer.
This allows the filter’s clock-to-center frequency ratio to
be adjusted beyond the part’s nominal ratio. Mode 1b
maintains the speed advantages of Mode 1 and should
be considered an optimum mode for high Q designs with
fCLK to fCUTOFF (or fCENTER) ratios greater than the part’s
nominal ratio.
The parallel combination of R5 and R6 should be kept
below 5k.
Please refer to the Operating Limits paragraph under Applications Information for a guide to the use of capacitor CC.
1068fc
12
LTC1068 Series
MODES OF OPERATION
CC
CC
R6
R4
R5
R3
R3
R2
R2
VIN
R1
N
–
S
+
+
Σ
VIN
–
√
(
–
)
–
R3
√ R4 ; Q = 1.005 (R2) √ R4 (1 – (RATIO)(0.32)(R4)
)
R3
R2
R3
HOHP = – R2 ; HOBP = –
R1
R1
1068 F05
(
1
1–
R3
(RATIO)(0.32)(R4)
1068 F06
CC
R4
R3
R2
VIN
Please refer to the Operating Limits paragraph under Applications Information for a guide to the use of capacitor CC.
R1
HPN
–
+
+
S
Σ
–
DEVICE
RATIO
LTC1068
100
LTC1068-200 200
LTC1068-50
50
LTC1068-25
25
AGND
fCLK
RATIO
fCLK
√ 1 + R4 ; f = RATIO
R3
1
Q = 1.005 ( ) 1 + R2
R2 √
R4
R3
1–
( (RATIO)(0.32)(R4)
)
fO =
HOHPN = –
HOBP = –
R2
n
R2
(AC GAIN, f >> fO); HOHPN = – R2
R1
R1
R3
R1
(
1068 F07
1
1 + R2
R4
(
1
; HOLP = – R2
R1
R3
1–
(RATIO)(0.32)(R4)
)
LP
BP
Mode 2
Please refer to the Operating Limits paragraph under Applications Information for a guide to the use of capacitor CC.
)
; HOLP = – R4
R1
Figure 6. Mode 3, 2nd Order Section Providing
Highpass, Bandpass and Lowpass Outputs
Mode 3
Mode 2 is a combination of Mode 1 and Mode 3, shown
in Figure 7. With Mode 2, the clock-to-center frequency
ratio, fCLK/fO, is always less than the part’s nominal ratio.
The advantage of Mode 2 is that it provides less sensitivity
to resistor tolerances than does Mode 3. Mode 2 has a
highpass notch output where the notch frequency depends
solely on the clock frequency and is therefore less than
the center frequency, fO.
1
R2
DEVICE
RATIO
LTC1068
100
LTC1068-200 200
LTC1068-50
50
LTC1068-25
25
Figure 5. Mode 1b, 2nd Order Filter Providing Notch,
Bandpass and Lowpass Outputs
In Mode 3, the ratio of the external clock frequency to
the center frequency of each 2nd order section can be
adjusted above or below the parts nominal ratio. Figure 6
illustrates Mode 3, the classical state variable configuration,
providing highpass, bandpass and lowpass 2nd order filter
functions. Mode 3 is slower than Mode 1. Mode 3 can be
used to make high order all-pole bandpass, lowpass and
highpass filters.
Σ
LP
BP
1/4 LTC1068
f
fO = CLK
RATIO
AGND
S
+
+
f
R6 ; f = f
fO = CLK
RATIO (R6 + R5) n O
R3
R6 ; H = – R2 ; H
Q = R3
=–
R1
R1 OBP
R2 (R6 + R5) ON
R2 R6 + R5
HOLP = –
R6
R1
√
R1
DEVICE
RATIO
LTC1068
100
LTC1068-200 200
LTC1068-50
50
LTC1068-25
25
AGND
HP
LP
BP
)
(DC GAIN)
1
1 + R2
R4
(
)
Figure 7. Mode 2, 2nd Order Filter Providing Highpass
Notch, Bandpass and Lowpass Outputs
1068fc
13
LTC1068 Series
APPLICATIONS INFORMATION
Operating Limits
The Maximum Q vs Center Frequency (fO) graphs, under
Typical Performance Characteristics, define an upper
limit of operating Q for each LTC1068 device 2nd order
section. These graphs indicate the power supply, fO and
Q value conditions under which a filter implemented with
an LTC1068 device will remain stable when operated at
temperatures of 70°C or less. For a 2nd order section, a
bandpass gain error of 3dB or less is arbitrarily defined
as a condition for stability.
the operating signal-to-noise ratio. Most of its frequency
contents lie within the filter passband and cannot be
reduced with post filtering. For a notch filter the noise of
the filter is centered at the notch 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.
For a specific filter design, the total noise depends on the
Q of each section and the cascade sequence. Please refer
to the Noise vs Q graphs under the Typical Performance
Characteristics.
When the passband gain error begins to exceed 1dB, the
use of capacitor CC will reduce the gain error (capacitor CC
is connected from the lowpass node to the inverting node
of a 2nd order section). Please refer to Figures 4 through 7.
The value of CC can be best determined experimentally,
and as a guide it should be about 5pF for each 1dB of
gain error and not to exceed 15pF. When operating an
LTC1068 device near the limits defined by the Maximum Q
vs Frequency graphs, passband gain variations of 2dB or
more should be expected.
Aliasing is an inherent phenomenon of switched-capacitor
filters and occurs when the frequency of the input signals
that produce the strongest aliased components have a
frequency, fIN, such as (fSAMPLING – fIN) that falls into the
filter’s passband. For an LTC1068 device the sampling
frequency is twice fCLK. If the input signal spectrum is
not band-limited, aliasing may occur.
Clock Feedthrough
Demonstration Circuit 104
Clock feedthrough is defined as the RMS value of the
clock frequency and its harmonics that are present at the
filter’s output pins. The clock feedthrough is tested with
the filter’s input grounded and depends on PC board layout
and on the value of the power supplies. With proper layout
techniques, the typical values of clock feedthrough are
listed under Electrical Characteristics.
DC104 is a surface mount printed circuit board for the
evaluation of Linear Technology’s LTC1068 product family
in a 28-lead SSOP package. The LTC1068 product family
consists of four monolithic clock-tunable filter building
blocks.
Any parasitic switching transients during the rising and
falling 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, can be greatly reduced by adding a
simple RC lowpass network at the final filter output. This
RC 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 is used to determine
Aliasing
Demo Board 104 is available in four assembled versions:
Assembly 104-A features the low noise LTC1068CG (clockto-center frequency ratio = 100), assembly 104-B features
the low noise LTC1068-200CG (clock-to-center frequency
ratio = 200), assembly 104-C features the high frequency
LTC1068-25CG (clock-to-center frequency ratio = 25) and
assembly 104-D features the low power LTC1068-50CG
(clock-to-center frequency ratio = 50).
All DC104 boards are assembled with input, output and
power supply test terminals, a 28-lead SSOP filter device
(LTC1068CG Series), a dual op amp in an SO-8 for input
or output buffers and decoupling capacitors for the filter
and op amps. The filter and dual op amps share the power
1068fc
14
LTC1068 Series
APPLICATIONS INFORMATION
supply inputs to the board. Jumpers JPA to JPD on the
board configure the filter’s second order circuit modes,
jumper JP1 configures the filter for dual or single supply
operation and jumpers JP2 (A-D) to JP3 (A-D) configure
the op amp buffers as inverting or noninverting. Surface
mount pads are available on the board for 1206 size sur-
face mount resistors. The printed circuit layout of DC104
is arranged so that most of the resistor connections for
one 8th order filter or two 4th order filters are available
on the board. A resistor makes a connection between two
filter nodes on the board and for most filter designs, no
wiring is required.
DC104 Component Side Silkscreen
DC104 Component Side
DC104 Solder Side
1068fc
15
E4
SGND
E13
CLK
E3
VIN1
E12
FGND
E2
SGND
VIN2
E1
E11
V–
E10
SGND
E9
V+
RI1
R12
C1
0.1µF
1
2
JPA
ASSEMBLED AS NONINVERTING
BUFFER DUAL SUPPLY
INVERTING BUFFER
DUAL SUPPLY
NONINVERTING BUFFER
SINGLE SUPPLY
FOR NONINVERTING BUFFER
SINGLE SUPPLY
3
RES
SHORT
RES
SHORT
OPEN
OPEN
OPEN
OPEN
SHORT
OPEN
SHORT
OPEN
SHORT
OPEN
SHORT
RES
SHORT
RES
R G1
RL3
15
16
17
18
19
20
21
22
SHORT
JP2D
RB3
INV D
HPD/ND
BPD
LPD
SD
NC
CLK
NC
23
24
25
26
27
28
OPEN
JP2C
RH3
INV A
HPA/NA
BPA
LPA
SA
U1
V–
SC
LPC
BPC
HPC/NC
INV C
OPEN
U2A
JP2B
14
13
12
11
NC
V+
AGND
NC
SB
LPB
BPB
HPB/NB
INV B
JP3A
OPEN
SHORT
OPEN
SHORT
RH1
SHORT
JP2A
RL2
RB2
RH2
R23
R33
R43
10
9
8
7
6
5
4
3
R31
R41
2
1
R21
RB1
OPEN
R G2
R51
RL1
BOLD LINE INDICATES FGND
SHORT
R53
C5
10µF
CI1
R11
JPB
FGND LPD
R63
R61
2
1 FGND LPB 3
BUFFERS CONFIGURATION
V+
V–
SINGLE
3 SUPPLY
1 DUAL
SUPPLY
2 JP1
V–
C7
10µF
16V
C6
10µF
16V
R52
RH5
OPEN
SHORT
OPEN
SHORT
SHORT
OPEN
OPEN
OPEN
JP3C
R24
R34
R44
R7 200Ω
U2A
JP3B
R42
R32
R22
DC104 Schematic
RL5
JPC
R62
JP3D
OPEN
OPEN
SHORT
OPEN
2
4
3
2
1
V–
4
3
5
6
7
8
5
6
7
8
5
6
3
2
U2
LT1211
LT1211
LT1213
LT1498
U2B
CO1
V–
4
8
V+
CO2
U2A
U1
LTC1068CG
LTC1068-200CG
LTC1068-25CG
LTC1068-50CG
JP3D
JP3C
JP3B
JP3A
C2
0.1µF
JP2D
JP2C
JP2B
DEMO BOARD
DC104B-A
DC104B-B
DC104B-C
DC104B-D
RL4
RB4
RH4
R64
JPD
3 LPD FGND 1
R54
2
3 LPC FGND 1
RB5
2
1
JP2A
+
–
16
+
–
V+
7
1068 TA03
RG1
C4
0.1µF
1
C3
0.1µF
RG2
E8
SGND
E7
VOUT1
BUFFER 1
E6
SGND
E5
VOUT2
BUFFER 2
LTC1068 Series
APPLICATIONS INFORMATION
1068fc
LTC1068 Series
APPLICATIONS INFORMATION
A Surface Mount Printed Circuit Layout
A very compact surface mount printed circuit layout can
be designed with 0603 size surface mount resistors,
capacitors and a 28-pin SSOP of the LTC1068 product
family. An example of a printed circuit layout is shown
in the following figures for an 8th order elliptic bandpass
filter. The total board area of this 8th order filter is 1" by
0.8". No attempt was made to design the smallest possible
printed circuit layout.
70kHz Elliptic Bandpass Filtter, fCENTER = fCLK/25 (Maximum fCENTER is 80kHz, VS = ±5V)
RH1 28k
RL2 23.2k
RH2 11.3k
1
VIN
R11 29.4k
R21 4.99k
2
R31 24.9k
3
R41 20.5k
R51
4.99k
R61 11.3k
5V
C1
0.1µF
4
5
INV B
INV C
HPB/NB
HPC/NC
BPB
BPC
LPB
LPC
28
27
R22 4.99k
26
R32 107k
25
24
U1
SC
LTC1068-25
6
23
V–
NC
7
22
NC
AGND
8 +
21
CLK
V
9
10
R43 43.2k
11
R33 59k
12
R23 4.99k
13
14
RL3
45.3K
SB
NC
NC
SA
SD
LPA
LPD
BPA
BPD
HPA/NA
INV A
HPD/ND
INV D
20
19
18
17
16
15
R52
4.99k R62 56.2k
–5V
C2
0.1µF
1.75MHz
R64 10k
R54
4.99k
R44 17.4k
R34 63.4k
R24 7.5k
RH3 15.4k
VOUT
1068 TA04
Gain vs Frequency
FilterCAD Custom Inputs for fC = 70kHz
10
2nd ORDER SECTION
f0 (kHz)
Q
fN (kHz)
TYPE
MODE
B
67.7624
5.7236
58.3011
HPN
2b
C
67.0851
20.5500
81.6810
LPN
1bn
–20
81.0295
LPN
2n
–30
BP
2b
73.9324
15.1339
73.3547
16.3491
GAIN (dB)
A
D
0
–10
–40
–50
–60
–70
–80
–90
20
30
40
50 60 70 80
FREQUENCY (kHz)
90
100
1068 TA05
1068fc
17
LTC1068 Series
APPLICATIONS INFORMATION
Surface Mount Components
(Board Area = 1" × 0.8")
RH1
R11
R21
R51
R22
R31
U1
R32
R41
R61
R62
C2
C1
R52
R64
R43
R44
R33
R34
R23
R54
R24
RH2
RL3
RL2
RH3
1068 TA06
Component Side
Solder Side
VIN
RH1
R11
R51 R21
R22
R32 R52
R31
R61
GND
R41
GND
V–
R62
R64
R43
R44
R33
R54
V+
R34
R23
RL3
RH2
RL2
R24
RH3
VOUT
1068 TA07
1068 TA08
1068fc
18
LTC1068 Series
TYPICAL APPLICATIONS
LTC1068-200 8th Order Linear Phase Lowpass, fCUTOFF = fCLK/400
for Ultralow Frequency Applications
RL1
23.2k
VIN
R11
14.3k
R21 12.4k
2
R31 10k
3
R41 15.4k
4
5
7
5V
8
0.1µF
9
10
R43 12.4k
11
R33 12.4k
12
R23 10k
13
14
RL3
23.2k
INV C
HPB/NB
HPC/NC
BPB
BPC
LPB
LPC
SB
NC
LTC1068-200
SC
V–
NC
AGND
V+
CLK
NC
NC
SA
SD
LPA
LPD
BPA
BPD
HPA/NA
INV A
HPD/ND
INV D
28
27
R22 15.4k
26
R32 10k
25
R52 5.11k
Gain and Group Delay
vs Frequency
10
0
R62 9.09k
24
–10
23
–5V
22
0.1µF
21
R64 9.09k
20
19
400kHz
R54 5.11k
18
VOUT
17
R34 10k
16
R24 15.4k
1.0
0.9
GAIN
0.8
–20
0.7
–30
0.6
–40
–50
0.5
GROUP
DELAY
0.4
–60
0.3
–70
0.2
–80
0.1
–90
0.1
1
FREQUENCY (Hz)
15
10
GROUP DELAY (SEC)
6
INV B
GAIN (dB)
1
RL2
14.3k
0
1068 TA10
RB3 23.2k
1068 TA09
FilterCAD Custom Inputs for fC = 1Hz
2nd ORDER SECTION
f0 (kHz)
Q
TYPE
MODE
B
1.7947
0.7347
QN
LP
3
C
1.6002
0.5195
LP
1b
A
1.7961
1.1369
LPBP
3s
D
1.6070
0.5217
LP
1b
1.0159
1068fc
19
LTC1068 Series
TYPICAL APPLICATIONS
LTC1068-50 8th Order Linear Phase Lowpass, fCUTOFF = fCLK/50
for Single Supply Low Power Applications. Maximum fCUTOFF is
20kHz with a 3.3V Supply and 40kHz with a 5V Supply
VIN
R11
22.6k
R31 10k
3
R41 22.6k
4
5
6
7
3.3V
8
0.1µF
9
10
1µF
R43 48.7k
11
R33 12.7k
12
R23 10.7k
13
14
RL3
26.7k
RB1
13.3k
RH2
34k
INV B
INV C
HPB/NB
HPC/NC
BPB
BPC
LPB
SB
NC
LPC
LTC1068-50
V
–
NC
AGND
V
SC
+
CLK
NC
NC
SA
SD
LPA
LPD
BPA
BPD
HPA/NA
HPD/ND
INV A
INV D
Gain and Group Delay
vs Frequency
28
27
R22 43.2k
26
R32 43.2k
25
R42 196k
0
24
23
22
21
500kHz
20
19
R44 34.8k
17
R34 14.3k
16
R24 16.9k
140
GAIN
–10
130
–20
120
–30
110
GROUP
DELAY
–40
100
–50
90
–60
80
–70
70
–80
18
150
10
10
FREQUENCY (kHz)
1
GROUP DELAY (µs)
2
RL2
9.09k
GAIN (dB)
1
R21 20.5k
RA1
56.2k
60
100
1068 TA12
15
RB3 24.9k
VOUT
1068 TA11
FilterCAD Custom Inputs for fC = 10kHz
2nd ORDER SECTION
f0 (kHz)
Q
B
9.5241
0.5248
C
11.0472
1.1258
A
11.0441
1.3392
D
6.9687
0.6082
fN (kHz)
QN
TYPE
MODE
0.5248
AP
4a3
LPN
2n
LPBP
2s
LP
3
21.7724
1.5781
1068fc
20
LTC1068 Series
TYPICAL APPLICATIONS
LTC1068-25 8th Order Lowpass, fCUTOFF = fCLK/32,
Attenuation –50dB at (1.25) (fCUTOFF) and –60dB at
(1.5)(fCUTOFF). Maximum fCUTOFF = 120kHz
RH1 18.2k
RL1
26.7k
RH2 36.5k
VIN
R21 10k
2
R31 10k
3
4
R61
2.21k
R51
4.99k
5
6
7
8
5V
0.1µF
R63 8.45k
9
10
R53
4.99k
11
R33 118k
12
R23 10k
13
14
RL3
20.5K
INV B
INV C
HPB/NB
HPC/NC
BPB
BPC
LPB
LPC
SB
NC
LTC1068-25
SC
V–
NC
AGND
+
V
CLK
NC
NC
SA
SD
LPA
LPD
BPA
BPD
HPA/NA
HPD/ND
INV A
INV D
Gain vs Frequency
28
27
R22 10k
26
R32 32.4k
10
0
25
24
–10
R52
4.99k
–20
R62 5.9k
23
22
–5V
0.1µF
21
20
19
18
GAIN (dB)
1
R11 32.4k
RL2 40.2k
–60
R64 3.16k
–70
R54
4.99k
R34 15k
16
R24 10k
–40
–50
3.2MHz
17
–30
–80
100
FREQUENCY (kHz)
20
500
1069 TA14
15
RH3 53.6k
VOUT
1068 TA13
FilterCAD Custom Inputs for fC = 100kHz
2nd ORDER SECTION
f0 (kHz)
Q
fN (kHz)
TYPE
MODE
B
70.9153
0.5540
127.2678
LPN
1bn
C
94.2154
2.3848
154.1187
LPN
1bn
A
101.4936
9.3564
230.5192
LPN
1bn
D
79.7030
0.9340
LP
1b
1068fc
21
LTC1068 Series
TYPICAL APPLICATIONS
LTC1068 8th Order Linear Phase Bandpass, fCENTER = fCLK/128,
Passband –3dB at (0.88)(fCENTER) and (1.12)(fCENTER). Maximum
fCENTER = 40kHz with ±5V Supplies
RL1
63.4k
RH1
7.5k
R21
4.99k
VIN
R11
26.1k
2
R31
19.6k
3
R41
12.1k
4
5V
0.1µF
HPB/NB
HPC/NC
BPB
BPC
LPB
LPC
9
10
R23
4.99k
11
12
SA
SD
LPA
LPD
BPA
BPD
HPA/NA
INV A
23
R22
4.99k
22
R32
21.5k
HPD/ND
INV D
10
0
–10
–20
21
20
SC
19
V–
CLK
R33
14.7k
RL3
14.7k
INV C
LTC1068
5
SB
6
AGND
7 +
V
8
R43
10.7k
INV B
Gain vs Frequency
24
GAIN(dB)
1
RB2
16.2k
18
R52
4.99k
1.28MHz
15
14
–40
–50
–60
–5V
0.1µF
17
16
R62
7.5k
–30
–70
–80
–90
R64 17.8k
1
R54
4.99k
R34
28.7k
10
FREQUENCY (kHz)
100
1068 TA16
VOUT
R24
4.99k
13
RH3
40.2k
24-Lead Package
1068 TA15
FilterCAD Custom Inputs for fC = 10kHz
2nd ORDER SECTION
f0 (kHz)
Q
fN (kHz)
TYPE
4.4025
HPN
3a
BP
1b
LPN
3a
BP
1b
B
8.2199
2.6702
C
9.9188
3.3388
A
8.7411
2.1125
D
11.3122
5.0830
21.1672
MODE
1068fc
22
LTC1068 Series
TYPICAL APPLICATIONS
LTC1068 8th Order Linear Phase Bandpass, fCENTER = fCLK/100,
Passband –3dB at (0.88)(fCENTER) and (1.12)(fCENTER). Maximum
fCENTER = 50kHz with ±5V Supplies
RL1
24.9k
RB2
14.3k
RH1
51.1k
VIN
R11
24.3k
2
R31
25.5k
3
R41
107k
4
5
0.1µF
8
R43
16.9k
HPB/NB
INV C
HPC/NC
BPB
BPC
LPB
LPC
SB
SC
6
AGND
7 +
V
LTC1068
5V
R63
2.32k
INV B
R53
4.99k
9
R33
17.4k
10
R23
7.32k
11
12
V–
fCLK
SA
SD
LPA
LPD
BPA
BPD
HPA/NA
INV A
HPD/ND
INV D
24
0
23
R22
10k
22
R32
32.4k
21
R42
26.1k
–10
–20
GAIN(dB)
1
R21
10k
Gain vs Frequency
10
20
–40
–50
–60
19
18
–30
–5V
0.1µF
–70
–80
1MHz
–90
17
16
R44
12.1k
15
R34
19.1k
14
R24
10k
1
10
FREQUENCY (kHz)
100
1068 TA18
13
RB3
18.7k
VOUT
24-Lead Package
1068 TA17
FilterCAD Custom Inputs for fC = 10kHz
2nd ORDER SECTION
f0 (kHz)
Q
fN (kHz)
TYPE
MODE
B
10.4569
2.6999
17.4706
LPN
2n
C
11.7607
3.9841
BP
2
A
8.6632
2.1384
BP
2b
D
9.0909
1.8356
BP
3
1068fc
23
LTC1068 Series
TYPICAL APPLICATIONS
LTC1068 8th Order Linear Phase Bandpass, fCENTER = fCLK/100,
Passband –3dB at (0.7)(fCENTER) and (1.3)(fCENTER), Superior Sinewave
Burst Response, Maximum fCENTER = 60kHz with ±5V Supplies
RL1
348k
RL2
10k
RH1
11k
R21
14.7k
VIN
2
R31
10k
R11
11k
3
R41
14.3k
4
INV B
HPB/NB
INV C
HPC/NC
BPB
BPC
LPB
LPC
5
5V
0.1µF
SB
6
AGND
7 +
V
LTC1068
8
R43
21.5k
9
R33
11.3k
10
R23
21k
11
12
SC
SA
SD
LPA
LPD
BPA
BPD
HPA/NA
HPD/ND
INV A
23
R22
18.2k
22
R32
10k
21
R42
18.7k
INV D
0
–10
–20
20
19
V–
fCLK
Gain vs Frequency
10
24
GAIN(dB)
1
RH2
200k
18
–30
–40
–50
–60
–5V
0.1µF
–70
–80
1MHz
17
–90
16
R44
10k
15
R34
17.8k
14
R24
15.4k
10
FREQUENCY (kHz)
1
100
1068 TA20
13
RH3
95.3k
VOUT
24-Lead Package
RL3
12.4k
1068 TA19
FilterCAD Custom Inputs for fC = 10kHz
2nd ORDER SECTION
f0 (kHz)
Q
fN (kHz)
B
10.1389
0.7087
C
9.8654
A
D
QN
TYPE
MODE
1.7779
HPN
3a
0.5540
44.7214
LPN
3a
9.8830
0.5434
27.7227
LPN
3a
12.4097
1.5264
BP
3
1068fc
24
LTC1068 Series
TYPICAL APPLICATIONS
LTC1068-50 8th Order Linear Phase Bandpass, fCENTER = fCLK/40,
Passband –3dB at (0.8)(fCENTER) and (1.2)(fCENTER) for Single Supply
Low Power Applications. Maximum fCENTER = 25kHz with a Single 5V
Supply
RH1 18.2k
RL2 17.8k
RH2 84.5k
VIN
R11 36.5k
R21 10k
2
R31 30.1k
3
R41 10.7k
4
R61
1.74k
R51
4.99k
5
6
7
5V
8
1µF
0.1µF
9
10
R43 12.1k
11
R33 26.7k
12
R23 10k
13
14
RL3
15.8K
INV B
INV C
HPB/NB
HPC/NC
BPB
BPC
LPB
LPC
SB
NC
LTC1068-50
SC
V–
NC
AGND
V+
CLK
NC
NC
SA
SD
LPA
LPD
BPA
BPD
HPA/NA
HPD/ND
INV A
INV D
Gain vs Frequency
28
27
R22 11.3k
10
26
R32 29.4k
0
25
R42 10k
–10
–20
24
GAIN (dB)
1
23
22
21
–30
–40
–50
400kHz
–60
20
–70
19
18
R44 22.1k
17
R34 28k
16
R24 10k
–80
2 4 6 8 10 12 14 16 18 20 22 24 26 28
FREQUENCY (kHz)
1068 TA22
15
RH3 47.5k
VOUT
1068 TA21
FilterCAD Custom Inputs for fC = 10kHz
2nd ORDER SECTION
f0 (kHz)
Q
fN (kHz)
TYPE
MODE
B
8.7384
4.0091
4.0678
HPN
2b
C
11.6756
4.6752
19.1786
LPN
2n
A
10.8117
4.2066
16.0127
LPN
2n
D
9.6415
3.6831
BP
2
1068fc
25
LTC1068 Series
TYPICAL APPLICATIONS
LTC1068-25 8th Order Order Bandpass, fCENTER = fCLK/32,
Passband –3dB at (0.965)(fCENTER) and (1.35)(fCENTER).
Maximum fCENTER = 80kHz with ±5V Supplies
RH1 118k
VIN
R11 121k
R31 97.6k
2
3
4
R61
8.87k
R51
4.99k
5
6
7
8
5V
0.1µF
R63 6.49k
9
10
R53
4.99k
11
R33 124k
12
R23 4.99k
13
14
RL3
78.7K
INV B
HPB/NB
INV C
HPC/NC
BPB
BPC
LPB
LPC
SB
SC
NC
LTC1068-25
V–
NC
AGND
V+
CLK
NC
NC
SA
SD
LPA
LPD
BPA
HPA/NA
INV A
BPD
HPD/ND
INV D
28
27
Gain vs Frequency
R22 4.99k
10
R32 130k
26
0
25
24
R52
4.99k
–10
R62 9.53k
23
22
–5V
0.1µF
21
20
19
18
GAIN (dB)
1
R21 4.99k
RB2 47.5k
320kHz
16
R24 4.99k
–40
–60
R54
4.99k
17
–30
–50
R64 6.98k
R34 102k
–20
–70
7.5
8
8.5
9 9.5 10 10.5 11 11.5 12 12.5
FREQUENCY (kHz)
1068 TA24
15
VOUT
1068 TA23
FilterCAD Custom Inputs for fC = 10kHz
2nd ORDER SECTION
f0 (kHz)
Q
TYPE
MODE
B
10.2398
15.6469
BP
1b
C
10.3699
21.1060
BP
1b
A
9.6241
18.6841
LP
1b
D
9.7744
15.6092
LP
1b
1068fc
26
LTC1068 Series
TYPICAL APPLICATIONS
LTC1068-200 8th Order Highpass, fCENTER = fCLK/200,
Attenuation –60dB at (0.6)(fCENTER).
Maximum fCUTOFF = 20kHz with ±5V Supplies
RH1 11.8k
RL1
66.5k
RH2 20.5k
VIN
R21 10k
2
R31 16.5k
3
R41 11.3k
4
5
5V
R63 2.55k
0.1µF
R53
R43 20.5k 4.99k
R33 36.5k
R23 10k
INV B
INV C
HPB/NB
HPB/NC
BPB
BPC
LPB
LPC
27
R22 21.5k
26
R32 10.2k
0
25
R42 18.7k
–10
10
11
12
13
14
10
–20
24
SC
LTC1068-200 – 23
6
V
NC
7
22
NC
AGND
8 +
21
CLK
V
9
Gain vs Frequency
28
SB
NC
NC
SA
SD
LPA
LPD
BPA
BPD
HPA/NA
INV A
HPD
INV D
GAIN (dB)
1
R11 18.2k
RL2 249k
–5V
0.1µF
–30
–40
–50
200kHz
20
–60
19
–70
–80
0.2
18
R44 21k
17
R34 14.3k
16
R24 20.5k
1
FREQUENCY (kHz)
10
1068 TA26
15
RH3 10k
VOUT
C23 [1/(2π • R23 • C23) = (160)(fCUTOFF)]
1068 TA25
FilterCAD Custom Inputs for fC = 1kHz
2nd ORDER SECTION
f0 (kHz)
Q
fN (kHz)
TYPE
MODE
B
0.9407
1.5964
0.4212
HPN
3a
C
1.0723
0.5156
0.2869
HPN
3a
A
0.9088
3.4293
0.5815
HPN
2b
D
0.9880
0.7001
0.0000
HP
3
1068fc
27
LTC1068 Series
PACKAGE DESCRIPTION
Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings.
G Package
28-Lead Plastic SSOP (5.3mm)
(Reference LTC DWG # 05-08-1640)
9.90 – 10.50*
(.390 – .413)
28 27 26 25 24 23 22 21 20 19 18 17 16 15
1.25 ±0.12
7.8 – 8.2
5.3 – 5.7
0.42 ±0.03
7.40 – 8.20
(.291 – .323)
0.65 BSC
1 2 3 4 5 6 7 8 9 10 11 12 13 14
RECOMMENDED SOLDER PAD LAYOUT
2.0
(.079)
MAX
5.00 – 5.60**
(.197 – .221)
0° – 8°
0.09 – 0.25
(.0035 – .010)
0.65
(.0256)
BSC
0.55 – 0.95
(.022 – .037)
0.05
(.002)
MIN
0.22 – 0.38
(.009 – .015)
TYP
NOTE:
1. CONTROLLING DIMENSION: MILLIMETERS
MILLIMETERS
2. DIMENSIONS ARE IN
(INCHES)
G28 SSOP 0204
3. DRAWING NOT TO SCALE
*DIMENSIONS DO NOT INCLUDE MOLD FLASH. MOLD FLASH
SHALL NOT EXCEED .152mm (.006") PER SIDE
**DIMENSIONS DO NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED .254mm (.010") PER SIDE
N Package
24-Lead PDIP (Narrow .300 Inch)
(Reference LTC DWG # 05-08-1510 Rev I)
1.280*
(32.512)
MAX
24
23
22
21
20
19
18
17
16
15
14
13
1
2
3
4
5
6
7
8
9
10
11
12
.255 ±.015*
(6.477 ±0.381)
.300 – .325
(7.620 – 8.255)
.130 ±.005
(3.302 ±0.127)
.045 – .065
(1.143 – 1.651)
.020
(0.508)
MIN
.008 – .015
(0.203 – 0.381)
(
+.035
.325 –.015
8.255
+0.889
–0.381
)
.120
(3.048)
MIN
.065
(1.651)
TYP
N24 REV I 0711
.100
(2.54)
BSC
.018 ±.003
(0.457 ±0.076)
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)
1068fc
28
LTC1068 Series
REVISION HISTORY
(Revision history begins at Rev C)
REV
DATE
DESCRIPTION
PAGE NUMBER
C
10/12
Correction to Electrical Characteristics table to identify characteristics of LTC1068-50
5
1068fc
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.
29
LTC1068 Series
TYPICAL APPLICATION
LTC1068-200 8th Order Notch, fNOTCH = fCLK/256, f – 3dB at (0.9) (fNOTCH) and (1.05)(fNOTCH),
Attenuation at fNOTCH Greater Than 70dB for fNOTCH in the Frequency Range 200Hz to 5kHz
C22 470pF
RH1 5.11k
VIN
R11 51.1k
C21
470pF
1
R21 5.11k
2
R31 51.1k
3
RH2 5.11k
R41 100k
4
R51
5.11k
R61
8.06k
5
6
7
8
5V
0.1µF
R63
8.06k
9
10
R43
178k
R53
5.11k
11
12
R33 124k
R23 10k
13
14
C23 470pF
INV B
INV C
HPB/NB
HPB/NC
BPB
BPC
LPB
LPC
SB
SC
NC
LTC1068-200
V–
NC
AGND
V+
CLK
NC
NC
SA
SD
LPA
LPD
BPA
BPD
HPA/NA
HPD
INV A
INV D
28
27
R22 6.34k
26
R32 84.3k
25
RL2 66.5k
R62 5.76k
R52
5.11k
24
23
–5V
0.1µF
22
21
fCLK = (256)(fNOTCH)
20
R64 7.87k
19
R54
5.11k
18
17
R34 75k
16
R24 7.32k
RG
15k
15
RH4 5.11k
RH3 5.11k
–
RL4 475k
+
LT1354
VOUT
1068 TA27
Gain vs Frequency
10
0
–10
GAIN (dB)
–20
–30
–40
–50
–60
–70
–80
–90
0.8
1.0
1.1
1.2
0.9
RELATIVE FREQUENCY (fIN/fNOTCH)
1068 TA28
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LTC1064
Universal Filter, Quad 2nd Order
50:1 and 100:1 Clock-to-fO Ratios, fO to 100kHz, VS = Up to ± 7.5V
LTC1067/LTC1067-50
Low Power, Dual 2nd Order
Rail-to-Rail, VS = 3V to ±5V
LTC1164
Low Power Universal Filter, Quad 2nd Order
50:1 and 100:1 Clock-to-fO Ratios, fO to 20kHz, VS = Up to ±7.5V
LTC1264
High Speed Universal Filter, Quad 2nd Order
20:1 Clock-to-fO Ratio, fO to 200kHz, VS = Up to ±7.5V
1068fc
30 Linear Technology Corporation
LT 1012 REV C • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507
●
www.linear.com
 LINEAR TECHNOLOGY CORPORATION 1996