LTC1060ACN#PBF [Linear]
LTC1060 - Universal Dual Filter Building Block; Package: PDIP; Pins: 20; Temperature Range: 0°C to 70°C;
| 型号： | LTC1060ACN#PBF |
| 厂家： | 
Linear |
| 描述： | LTC1060 - Universal Dual Filter Building Block; Package: PDIP; Pins: 20; Temperature Range: 0°C to 70°C LTE 光电二极管 有源滤波器 |
| 文件： | 总20页 (文件大小：260K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
LTC1060
Universal Dual Filter
Building Block
U
FEATURES
DESCRIPTIO
TheLTC®1060consistsoftwohighperformance,switched
capacitor filters. Each filter, together with 2 to 5 resistors,
can produce various 2nd order filter functions such as
lowpass, bandpass, highpass notch and allpass. The
center frequency of these functions can be tuned by an
externalclockorbyanexternalclockandresistorratio. Up
■
Guaranteed Filter Specification for ±2.37V and
±5V Supply
■
Operates Up to 30kHz
■
Low Power and 88dB Dynamic Range at ±2.5V Supply
Center Frequency Q Product Up to 1.6MHz
Guaranteed Offset Voltages
Guaranteed Clock-to-Center Frequency Accuracy Over to 4th order full biquadratic functions can be achieved by
Temperature:
0.3% for LTC1060A
0.8% for LTC1060
Guaranteed Q Accuracy Over Temperature
Low Temperature Coefficient of Q and Center
Frequency
Low Crosstalk, 70dB
Clock Inputs TTL and CMOS Compatible
■
■
■
cascading the two filter blocks. Any of the classical filter
configurations(likeButterworth,Chebyshev,Bessel,Cauer)
can be formed.
■
■
The LTC1060 operates with either a single or dual supply
from ±2.37V to ±8V. When used with low supply
(i.e. single5Vsupply), thefiltertypicallyconsumes12mW
and can operate with center frequencies up to 10kHz. With
±5V supply, the frequency range extends to 30kHz and
very high Q values can also be obtained.
■
■
U
APPLICATIO S
The LTC1060 is manufactured by using Linear
Technology’s enhanced LTCMOS™ silicon gate process.
Because of this, low offsets, high dynamic range, high
center frequency Q product and excellent temperature
stability are obtained.
■
Single 5V Supply Medium Frequency Filters
■
Very High Q and High Dynamic Range Bandpass,
Notch Filters
■
Tracking Filters
■
Telecom Filters
The LTC1060 is pinout compatible with MF10.
, LTC and LT are registered trademarks of Linear Technology Corporation.
LTCMOS trademark of Linear Technology Corporation.
U
TYPICAL APPLICATIO
Single 5V, Gain of 1000 4th Order Bandpass Filter
Amplitude Response
70
3.16k
OUTPUT
60
50
40
30
20
10
0
1
2
20
19
18
17
16
15
14
13
12
11
100k
2k
100k
2k
3.16k
3
V
IN
1mV(RMS)
5V
1k
4
5
0.1µF
LTC1060
6
7
5V
1k
8
9
–10
0
100 125 150 175 200 225 250 275
INPUT FREQUENCY (Hz)
LTC1060 • TA02
10
CLOCK IN
17.5kHz
LTC1060 • TA01
1060fb
1
LTC1060
W W U W
U W
U
ABSOLUTE AXI U RATI GS
PACKAGE/ORDER I FOR ATIO
(Note 1)
TOP VIEW
ORDER PART
NUMBER
Supply Voltage ........................................................ 18V
Power Dissipation.............................................. 500mW
Operating Temperature Range
LTC1060AC/LTC1060C................ –40°C ≤ TA ≤ 85°C
LTC1060AM/LTC1060M ............ –55°C ≤ TA ≤ 125°C
Storage Temperature Range ................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
1
2
LP
B
20
19
18
17
16
15
14
13
12
11
LP
A
BP
A
A
A
BP
B
LTC1060ACN
LTC1060CN
LTC1060CSW
3
N/AP/HP
N/AP/HP
INV
B
4
INV
B
5
S1B
S1A
6
AGND
–
S
A/B
+
7
V
A
V
A
–
+
8
V
D
V
D
9
50/100/HOLD
CLKB
LSh
10
CLKA
N PACKAGE
20-LEAD PDIP
SW PACKAGE
20-LEAD PLASTIC SO WIDE
T
= 100°C, θ = 100°C/W (N)
JMAX
JMAX
JA
T
= 150°C, θ = 80°C/W (SW)
JA
J PACKAGE
LTC1060ACJ
LTC1060MJ
LTC1060AMJ
LTC1060CJ
20-LEAD CERDIP
= 150°C, θ = 70°C/W
T
JMAX
JA
OBSOLETE PACKAGE
Consider the N20 and SW20 Package for Alternate Source
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS
The ■ denotes specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. (Complete Filter) Vs = ±5V, unless otherwise noted.
PARAMETER
Center Frequency Range
(See Applications Information)
CONDITIONS
f • Q ≤ 400kHz, Mode 1, Figure 4
MIN
TYP
0.1 to 20k
0.1 to 16k
MAX
UNITS
Hz
Hz
0
f • Q ≤ 1.6MHz, Mode 1, Figure 4
0
Clock-to-Center Frequency Ratio
LTC1060A
Mode 1, 50:1, f
Mode 1, 50:1, f
= 250kHz, Q = 10
= 250kHz, Q = 10
CLK
CLK
■
■
■
■
50 ± 0.3%
50 ± 0.8%
100 ± 0.3%
100 ± 0.8%
CLK
CLK
LTC1060
LTC1060A
LTC1060
Mode 1, 100:1, f
Mode 1, 100:1, f
= 500kHz, Q = 10
= 500kHz, Q = 10
Q Accuracy
LTC1060A
LTC1060
Mode 1, 50:1 or 100:1, f = 5kHz, Q=10
■
■
±0.5
±0.5
3
5
%
%
0
Mode 1, 50:1 or 100:1, f = 5kHz, Q=10
0
f Temperature Coefficient
Q Temperature Coefficient
Mode 1, f
Mode 1, f
< 500kHz
< 500kHz, Q = 10
–10
20
ppm/°c
ppm/°c
0
CLK
CLK
DC Offset V
■
■
■
■
■
■
■
2
3
6
2
4
2
4
15
40
80
30
60
30
60
mV
mV
mV
mV
mV
mV
mV
OS1
OS2
OS2
OS2
OS2
OS3
OS3
V
V
V
V
V
V
f
f
f
f
f
f
= 250kHz, 50:1, S = High
A/B
CLK
CLK
CLK
CLK
CLK
CLK
= 500kHz, 100:1, S = High
A/B
= 250kHz, 50:1, S = Low
A/B
= 500kHz, 100:1, S = Low
A/B
= 250kHz, 50:1, S = Low
A/B
= 500kHz, 100:1, S = Low
A/B
DC Lowpass Gain Accuracy
Mode 1, R1 = R2 = 50k
Mode 1, Q = 10, f = 5kHz
±0.1
±0.1
10
1.5
5
2
%
%
BP Gain Accuracy at f
Clock Feedthrough
Max Clock Frequency
0
0
f
≤ 1MHz
mV
(P-P)
CLK
MHz
mA
mA
Power Supply Current
3
8
12
■
Crosstalk
70
dB
1060fb
2
LTC1060
ELECTRICAL CHARACTERISTICS The ■ denotes specifications which apply over the full operating temperature
range, otherwise specifications are at TA = 25°C. (Complete Filter) VS = ±2.37V.
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Center Frequency Range
f • Q ≤ 100kHz
0
0.1 to 10k
Hz
Clock-to-Center Frequency Ratio
LTC1060A
Mode 1, 50:1, f
Mode 1, 50:1, f
Mode 1, 100:1, f
Mode 1, 100:1, f
= 250kHz, Q = 10
= 250kHz, Q = 10
■
■
50 ± 0.5%
CLK
CLK
LTC1060
LTC1060A
LTC1060
50 ± 0.8%
100 ± 0.5%
100 ± 0.8%
= 250kHz, Q = 10
= 250kHz, Q = 10
CLK
CLK
Q Accuracy
LTC1060A
LTC1060
Mode1, 50:1 or 100:1, f = 2.5kHz, Q = 10
±2
±4
%
%
0
Mode1, 50:1 or 100:1, f = 2.5kHz, Q = 10
0
Max Clock Frequency
Power Supply Current
500
2.5
kHz
mA
4
The ■ denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C.
(Internal Op Amps).
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Supply Voltage Range
±2.37
±8
V
Voltage Swings
LTC1060A
±4
±3.8
±3.6
±4
±4
±4
V
V
V
LTC01060
LTC01060, LTC01060A
V = ±5V,R = 5k (Pins 1,2,19,20)
S
L
R = 3.5k (Pins 3,18)
L
■
Output Short-Circuit Current
V = ±5V
S
Source
Sink
25
3
mA
mA
Op Amp GBW Product
Op Amp Slew Rate
V = ±5V
2
7
85
MHz
V/µs
dB
S
V = ±5V
S
Op Amp DC Open Loop Gain
R = 10k, V = ±5V
L
S
Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired.
W
BLOCK DIAGRA
+
+
V
D
8
V
N/AP/HP S1A
BP
2
LP
1
A
A
A
A
7
3
5
INVA
4
–
–
–
+
∫
∫
∑
+
S
2A
AGND
15
10
LEVEL NON-OVERLAP
CLK
A
SHIFT
CLOCK
12
9
6
S
50/100/HOLD
LEVEL SHIFT
CONTROL
AB
LEVEL NON-OVERLAP
CLK
B
11
SHIFT
CLOCK
TO AGND
S
2B
+
–
–
+
∑
∫
∫
–
INV
17
B
13 14
18
16
19
20
LP
–
–
V
V
A
N/AP/HP S1B
BP
D
B
B
B
LTC1060 • BD01
1060fb
3
LTC1060
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Graph 1. Mode 1:
(fCLK/f0) Deviation vs Q
Graph 2. Mode 1:
(fCLK/f0) Deviation vs Q
Graph 3. Mode 1:
Q Error vs Clock Frequency
V
T
CLK
= ±5V
V
T
CLK
= ±5V
T
= 25°C
V = ±5V
S
f
S
A
S
A
A
CLK
0.4
0
= 100 (TEST POINT)
= 25°C
V = ±2.5V
S
= 25°C
f
50 20 10
0
20
10
Q = 5
f
= 500kHz
10
f
= 250kHz
Q = 5
100
0.1
0
20
50
–0.4
f
CLK
– 0.1
– 0.2
–0.8
–1.2
= 100:1
f
f
0
CLK
0
= 50 (TEST POINT)
f
V
= ±2.5V
V
= ±5V
0
S
S
– 0.3
– 0.4
– 0.5
– 0.6
–1.6
–2.0
–2.4
50 20 10
2010
20
Q = 5
100
Q = 5
f
50
CLK
10
0
= 50:1
f
0
0.1
1
10
100
0.1
1
10
100
0.2 0.4 0.6 0.8
1.2
1.6 1.8 2.0
1.4
1.0
IDEAL Q
f
(MHz)
IDEAL Q
CLK
LT1060 • TPC02
LT1060 • TPC01
LTC1060 • TPC03
Graph 4. Mode 1:
Q Error vs Clock Frequency
Graph 5. Mode 1: Measured Q vs
fCLK and Temperature
Graph 6. Mode 1:
(fCLK/f0) vs fCLK and Q
0.8
0.6
0.4
0.2
V = ±5V
V
T
CLK
= ±7.5V
= 25°C
V = ±5V
85°C
S
S
A
S
Q = 10
T
f
= 25°C
10
50
A
CLK
125°C
20
10
f
100
200
Q = 5
20
0
f
T
= 25°C
CLK
A
= 100:1
= 100:1
= 100:1
f
–55°C
f
f
0
0
0
400
85°C
0
Q = 20
T
= 25°C
A
125°C
Q = 5
Q = 50
100
200
10
f
–55°C
50
20
0
20
CLK
0
–0.2
–0.4
= 50:1
f
CLK
f
0
Q = 10
= 50:1
f
0
10
0
Q = 5
400
–20
1.2 1.4
(MHz)
0.2 0.4 0.6 0.8 1.0
1.6 1.8
0.8
1.2 1.4
0
0.2
0.4 0.6
1.0
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
(MHz)
f
CLK
f
f
(MHz)
CLK
CLK
LTC1060 • TPC05
LTC1060 • TPC06
LTC1060 • TPC04
Graph 7. Mode 1:
(fCLK/f0) vs fCLK and Q
Graph 8. Mode 1: (fCLK/f0) vs fCLK
and Temperature
Graph 9. Mode 1: (fCLK/f0) vs fCLK
and Temperature
0.8
0.6
0.4
0.2
1.0
0.8
0.6
0.4
0.2
0
1.0
0.8
0.6
0.4
0.2
0
V = ±5V
V = ±5V
V = ±5V
85°C
S
S
T
= 25°C
S
A
125°C
T
f
= 25°C
Q = 10
Q = 10
125°C
A
CLK
85°C
f
f
CLK
CLK
f
0
T = 25°C
A
= 50:1
= 100:1
= 50:1
f
f
0
0
Q = 50
Q = 20
Q = 10
–55°C
–55°C
0
–0.2
–0.4
Q = 5
0.2 0.4 0.6
–0.2
–0.2
1.2 1.4
(MHz)
1.2 1.4
(MHz)
0.2 0.4 0.6 0.8 1.0
1.6 1.8
0.2 0.4 0.6 0.8 1.0
1.6 1.8
0.8
1.2 1.4
0
1.0
f
f
CLK
CLK
f
(MHz)
CLK
LTC1060 • TPC09
LTC1060 • TPC08
LTC1060 • TPC07
1060fb
4
LTC1060
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Graph 10. Mode 1:
(fCLK/f0) vs fCLK and Q
Graph 11. Mode 1:
(fCLK/f0) vs fCLK and Q
Graph 12. Mode 1: (fCLK/f0) vs fCLK
and Temperature
1
0.8
0.6
0.4
0.2
0
1.0
0.8
0.6
0.4
0.8
0.6
0.4
0.2
V = ±2.5V
V = ±2.5V
V = ±2.5V
S
S
S
Q = 10
T
f
= 25°C
T
f
= 25°C
A
CLK
A
CLK
–55°C
f
85°C
CLK
= 100:1
= 100:1
= 50:1
f
f
f
0
0
0
T
= 25°C
A
125°C
Q = 50
Q = 20
Q = 10
Q = 20
0.2
0
0
–0.2
–0.4
Q = 50
Q = 10
Q = 5
Q = 5
–0.2
0
0.4
0.6
f (kHz)
CLK
0.8
1.0
1.2
0.2
400
600 700
0
100 200 300
f
500
400
600 700
0
100 200 300
500
(MHz)
f
(MHz)
CLK
CLK
LTC1060 • TPC12
LTC1060 • TPC10
LTC1060 • TPC11
Graph 15. Mode 3: Deviation of
(fCLK/f0) with Respect to Q = 10
Measurement
Graph 13. Mode 1: (fCLK/f0) vs
fCLK and Temperature
Graph 14. Mode 1:
Notch Depth vs Clock Frequency
1.0
0.8
0.6
0.4
0.2
0
120
100
80
60
40
20
0
V = ±5V
V = ±5V
S
S
f
T
= 25°C
CLK
T
= 25°C
A
A
= 500: 1
Q = 10
100:1
–55°C
T
= 25°C
85°C
V
= 1V
f
PIN 12 AT 100:1
RMS
A
IN
O
Q = 1
100:1
R2
R4
1
5
=
0.1
0
(A)
–0.1
125°C
R2
R4
1
2
Q = 10
50:1
–0.2
–0.3
–0.4
–0.5
=
f
CLK
V = ±2.5V
= 200: 1
(B)
S
f
O
Q = 10
f
CLK
= 50:1
f
0
–0.2
1.0 1.2
(MHz)
0
0.2 0.4 0.6 0.8
1.4 1.6
0
0.4
0.6
(kHz)
0.8
1.0
1.2
0.2
0.1
1
10
100
f
f
IDEAL Q
CLK
CLK
LTC1060 • TPC15
LTC1060 • TPC14
LTC1060 • TPC13
Graph 18. Mode 3 (R2 = R4):
Measured Q vs fCLK and
Temperature
Graph 16. Mode 3:
Q Error vs Clock Frequency
Graph 17. Mode 3 (R2 = R4):
Q Error vs Clock Frequency
40
20
0
125°C
V = ±5V
V
= ±2.5V
V = ±5V
S
V
= ±7.5V
= 25°C
S
S
T
f
= 25°C
S
A
A
Q = 10
T
f
50
20 Q = 5 20 10
50
10
T
= 25°C
–55°C
CLK
10
f
20
10
20
Q = 5
A
85°C
CLK
= 100:1
CLK
= 100:1
f
= 100:1
0
f
0
f
0
Q = 5
10
50
V
125°C
= 50:1
–20
40
0
0
f
= ±2.5V
V
= ±5V
S
CLK
S
f
0
10
10
20
T
= 25°C
–55°C
A
Q = 5
20
0
20
20
85°C
Q = 5
50
20
50
10
Q = 5
f
50
f
CLK
10
0
10
0
CLK
= 50:1
= 50:1
f
f
0
0
–20
1.2 1.4
(MHz)
0.2 0.4 0.6 0.8 1.0
1.6 1.8
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
(MHz)
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
(MHz)
f
f
f
CLK
CLK
CLK
LTC1060 • TPC18
LTC1060 • TPC16
LTC1060 • TPC17
1060fb
5
LTC1060
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Graph 19. Mode 3 (R2 = R4):
(fCLK/f0) vs fCLK and Q
Graph 20. Mode 3 (R2 = R4):
(fCLK/f0) vs fCLK and Q
Graph 21. Mode 3 (R2 = R4):
(fCLK/f0) vs fCLK and Temperature
1.0
0.8
0.6
0.4
0.2
0
0.8
0.6
0.4
0.2
0.8
0.6
0.4
0.2
V = ±5V
V = ± 5V
V = ± 5V
S
S
S
T
f
= 25°C
Q = 10
T
f
= 25°C
A
CLK
A
CLK
f
CLK
= 100:1
= 50:1
= 100:1
f
f
f
0
0
0
Q = 20
85°C
125°C
Q = 50
T
= 25°C
–55°C
Q = 10
A
Q = 20, Q = 40, Q = 50
0
–0.2
–0.4
0
–0.2
–0.4
Q = 10
Q = 5
Q = 5
0.2
–0.2
1.2 1.4
(MHz)
0.8
1.2 1.4
0.2 0.4 0.6 0.8 1.0
1.6 1.8
0
0.2
0.4 0.6
1.0
0.8
1.2
1.4
0
0.4 0.6
1.0
f
f
(MHz)
f
(MHz)
CLK
CLK
CLK
LTC1060 • TPC21
LTC1060 • TPC19
LTC1060 • TPC20
Graph 22. Mode 3 (R2 = R4):
(fCLK/f0) vs fCLK and Temperature
Graph 23. Mode 3 (R2 = R4):
(fCLK/f0) vs fCLK and Temperature
Graph 24. Mode 3 (R2 = R4):
(fCLK/f0) vs fCLK and Temperature
1.0
0.8
0.6
0.4
0.2
0
0.8
0.6
1.0
0.8
0.6
0.4
0.2
0
V = ±5V
V = ±2.5V
S
S
–55°C
Q = 10
Q = 10
–55°C
f
f
CLK
CLK
= 100:1
= 100:1
85°C
f
f
T
= 25°C
0
0
A
0.4
T
= 25°C
A
125°C
85°C
85°C
T
= 25°C
125°C
A
125°C
0.2
–55°C
0
V = ±2.5V
S
Q = 10
–0.2
–0.4
f
CLK
= 100:1
f
0
1.2 1.4
0.2 0.4 0.6 0.8
f
1
1.6 1.8
0
0.4
0.6
0.8
1.0
1.2
0
0.4
0.6
(MHz)
0.8
1.0
0.2
0.2
(MHz)
f
f
(MHz)
CLK
CLK
CLK
LTC1060 • TPC22
LTC1060 • TPC23
LTC1060 • TPC24
Graph 25. Mode 1c (R5 = 0),
Mode 2 (R2 = R4) Q Error vs
Clock Frequency
Graph 26.Supply Current vs
Supply Voltage
20
18
16
14
12
10
8
V = ±5V
f
≤ 1MHz
S
A
CLK
Q = 10
20
T
f
= 25°C
20
10
0
CLK 70.7
Q = 20
MODE 2
=
f
1
0
T
= –55°C
A
R2 = R4
T
= 25°C
A
Q = 10
f
20
Q = 20
MODE 2
CLK 35.37
20
10
0
T
= 125°C
f
1
6
A
0
R2 = R4
4
2
0
0.8
1.2 1.4
0
0.2
0.4 0.6
1.0
±1 ±2 ±3 ±4 ±5 ±6 ±7 ±8 ±9 ±10 ±11
SUPPLY VOLTAGE (±V)
f
(MHz)
CLK
LTC1060 • TPC25
LTC1060 • TPC26
1060fb
6
LTC1060
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PIN DESCRIPTION AND APPLICATIONS INFORMATIO
Power Supplies
operation of the device. By tying Pin 12 to 1/2 supplies
(which should be the AGND potential), the LTC1060
operates in the 100:1 mode. The 1/2 supply bias of Pin 12
can vary around the 1/2 supply potential without affecting
the 100:1 filter operation. This is shown in Table 1.
The V+ and V+ (pins 7 and 8) and the V– and V–
A
D
(Pins 14 and 13)Dare, respectively, the analog Aand digital
positive and negative supply pins. For most cases, Pins 7
and8shouldbetiedtogetherandbypassedbya0.1µFdisc
ceramic capacitor. The same holds for Pins 13 and 14. If
the LTC1060 operates in a high digital noise environment,
the supply pins can be bypassed separately. Pins 7 and 8
are internally connected through the IC substrate and
should be biased from the same DC source. Pins 13 and
14 should also be biased from the same DC source.
WhenPin12isshortedtothenegativesupplypin, thefilter
operation is stopped and the bandpass and lowpass
outputs act as a S/H circuit holding the last sample. The
hold step is 20mV and the droop rate is 150µV/second!
Table 1
VOLTAGE RANGE OF PIN 12
The LTC1060 is designed to operate with ±2.5V supply
(or single 5V) and with ±5V to ±8V supplies. The mini-
mum supply, where the filter operates reliably, is ±2.37V.
With low supply operation, the maximum input clock
frequency is about 500kHz. Beyond this, the device exhib-
its excessive Q enhancement and center frequency errors.
TOTAL POWER SUPPLY
FOR 100:1 OPERATION
5V
2.5 ± 0.5V
10V
15V
5V ± 1V
7.5V ± 1.5V
S1A, S1B (Pins 5 and 16)
Clock Input Pins and Level Shift
These are voltage signal input pins and, if used, they
shouldbedrivenwithasourceimpedancebelow5kΩ. The
S1A, S1B pins can be used to alter the CLK to center
frequency ratio (fCLK/f0) of the filter (see Modes 1b, 1c, 2a,
2b) or to feedforward the input signal for allpass filter
configurations (see Modes 4 and 5). When these pins are
not used, they should be tied to the AGND pin.
The level shift (LSh) Pin 9 is used to accommodate T2L or
CMOS clock levels. With dual supplies equal or higher
to ±4.5V, Pin 9 should be connected to ground (same
potential as the AGND pin). Under these conditions the
clock levels can be T2L or CMOS. With single supply
operation, thenegativesupplypinsandtheLShpinshould
be tied to the system ground. The AGND, Pin 15, should
be biased at 1/2 supplies, as shown in the “Single 5V Gain
of 1000 4th Order Bandpass Filter” circuit. Again, under
theseconditions, theclocklevelscanbeT2LorCMOS. The
input clock pins (10,11) share the same level shift pin.
The clock logic threshold level over temperature is
typically 1.5V ±0.1V above the LSh pin potential. The duty
cycle of the input clock should be close to 50%. For clock
frequenciesbelow1MHz, the(fCLK/f0)ratioisindependent
from the clock input levels and from its rise and fall times.
Fast rising clock edges, however, improve the filter DC
offsets. For clock frequencies above 1MHz, T2L level
clocks are recommended.
SA/B (Pin 6)
When SA/B is high, the S2 input of the filter’s voltage
summer(seeBlockDiagram)istiedtothelowpassoutput.
This frees the S1 pin to realize various modes of operation
for improved applications flexibility. When the SA/B pin is
connected to the negative supply, the S2 input switches to
ground and internally becomes inactive. This improves
the filter noise performance and typically lowers the value
of the offset VOS2
.
AGND (Pln 15)
This should be connected to the system ground for dual
supply operation. When the LTC1060 operates with a
single positive supply, the analog ground pin should be
tied to 1/2 supply and bypassed with a 0.1µF capacitor, as
shown in the application, “Single 5V, Gain of 1000 4th
Order Bandpass Filter.” The positive inputs of all the
1060fb
50/100/Hold (Pin 12)
By tying Pin 12 to (V+A and V +D), the filter operates in the
50:1 mode. With ±5V supplies, Pin 12 can be typically 1V
below the positive supply without affecting the 50:1
7
LTC1060
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APPLICATIO S I FOR ATIO
internal op amps, as well as the reference point of all the
internal switches are connected to the AGND pin. Because
of this, a “clean” ground is recommended.
clock-to-center frequency is lowered below 50:1. In mode
1c with R6 = 0 and R6 = ∞, the (fCLK/f0) ratio is 50/√2. The
f0 x Q product can now be increased to 9MHz since, with
the same clock frequency and same Q value, the filter can
handle a center frequency of 16kHz x √2.
fCLK/f0 Ratio
The fCLK/f0 reference of 100:1 or 50:1 is derived from the
filter center frequency measured in mode 1, with a Q = 10
and VS = ±5V. The clock frequencies are, respectively,
500kHz/250kHz for the 100:1/150:1 measurement. All the
curves shown in the Typical Performance Characteristics
section are normalized to the above references.
For clock frequencies above 1MHz, the f0 x Q product is
limited by the clock frequency itself. From Graph 4 at
±7.5V supply, 50:1 and 1.4MHz clock, a Q of 5 has about
8% error; the measured 28kHz center frequency was
skewed by 0.8% with respect to the guaranteed value at
250kHz clock. Under these conditions, the f0 x Q product
is only 140kHz but the filter can handle higher input signal
frequencies than the 800kHz clock frequency, very high Q
case described above.
Graphs 1 and 2 in the Typical Performance Characteristics
show the (fCLK/f0) variation versus values of ideal Q. The
LTC1060 is a sampled data filter and it only approximates
continuous time filters. In this data sheet, the LTC1060 is
treated in the frequency domain because this approxima-
tion is good enough for most filter applications. The
LTC1060 deviates from its ideal continuous filter model
when the (fCLK/f0) ratio decreases and when the Q’s are
low. Since low Q filters are not selective, the frequency
domain approximation is well justified. In Graph 15 the
LTC1060 is connected in mode 3 and its ( fCLK/f0) ratio is
adjusted to 200:1 and 500:1. Under these conditions, the
filter is over-sampled and the (fCLK/f0) curves are nearly
independent of the Q values. In mode 3, the ( fCLK/f0) ratio
typicallydeviatesfromthetestedoneinmode1by±0.1%.
Mode 3, Figure 11, and the modes of operation where R4
is finite, are “slower” than the basic mode 1. This is shown
in Graph 16 and 17. The resistor R4 places the input op
amp inside the resonant loop. The finite GBW of this op
amp creates an additional phase shift and enhances the Q
value at high clock frequencies. Graph 16 was drawn with
a small capacitor, CC, placed across R4 and as such, at VS
= ±5V, the (1/2πR4CC) = 2MHz. With VS = ±2.5V the (1/
2πR4CC) should be equal to 1.4MHz. This allows the Q
curve to be slightly “flatter” over a wider range of clock
frequencies. If, at ±5V supply, the clock is below 900kHz
(or 400kHz for VS = ±2.5V), this capacitor, CC, is not needed.
For Graph 25, the clock-to-center frequency ratios are
altered to 70.7:1 and 35.35:1. This is done by using mode
1c with R5 = 0, Figure 7, or mode 2 with R2 = R4 = 10kΩ.
The mode 1c, where the input op amp is outside the main
loop, is much faster. Mode 2, however, is more versatile.
At 50:1, and for TA = 25°C the mode 1c can be tuned for
center frequencies up to 30kHz.
f0 x Q Product Ratio
This is a figure of merit of general purpose active filter
building blocks. The f0 x Q product of the LTC1060
depends on the clock frequency, the power supply volt-
ages, the junction temperature and the mode of operation.
At 25°C ambient temperature for ±5V supplies, and
for clock frequencies below 1MHz, in mode 1 and its
derivatives, the f0 x Q product is mainly limited by the
desired f0 and Q accuracy. For instance,from
Graph 4 at 50:1 and for fCLK below 800kHz, a predictable
ideal Q of 400 can be obtained. Under this condition, a
respectable f0 x Q product of 6.4MHz is achieved. The
16kHz center frequency will be about 0.22% off from the
tested value at 250kHz clock (see Graph 1). For the same
clock frequency of 800kHz and for the same Q value of
400, the f0 x Q product can be further increased if the
Output Noise
ThewidebandRMSnoiseoftheLTC1060outputsisnearly
independent from the clock frequency, provided that the
clockitselfdoesnotbecomepartofthenoise.TheLTC1060
noise slightly decreases with ±2.5V supply. The noise at
the BP and LP outputs increases for high Q’s. Table 2
shows typical values of wideband RMS noise. The num-
bers in parentheses are the noise measurement in mode 1
with the SA/B pin shorted to V– as shown in Figure 25.
1060fb
8
LTC1060
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APPLICATIO S I FOR ATIO
U
Table 2. Wideband RMS Noise
f
NOTCH/HP
(µV
BP
(µV
LP
(µV
CLK
V
f
)
)
)
CONDITIONS
S
0
RMS
RMS
RMS
±5V
±5V
±2.5V
±2.5V
50:1
100:1
50:1
49 (42)
70 (55)
33 (31)
48 (40)
52 (43)
80 (58)
36 (32)
52 (40)
75 (65)
90 (88)
48 (43)
66 (55)
Mode1, R1 = R2 = R3
Q = 1
100:1
±5V
±5V
±2.5V
±2.5V
50:1
100:1
50:1
20 (18)
25 (21)
16 (15)
20 (17)
150 (125)
220 (160)
100 (80)
186 (155)
240 (180)
106 (87)
Mode 1, Q = 10
R1 = R3 for BP out
R1 = R2 for LP out
100.1
150 (105)
150 (119)
±5V
±5V
±2.5V
±2.5V
50:1
100:1
50:1
57
72
40
50
57
72
40
50
62
80
42
53
Mode 3, R1 = R2 = R3 = R4
Q = 1
100.1
±5V
±5V
±2.5V
±2.5V
50:1
100:1
50:1
135
170
100
125
120
160
88
140
185
100
130
Mode 3, R2 = R4, Q = 10
R3 = R1 for BP out
R4 = R1 for LP and HP out
100:1
115
Short-Circuit Currents
Shortcircuitstoground,positiveornegativepowersupply
are allowed as long as the power supplies do not exceed
±5V and the ambient temperature stays below 85˚C.
Above ±5V and at elevated temperatures, continuous
short circuits to the negative power supply will cause
excessive currents to flow. Under these conditions, the
device will get damaged if the short-circuit current is
allowed to exceed 80mA.
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DEFINITION OF FILTER FUNCTIONS
Each building block of the LTC1060, together with an
external clock and a few resistors, closely approximates
2ndorderfilterfunctions. Thesearetabulatedbelowinthe
frequency domain.
Q = Quality factor of the complex pole pair. It is the
ratio of f0 to the –3dB bandwidth of the 2nd or-
der bandpass function. The Q is always mea-
sured at the filter BP output.
1. Bandpass function: available at the bandpass output
2. Lowpass function: available at the LP output Pins
Pins 2 (19). (Figure 1.)
1 (20). (Figure 2.)
ω2o
G(s) = HOLP
sωo/Q
s2 + (sωo/Q) + ωo
G(s) = HOBP
2
s2 + s(ωo/Q) + ω2o
HOBP = Gain at ω = ωo
HOLP DC gain of the LP output.
f0 = ω/2π; f0 is the center frequency of the complex
pole pair. At this frequency, the phase shift
between input and output is –180˚.
1060fb
9
LTC1060
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DEFINITION OF FILTER FUNCTIONS
3. Highpass function: available only in mode 3 at the
5. Allpassfunction:availableatPins3(18)formode4,4a.
ouput Pins 3 (18). (Figure 3.)
[s2 – s(ωo/Q) + ω2o]
s2 + s(ωo/Q) + ω2o
s2
G(s) = HOAP
G(s) = HOHP
s2 + s(ωo/Q) + ω2o
fCLK
fCLK
2
HOAP = gain of the allpass output for 0 <f<
2
HOHP = gain of the HP output for f→
For allpass functions, the center frequency and the Q of
the numerator complex zero pair is the same as the
denominator. Under these conditions, the magnitude
responseisastraightline. Inmode5, thecenterfrequency
fz, of the numerator complex zero pair, is different than f0.
For high numerator Q’s, the magnitude response will have
a notch at fz.
4. Notch function: available at Pins 3 (18) for several
modes of operation.
+
s2 ω2
o
G(s) = (HON2
)
s2 + (sωo/Q) + ω2o
fCLK
2
HON2 = gain of the notch output for f→
HON1 = gain of the notch output for f→0
fn=ωn/2π;fnisthefrequencyofthenotchoccurrence.
HIGHPASS OUTPUT
H
OP
LOWPASS OUTPUT
H
OHP
0.707 H
H
BANDPASS OUTPUT
OP
OHP
H
OLP
H
OBP
0.707 H
OLP
0.707 H
OBP
f
f
P
C
f(LOG SCALE)
f
P
f
C
f
f f
0 H
L
f(LOG SCALE)
– 1
f(LOG SCALE)
1
1
f
= f
•
•
1 –
+
1 –
2+ 1
C
0
2Q2
2Q2
(
(
(
(
1
1
2+ 1
f
0
f
= f
•
0
1 –
+
1 –
C
Q =
2Q2
2Q2
; f
0
=
f
L
f
(
(
(
(
H
f
– f
H
L
– 1
1
f
= f
1 –
P
0
2Q2
1
–1
20
1
2Q
f
= f
1 –
P
0
f
L
= f
+
2+ 1
2Q2
0
0
(
(
(
(
)
)
1
H
= H
•
OHP
1
OP
H = H
OP OLP
•
1
2Q
1
2Q
f
= f
+
2+ 1
1
Q
1
H
1
Q
1
(
(
1 –
1 –
4Q2
4Q2
TLC1060 • DFF03
TLC1060 • DFF01
TLC1060 • DFF02
Figure 1
Figure 2
Figure 3
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ODES OF OPERATIO
Table 3. Modes of Operation: 1st Order Functions
MODE
PIN 2 (19)
PIN 3 (18)
f
f
C
Z
6a
LP
HP
f
R2
CLK
•
100(50) R3
6b
7
LP
LP
LP
AP
f
CLK
100(50) R3
R2
•
f
R2
f
R2
CLK
CLK
•
•
100(50) R3
100(50) R3
1060fb
10
LTC1060
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Table 4. Modes of Operation: 2nd Order Functions
MODE
PIN 1 (20)
PIN 2 (19)
PIN 3 (18)
f
f
n
0
1
LP
BP
Notch
f
CLK
100(50)
1a
1b
1c
2
LP
LP
LP
LP
BP
BP
BP
BP
BP
f
CLK
100(50)
Notch
Notch
Notch
f
R6
R5 + R6
f
R6
R5 + R6
CLK
CLK
•
•
100(50)
100(50)
f
R6
R5 + R6
f
R6
R5 + R6
CLK
CLK
•
1 +
1 +
•
1 +
100(50)
100(50)
f
f
R2
R4
CLK
CLK
•
•
100(50)
100(50)
2a
2b
3
LP
LP
LP
LP
LP
BP
BP
BP
BP
BP
Notch
Notch
HP
f
R6
R5 + R6
f
R2
R6
CLK
CLK
•
1 +
1 +
+
100(50)
100(50)
R4 R5 + R6
f
R6
R5 + R6
f
R2
R6
+
CLK
CLK
•
•
•
100(50)
100(50)
R4 R5 + R6
f
R2
R4
CLK
100(50)
3a
4
Notch
AP
f
R
h
f
R2
R4
CLK
CLK
•
•
100(50)
R
I
100(50)
f
CLK
100(50)
4a
5
LP
LP
BP
BP
AP
CZ
f
R2
R4
CLK
•
•
100(50)
f
R2
1 +
f
R1
1 –
CLK
CLK
•
100(50)
R4
100(50)
R4
V
IN
R3
R2
R3
R2
BP2
(18)
S1A
(16)
BP1
(19)
LP
(20)
N
(18)
S1A
(16)
BP
(19)
LP
(20)
2
1
2
1
3
5
3
5
R1
–
V
IN
4
–
+
4
–
+
–
+
+
(17)
(17)
Σ
∫
∫
∫
∫
Σ
–
–
S
A/B
S
A/B
TLC1060 • MOO02
TLC1060 • MOO01
1/2 LTC1060
1/2 LTC1060
6
15
6
15
=
+
+
V
V
f
f
R3
R2
R3
CLK
R2
R1
R3
R1
R2
R1
R3
R2
CLK
100(50)
f =
0
; Q =
; H
OBP1
= –
; H
= 1(NON-INVERTING) H
OLP
= – 1
f
; f = f ; H
=
; H = –
OBP
; H
ON1
= –
; Q =
OBP2
0
n
0
OLP
R2
100(50)
Figure 4. Mode 1: 2nd Order Filter Providing Notch,
Bandpass, Lowpass
Figure 5. Mode 1a: 2nd Order Filter Providing
Bandpass, Lowpass
1060fb
11
LTC1060
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ODES OF OPERATIO
R6
R5
R6
R5
R3
R2
R3
R2
N
S1A
(16)
BP
(19)
LP
(20)
N
(18)
S1A
(16)
BP
(19)
LP
(20)
2
1
5
2
1
3
5
3
R1
R1
V
IN
V
IN
4
4
–
+
–
+
–
–
+
+
(17)
(17)
∫
∫
Σ
Σ
∫
∫
–
–
S
S
A/B
A/B
TLC1060 • MOO04
TLC1060 • MOO03
1/2 LTC1060
R3
1/2 LTC1060
6
15
6
15
+
–
V
V
f
R6
R5 + R6
R6
R5 + R6
CLK
100(50)
f
R6
R5 + R6
R3
R2
R6
R5 + R6
CLK
100(50)
f
=
1 +
; f = f ; Q =
1 +
;
0
n
0
f
=
; f = f ; Q =
0
n
0
R2
f
R2
= – ; H
R3
R1
–R2/R1
1 + R6/(R5 + R6)
CLK
2
←
←
H
(f 0) = H
f
= –
; H =
0LP
; R5 < 5kΩ
f
0N1
0N2
0BP
(
)
R2
R1
–R2/R1
R6/(R5 + R6)
R3
R1
CLK
2
R1
←
←
H
0N1
(f 0) = H
f
= –
; H
0LP
=
; H
0BP
= –
; R5 < 5kΩ
0N2
(
)
Figure 6. Mode 1b: 2nd Order Filter Providing Notch,
Bandpass, Lowpass
Figure 7. Mode 1c: 2nd Order Filter Providing Notch,
Bandpass, Lowpass
R4
R4
R3
R2
R6
R5
2
R3
R2
N
(18)
S1A
(16)
BP
(19)
LP
(20)
N
(18)
S1A
(16)
BP
(19)
LP
(20)
2
1
1
3
5
3
5
R1
R1
V
V
IN
IN
4
4
–
+
–
+
–
–
+
+
(17)
(17)
∫
∫
Σ
Σ
∫
∫
–
–
S
A/B
S
A/B
TLC1060 • MOO05
TLC1060 • MOO06
1/2 LTC1060
1/2 LTC1060
6
15
6
15
+
+
V
V
f
f
CLK
100(50)
R2
R4
R3
R2
R2
R4
–R2/R1
1 + (R2 + R4)
CLK
f
f
R2
R6
R6
R5 + R6
R3
R2
R2
R6
CLK
CLK
1 +
f
=
1 +
; f
n
=
; Q =
1 +
; H
=
0
0LP
f
f
=
1 +
+
; f
=
n
; Q =
1 +
+
0
100(50)
R4 R5 + R6
R4 R5 + R6
100(50)
100(50)
–R2/R1
CLK
f
R2
R1
1 + R6/(R5 + R6)
1 + (R2/R4) + [R6/(R5 + R6)]
CLK
←
←
H
= – R3/R1 ; H (f 0) =
; H
=
0N2
f
= – R2/R1
0BP
0N1
←
←
H
H
(f 0) = –
; H
f
0N2
= – R2/R1
(
)
0N1
0BP
(
)
1 + (R2 + R4)
2
2
–R2/R1
1 + (R2/R4) + [R6/(R5 + R6)]
= – R3/R1 ; H
=
0LP
Figure 8. Mode 2: 2nd Order Filter Providing Notch,
Bandpass, Lowpass
Figure 9. Mode 2a: 2nd Order Filter Providing Notch,
Bandpass, Lowpass
1060fb
12
LTC1060
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ODES OF OPERATIO
R4
R6
R3
R4
R3
R2
R5
N
(18)
S1A
(16)
BP
(19)
LP
(20)
2
1
3
5
R2
N
(18)
S1A
(16)
BP
(19)
LP
(20)
2
1
3
5
R1
V
IN
4
–
+
–
R1
+
V
(17)
IN
4
–
+
Σ
∫
∫
–
+
(17)
–
∫
∫
Σ
–
S
A/B
TLC1060 • MOO08
1/2 LTC1060
S
6
15
A/B
TLC1060 • MOO07
1/2 LTC1060
6
15
–
V
–
V
f
R2
R4
R3
R2
R2
R4
CLK
f
=
; Q =
; H
= –R2/R1; H
= –R3/R1; H = –R4/R1
0LP
0
0HP
0BP
100(50)
f
f
CLK
100(50)
R2
R6
R4 R5 + R6
R6
R5 + R6
R3
R2
R2
R6
R4 R5 + R6
CLK
100(50)
f =
+
; f =
n
; Q =
f
+
0
Figure 11. Mode 3: 2nd Order Filter Providing Highpass,
Bandpass, Lowpass
R2
R1
R6/(R5 + R6)
(R2/R4) + [R6/(R5 + R6)]
CLK
2
←
←
H
H
(f 0) = –
; H
f
= – R2/R1
0N1
0BP
0N2
(
)
–R2/R1
(R2/R4) + [R6/(R5 + R6)]
= – R3/R1 ; H
=
0LP
Figure 10. Mode 2b: 2nd Order Filter Providing Notch,
Bandpass, Lowpass
R4
R3
R2
HP
S1A
(16)
BP
(19)
LP
(20)
2
1
3
5
(18)
R1
V
IN
4
–
+
–
+
(17)
Σ
∫
∫
R
g
–
R
I
–
S
A/B
6
1/2 LTC1060
EXTERNAL
OP AMP
15
NOTCH
R
h
+
–
V
f
f
CLK
100(50)
R2
R4
R
h
CLK
–
–
–
f
=
; f
•
=
; H
=
R2/R1; H
R2
=
R3/R1, H =
0LP
R4/R1
0
n
0HP
=
0BP
R
100(50)
I
R
f
R
R
R
g
R4
R1
g
h
g
g
h
R3
R2
R2
R4
CLK
←
←
H
(f 0) =
; H
f
•
; H (f = f ) = Q
H
–
H
; Q =
0N1
0N2
0N
0
0LP
0HP
(
)
(
)
R
R
R1
R
R
2
I
I
TLC1060 • MOO09
Figure 12. Mode 3a: 2nd Order Filter Providing Highpass,
Bandpass, Lowpass, Notch
1060fb
13
LTC1060
U
W
ODES OF OPERATIO
R4
R3
R2
HP
S1A
(16)
BP
LP
(20)
3
5
2
1
R3
R2
(18)
(19)
R1
V
IN
4
–
+
AP2
(18)
S1A
(16)
BP
LP
(20)
–
2
1
3
5
+
(19)
(17)
Σ
∫
∫
R1 = R2
–
V
IN
4
–
+
R5
–
+
(17)
Σ
∫
∫
–
S
A/B
R
1/2 LTC1060
6
15
–
EXTERNAL
OP AMP
+
S
A/B
TLC1060 • MOO10
–
2R
V
1/2 LTC1060
6
15
+
V
f
R2
R4
R3
R2
R2
R4
R5
2R
R2
R1
R3
R1
R4
R1
CLK
100(50)
f
R3
R2
R2
R1
R3
R2
f
0
=
; Q =
; H
0AP
=
; H
= –
;
H
= –
;
H
0LP
= –
CLK
0HP
0BP
f
0
=
; Q =
100(50)
; H
OAP
= –
; H
= –2 H
= – 2
OBP
OLP
(
)
TLC1060 • MOO11
Figure 13. Mode 4: 2nd Order Filter Providing Allpass,
Bandpass, Lowpass
Figure 14. Mode 4a: 2nd Order Filter Providing Highpass,
Bandpass, Lowpass, Allpass
R4
R3
R3
R2
R2
CZ
(18)
S1A
(16)
BP
(19)
LP
(20)
2
1
3
5
N
(18)
S1A
(16)
BP
(19)
LP
(20)
2
1
3
5
R1
V
4
IN
–
+
R1
–
+
V
(17)
IN
4
–
+
∫
∫
Σ
–
+
(17)
–
∫
∫
Σ
–
S
A/B
TLC1060 • MOO12
1/2 LTC1060
6
15
S
A/B
TLC1060 • MOO13
1/2 LTC1060
6
15
+
V
f
f
R2
R4
R1
R4
R3
R2
R2
R4
CLK
100(50)
CLK
100(50)
f
0
=
1 +
; f
=
1 –
; Q =
1 +
z
–
V
f
R2
CLK
100(50) R3
f
R3
R1
R1
R4
(R4/R1) –1
(R4/R2) + 1
R2
R1
CLK
2
f
=
; H
0LP
= –R3/R1 ; H
= –R2/R1
0HP
C
Q
=
1 –
; H = (f
OZ
←
0) =
; H
f
←
=
;
2
OZ
(
)
R3
R2
R2
R1
1 + (R2/R1)
=
H
=
1 +
; H
OBP
OLP
(
)
1 + (R2/R4)
Figure 15. Mode 5: 2nd Order Filter Providing Numerator
Complex Zeros, Bandpass, Lowpass
Figure 16. Mode 6a: 1st Order Filter Providing Highpass,
Lowpass
1060fb
14
LTC1060
U
W
ODES OF OPERATIO
R3
V
R2=R1
IN
R3
R2
AP
S1A
(16)
LP
2
(20)
1
3
5
(18)
(19)
R1=R2
LP1
(18)
S1A
(16)
LP2
(19)
(20)
1
2
V
3
5
4
IN
–
+
–
+
(17)
∫
∫
Σ
4
–
+
–
–
+
(17)
∫
∫
Σ
–
S
A/B
6
TLC1060 • MOO15
1/2 LTC1060
15
S
A/B
TLC1060 • MOO14
R3
= 2 x
H
1/2 LTC1060
OLP
–
6
15
R2
; GAIN AT AP OUTPUT = 1 FOR 0 ≤ f ≤
V
f
R2
f
R2
f
CLK
100(50) R3
CLK
100(50) R3
CLK
2
f
R2
R3
R2
CLK
100(50) R3
f
=
; f =
z
P
f
=
; H
OLP1
= 1 ; H
= –
C
OLP2
–
V
Figure 17. Mode 6b: 1st Order Filter Providing Lowpass
Figure 18. Mode 7: 1st Order Filter Providing Allpass, Lowpass
U
W W U
W
U
COMM E TS ON THE M ODES OF OPERATIO
There are basically three modes of operation: mode 1,
mode 2, mode 3. In the mode 1 (Figure 4), the input
amplifier is outside the resonant loop. Because of this,
mode 1 and its derivatives (mode 1a, 1b, 1c) are faster
than modes 2 and 3. In mode 1, for instance, the Q errors
are becoming noticeable above 1MHz clock frequency.
The practical clock-to-center frequency ratio range is:
500
1
f
100
1
50
1
CLK
≥
≥
≥
or
; mode 1b
f
0
f
100 50
or
100
√2
50
CLK
f
≥
or
; mode 1c
1
1
√2
o
Mode 1a (Figure 5), represents the most simple hook-up
oftheLTC1060.Mode1aisusefulwhenvoltagegainatthe
bandpass output is required. The bandpass voltage gain,
however, is equal to the value of Q; if this is acceptable,
asecondorder,clocktunable,BPresonatorcanbe achiev-
edwithonly2resistors.Thefiltercenterfrequencydirectly
depends on the external clock frequency. For high order
filters, mode1aisnotpracticalsinceitmayrequireseveral
clock frequencies to tune the overall filter response.
The input impedance of the S1 pin is clock dependent,
and in general R5 should not be larger than 5k. Mode 1b
can be used to increase the clock-to-center frequency
ratio beyond 100:1. For this mode, a practical limit for the
(f /f ) ratio is 500:1. Beyond this, the filter will exhibit
laCrgLKe 0output offsets. Mode 1c is the fastest mode of
operation: In the 50:1 mode and with (R5 = 0, R6 = ∞) the
clock-to-centerfrequencyratiobecomes(50/√2)andcen-
ter frequencies beyond 20kHz can easily be achieved as
shown in Graph 25. Figure 19 illustrates how to cascade
the two sections of the LTC1060 connected in mode 1c to
obtain a sharp fourth order, 1dB ripple, BP Chebyshev
filter.NotethatthecenterfrequencytotheBWratioforthis
fourth order bandpass filter is 20/1. By varying the clock
frequency to sweep the filter, the center frequency of the
overallfilterwillincreaseproportionallyandsowilltheBW
to maintain the 20:1 ratio constant. All the modes of
operation yield constant Q’s; with any filter realization the
BW’s will vary when the filter is swept. This is shown in
Figure 19, where the BP filter is swept from 1kHz to 20kHz
center frequency.
Mode 1 (Figure 4), provides a clock tunable notch; the
depth is shown in Graph 14. Mode 1 is a practical
configuration for second order clock tunable bandpass/
notch filters. In mode 1, a bandpass output with a very
high Q, together with unity gain, can be obtained without
creating problems with the dynamics of the
remaining notch and lowpass outputs.
Modes 1b and 1c (Figures 6 and 7), are similar. They both
produce a notch with a frequency which is always equal to
the filter building block center frequency. The notch and
the center frequency, however, can be adjusted with an
external resistor ratio.
1060fb
15
LTC1060
U
W W U
W
U
COMM E TS ON THE M ODES OF OPERATIO
Modes2, 2a, and2bhaveanotchoutputwhichfrequency,
fn, can be tuned independently from the center frequency,
f0. For all cases, however, fn<f0. These modes are useful
when cascading second order functions to create an
overallelliptichighpass, bandpassornotchresponse. The
input amplifier and its feedback resistors (R2/R4) are now
part of the resonant loop. Because of this, mode 2 and its
derivatives are slower than mode 1’s.
f
= 40kHz
CLK
0dB
LTC1060
V
–5dB
OUT
R61
R51
R31
R21
R52
R32
R22
1
2
20
19
18
17
16
15
14
13
12
11
50Hz
LP
BP
N
LP
B
B
B
B
A
–10dB
BP
A
R62
R12
3
–15dB
–20dB
–25dB
N
A
R11
4
V
IN
INV
INV
A
5
S1B
S1A
6
+
AGND
–
S
V
= 5V
A/B
7
+
0.9kHz
1kHz
1kHz
1.1kHz
–
V
A
V
A
V
= –5V
8
–
+
V
D
V
D
f
= 800kHz
CLK
0dB
9
5V
50/100
LSh
CLK
–5dB
10
CLK
B
A
–10dB
2
T L OR CMOS CLK IN
–15dB
–20dB
–25dB
PRECISE RESISTOR VALUES
R11 = 149.21k
R21 = 4.99k
R31 = 149.12k
R51 = 2.55k
R61 = 2.49k
R12 = 45.14k
R22 = 5.00k
R32 = 142.64k
R5 = 2.49k
R62 = 4.29k
LTC1060 • CM01
18kHz
19kHz
20kHz
21kHz
22kHz
TLC1060 • CMO01b
Figure 19. Cascading the Two Sections of the LTC1060 Connected in Mode 1c to Obtain a Clock Tunable 4th Order
1dB Ripple Bandpass Chebyshev Filter with (Center Frequency)/(Ripple Bw) = 20/1.
In mode 3 (Figure 11), a single resistor ratio (R2/R4) can
tune the center frequency below or above the fCLK/100
(or fCLK/50) ratio. Mode 3 is a state variable configuration
since it provides a highpass, bandpass, lowpass output
through progressive integration; notches are obtained by
summing the highpass and lowpass outputs (mode 3a,
Figure 12). The notch frequency can be tuned below or
above the center frequency through the resistor ratio
(Rh/Ri). Because of this, modes 3 and 3a are the most
versatile and useful modes for cascading second order
sections to obtain high order elliptic filters. Figure 20
showsthetwosectionsofanLTC1060connectedinmode
3a to obtain a clock tunable 4th order sharp elliptic
bandpass filter. The first notch is created by summing
directly the HP and LP outputs of the first section into the
inverting input of the second section op amp. The indi-
vidual Q’s are 29.6 and the filter maintains its shape and
performance up to 20kHz center frequency (Figure 21).
For this circuit an external op amp is required to obtain the
2nd notch. The dynamics of Figure 20 are excellent be-
cause the amplitude response at each output pin does not
exceed0dB. Thegaininthepassbanddependsontheratio
of (Rg/Rh2) • (R22/Rh1)• (R21/R11). Any gain value can be
obtained by acting on the (Rg/Rh2) ratio of the external op
amp, meanwhile the remaining ratios are adjusted for
optimum dynamics of the LTC1060 output nodes. The
external op amp of Figure 20 is not always required. In
Figure 22, one section of the LTC1060 in mode 3a is
cascaded with the other section in mode 2b to obtain a 4th
order, 1dB ripple, elliptic bandreject filter. This configura-
tion is interesting because a 4th order function with two
different notches is realized without requiring an external
op amp. The clock-to-center frequency ratio is adjusted to
200:1; this is done in order to better approximate a linear
R,C notch filter. The amplitude response of the filter is
shown in Figure 23 with up to 1MHz clock frequency. The
0dB bandwidth to the stop bandwidth ratio is 9/1. When
the filter is centered at 1kHz, it should theoretically have a
44dB rejection with a 50Hz stop bandwidth. For a more
narrow filter than the above, the unused BP output of the
1060fb
16
LTC1060
U
W W U
W
U
COMM E TS ON THE M ODES OF OPERATIO
mode 2b section (Figure 22), has a gain exceeding unity
which limits the dynamic range of the overall filter. For
very selective bandpass/bandreject filters, the mode 3a
approach, as in Figure 20, yields better dynamic range
since the external op amp helps to optimize the dynamics
of the output nodes of the LTC1060.
R
H1
L1
R
G
R
R
L2
LTC1060
–
R42
R32
R22
R41
R31
R21
1
2
20
19
18
17
16
15
14
13
12
11
EXTERNAL
OP AMP
+
V
OUT
LP
BP
HP
LP
B
B
B
B
A
BP
A
3
R
H2
HP
A
R11
4
V
IN
INV
INV
A
5
S1B
S1A
6
AGND
–
S
–7.5V
A/B
7
+
+
V
V
A
= 7.5V
V
A
–7.5V
8
–
+
V
D
V
D
9
7.5V
50/100
LSh
CLK
10
CLK
B
A
2
T L OR CMOS
CLOCK IN
PRECISE RESISTOR VALUES
R11 = 155.93k
R21 = 5k
R31 = 152k
R22 = 5.26k
R41 = 5.27k
R32 = 151.8k
R = 37.3k
G
R
= 13.2k
R
L1
R
L2
= 10.74k
= 6.11k
H1
R42 = 5k
R
H2
= 5k
NOTE: FOR CLOCK FREQUENCIES ABOVE 700kHz, A 12pF CAPACITOR ACROSS R41 AND A 20pF
CAPACITOR ACROSS R42 WERE USED TO PREVENT THE PASSBAND RIPPLE FROM ANY
ADDITIONAL PEAKING
LTC1060 • CM02
Figure 20. Combining Mode 3 with Mode 3a to Make The 4th Order BP Filter of Figure 21 with Improved
Dynamics. The Gain at Each Output Node is ≤ 0dB for all Input Frequencies.
f
= 100kHz
f
= 1MHz
CLK
CLK
0dB
0dB
–10dB
–10dB
–20dB
–30dB
–20dB
–30dB
–40dB
–40dB
–50dB
–50dB
1.5kHz
1.75kHz
2kHz
2.25kHz
2.5kHz
15kHz
17.5kHz
20kHz
22.5kHz
25kHz
TLC1060 • CMO03
Figure 21. The BP Filter of Figure 20, When Swept From a 2kHz to 20kHz Center Frequency.
1060fb
17
LTC1060
U
W W U
W
U
COMM E TS ON THE M ODES OF OPERATIO
f
R
200
1
CLK
H1
=
; f
CLK
≤ 1MHz
f
0
R
L1
LTC1060
0
–10
–20
–30
–40
–50
–60
R42
R52
R32
R22
R41
R31
R21
1
2
20
19
18
17
16
15
14
13
12
11
LP
BP
N
LP
B
B
B
B
A
BP
A
R62
3
HP
A
R11
4
V
IN
INV
INV
A
V
OUT
5
S1B
S1A
6
AGND
–
–5V
= –5V
S
V
V
A/B
7
+
+
–
V
A
V
V
= –5V
A
8
–
+
V
D
D
9
50/100
LSh
CLK
10
CLK
B
A
2
T L OR CMOS
CLOCK IN
RESISTOR VALUES
R21 = 5k
= 5k
R62 = 1.59k
R11 = 60k
R31 = 54.75k
R = 19.3k
R41 = 28.84k
R52 = 5k
R32 = 455.75k
R
H1
L1
R22 = 60k
0.7
0.9
f
= 1.0
1.1
1.2
1.3
0.8
0
R42 = 503.85k
LTC1060 • CM04
INPUT FREQUENCY NORMALIZED TO FILTER CENTER FREQUENCY
TLC1060 • CMO05
Figure 22. Combining Mode 3 with Mode 2b to Create a 4th
Order BR Elliptic Filter with 1dB Ripple and a Ratio of 0dB to
Stop Bandwidth Equal to 9/1.
Figure 23. Amplitude Response of the Notch Filter of Figure 22
LTC1060 OFFSETS
Switched capacitor integrators generally exhibit higher
input offsets than discrete R, C integrators. These offsets
are mainly due to the charge injection of the CMOS
switches into the integrating capacitors and they are
temperature independent.
Figure 24 shows half of an LTC1060 filter building block
with its equivalent input offsets VOS1, VOS2, VOS3. All three
are 100% tested for both sides of the LTC1060. VOS2 is
generally the larger offset. When the SA/B, Pin 6, of the
LTC1060 is shorted to the negative supply (i.e., mode 3),
the value of the VOS2 decreases. Additionally, with SA/B
low, a 20% to 30% noise reduction is observed. Mode 1
can still be achieved, if desired, by shorting the S1 pin to
the lowpass output (Figure 25).
The internal op amp offsets also add to the overall offset
budget and they are typically a couple of millivolts. Be-
cause of this, the DC output offsets of switched capacitor
filters are usually higher than the offsets of discrete active
filters.
R3
R2
(18) (16)
(19)
2
(20)
1
3
5
V
OS1
N
(18)
S1A
(16)
BP
(19)
LP
(20)
(17)
4
2
1
3
5
+
–
V
–
+
OS2
–
–
R1
+
+
–
V
V
IN
OS3
–
+
4
Σ
–
+
–
+
–
+
(17)
–
+
∫
∫
Σ
–
S
A/B
TLC1060 • LO02
TLC1060 • LO01
1/2 LTC1060
6
15
15
–
V
Figure 24. Equivalent Input Offsets of 1/2 LTC1060 Filter
Building Block
Figure 25. Mode 1(LN): Same Operation as Mode 1 but Lower
VOS2 Offset and Lower Noise
1060fb
18
LTC1060
LTC1060 OFFSETS
Output Offsets
dynamic range. As a rule of thumb, the output DC offsets
increase when:
The DC offset at the filter bandpass output is always equal
to VOS3. The DC offsets at the remaining two outputs
(Notch and LP) depend on the mode of operation and
external resistor ratios. Table 5 illustrates this.
1. The Q’s decrease.
2. The ratio (fCLK/f0) increases beyond 100:1. This is
done by decreasing either the (R2/R4) or the
R6/(R5 + R6) resistor ratios.
It is important to know the value of the DC output offsets,
especially when the filter handles input signals with large
Table 5
V
V
V
OSLP
PIN 1 (20)
OSN
OSBP
MODE
1,4
1a
PIN 3 (18)
PIN 2 (19)
V
V
V
V
[(1/Q) + 1 + ||H ||] – V /Q
V
V
V
V
V
V
– V
– V
OS1
OS1
OS1
OS1
OLP
OS3
OS3
OS3
OS3
OS3
OSN
OSN
OS2
OS2
[1 + (1/Q)] – V /Q
OS3
1b
[(1/Q) + 1 + R2/R1] – V /Q
~ (V
– V ) (1 + R5/R6)
OS3
OSN
OS2
1c
[(1/Q) + 1 + R2/R1] – V /Q
(R5 + R6)
(R5 + 2R6)
OS3
~(VOSN – VOS2
)
)
2, 5
2a
[V (1 + R2/R1 + R2/R3 + R2/R4) – V (R2/R3)]
V
V
– V
OSN OS2
OS1
OS3
OS3
• [R4/(R2 + R4)] + V [R2/(R2 + R4)]
OS2
[VOS1(1 + R2/R1 + R2/R3 + R2/R4) – VOS3(R2/R3)]
R4(1 + k)
R2
R6
R5 + R6
(R5 + R6)
(R5 + 2R6)
•
+ VOS2
;k =
~(VOSN – VOS2
R2 + R4(1 + k)
R2 + R4(1 + k)
V
OS3
[VOS1(1 + R2/R1 + R2/R3 + R2/R4) – VOS3(R2/R3)]
2b
R4k
R2 + R4k
R2
R2 + R4k
R6
R5 + R6
•
+ VOS2
;k =
V
V
~ (V
– V ) (1 + R5/R6)
OS3
OS3
OSN
OS2
3, 4a
V
R4 R4 R4
R4
R2
OS2
VOS1 1 +
+
+
– VOS2
R1 R2 R3
R4
R3
– VOS3
U
PACKAGE DESCRIPTIO
N Package
20-Lead PDIP (Narrow .300 Inch)
(Reference LTC DWG # 05-08-1510)
.300 – .325
(7.620 – 8.255)
1.040*
(26.416)
MAX
.045 – .065
(1.143 – 1.651)
.125 – .145
(3.175 – 3.683)
20
19
18
17
16
15
14
13
12
11
10
.020
(0.508)
MIN
.065
(1.651)
TYP
.255 ± .015*
(6.477 ± 0.381)
.008 – .015
(0.203 – 0.381)
+.035
.005
(0.127)
MIN
.120
(3.048)
MIN
.018 ± .003
(0.457 ± 0.076)
.325
.100
(2.54)
BSC
–.015
3
4
5
6
7
8
9
1
2
+0.889
8.255
NOTE:
1. DIMENSIONS ARE
(
)
–0.381
INCHES
MILLIMETERS
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .010 INCH (0.254mm)
N20 1002
1060fb
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 represen-
tationthattheinterconnectionofitscircuitsasdescribedhereinwillnotinfringeonexistingpatentrights.
19
LTC1060
U
PACKAGE DESCRIPTIO
J Package
20-Lead CERDIP (Narrow .300 Inch, Hermetic)
(Reference LTC DWG # 05-08-1110)
1.060
(26.924)
MAX
CORNER LEADS OPTION
(4 PLCS)
20
19
18
17
16
15
14
13
12
11
10
.023 – .045
.025
(0.635)
RAD TYP
(0.584 – 1.143)
HALF LEAD
OPTION
.220 – .310
(5.588 – 7.874)
.045 – .065
(1.143 – 1.650)
FULL LEAD
OPTION
1
2
.005
3
4
5
6
7
8
9
.200
(5.080)
MAX
.300 BSC
(7.62 BSC)
(0.127)
MIN
.015 – .060
(0.381 – 1.524)
.008 – .018
(0.203 – 0.457)
0° – 15°
.125
(3.175)
MIN
.045 – .065
(1.143 – 1.651)
.100
(2.54)
BSC
NOTE: LEAD DIMENSIONS APPLY TO SOLDER DIP/PLATE
OR TIN PLATE LEADS
.014 – .026
(0.356 – 0.660)
J20 0801
OBSOLETE PACKAGE
SW Package
20-Lead Plastic Small Outline (Wide .300 Inch)
(Reference LTC DWG # 05-08-1620)
.050 BSC .045 ±.005
.030 ±.005
TYP
.496 – .512
(12.598 – 13.005)
NOTE 4
N
19 18
16
14 13 12 11
20
N
17
15
.325 ±.005
.420
MIN
.394 – .419
(10.007 – 10.643)
NOTE 3
1
2
3
N/2
N/2
10
RECOMMENDED SOLDER PAD LAYOUT
.291 – .299
(7.391 – 7.595)
NOTE 4
2
3
5
7
8
9
1
4
6
.037 – .045
.093 – .104
(2.362 – 2.642)
.010 – .029
(0.254 – 0.737)
(0.940 – 1.143)
× 45°
.005
(0.127)
RAD MIN
0° – 8° TYP
.050
(1.270)
BSC
.004 – .012
.009 – .013
(0.102 – 0.305)
NOTE 3
(0.229 – 0.330)
.014 – .019
.016 – .050
(0.406 – 1.270)
INCHES
(MILLIMETERS)
S20 (WIDE) 0502
(0.356 – 0.482)
TYP
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)
1060fb
LW/TP 1202 1K REV B • PRINTED IN USA
20 LinearTechnology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
■
■
(408) 432-1900 FAX: (408) 434-0507 www.linear.com
LINEAR TECHNOLOGY CORPORATION 1988
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