LTC1059
High Performance
Switched Capacitor Universal Filter
U
FEATURES
DESCRIPTIO
The LTC®1059 consists of a general purpose, high perfor-
mance, active filter building block and an uncommitted op
amp. The filter building block together with an external
clock and 2 to 5 resistors can produce various 2nd order
functions which are available at its three output pins. Two
out of three always provide lowpass and bandpass func-
tions while the third output pin can produce notch or
highpass or allpass. The center frequency of these func-
tions can be tuned from 0.1Hz to 40kHz and is dependent
on an external clock or an external clock and a resistor
ratio. Thefiltercanhandleinputfrequenciesupto100kHz.
The uncommitted op amp can be used to obtain additional
allpass and notch functions, for gain adjustment or for
cascading techniques.
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All Filter Parameters Guaranteed Over Temperature
Wide Center Frequency Range (0.1Hz to 40kHz)
Low Noise, Wide Dynamic Range
Guaranteed Operation for ±2.37V and ±5V Supply
Low Power Consumption
Guaranteed Clock-to-Center Frequency Accuracy of
0.8%
Guaranteed Low Offset Voltages Over Temperature
Very Low Center Frequency and Q Tempco
Clock Input T2L or CMOS Compatible
Separate Highpass (or Notch or Allpass), Bandpass,
Lowpass Outputs
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APPLICATIO S
Higher than 2nd order filter functions can be obtained by
cascading the LTC1059 with the LTC1060 dual universal
filter or the LTC1061 triple universal filter. Any classical
filter realization (such as Butterworth, Cauer, Bessel and
Chebyshev) can be formed.
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Sinewave Oscillators
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Sweepable Bandpass/Notch Filters
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Full Audio Frequency Filters
Tracking Filters
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, LTC and LT are registered trademarks of Linear Technology Corporation.
LTCMOS trademark of Linear Technology Corporation.
The LTC1059 can be operated with single or dual supplies
ranging from ±2.37V to ±8V (or 4.74V to 16V single
supply).
TheLTC1059ismanufacturedbyusingLinearTechnology’s
enhanced LTCMOSTM silicon gate process.
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TYPICAL APPLICATIO
Wide Range 2nd Order Bandpass/Notch Filter with Q = 10
Center Frequency and Q Error
30
25
20
15
10
5
1.2
1.0
0.8
0.6
0.4
0.2
0
T
= 25°C
A
NOTCH OUT
BP OUT
50k
CLOCK
CENTER FREQUENCY
35.35
1
=
1
2
3
4
5
6
7
14
13
12
11
10
9
BP
LP
LTC1059
7.15k
N/AP/HP
V
02
50k
V
IN
DC-200kHz
INV1
S1
INV2
CENTER
FREQUENCY
ERROR
AGND
–
–8V
S
V
V
A
+
Q ERROR
8V
50/100/HOLD
CLK
0
8
0
5
10 15 20 25 30 35 40 45
LSh
IDEAL CENTER FREQUENCY (kHz)
1058 TA01b
2
1059 TA01a
T L CLOCK IN ≤ 2MHz
1059fd
1