LTC1063
DC Accurate, Clock-Tunable
5th Order Butterworth
Lowpass Filter
FEATURES
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DESCRIPTIO
Clock-Tunable Cutoff Frequency
1mV DC Offset (Typical)
80dB CMRR (Typical)
Internal or External Clock
50碌V
RMS
Clock Feedthrough
100:1 Clock-to-Cutoff Frequency Ratio
95碌V
RMS
Total Wideband Noise
0.01% THD at 2V
RMS
Output Level
50kHz Maximum Cutoff Frequency
Cascadable for Faster Roll-Off
Operates from
鹵2.375
to
鹵8V
Power Supplies
Self-Clocking with 1 RC
The LTC1063 is the first monolithic filter providing both
clock-tunability, low DC output offset and over 12-bit DC
accuracy. The frequency response of the LTC1063 closely
approximates a 5th order Butterworth polynomial. With
appropriate PCB layout techniques the output DC offset is
typically 1mV and is constant over a wide range of clock
frequencies. With
鹵5V
supplies and
鹵4V
input voltage
range, the CMR of the device is 80dB.
The filter cutoff frequency is controlled either by an inter-
nal or external clock. The clock-to-cutoff frequency ratio is
100:1. The on-board clock is power supply independent,
and it is programmed via an external RC. The 50碌V
RMS
clock feedthrough is considerably reduced over existing
monolithic filters.
The LTC1063 wideband noise is 95碌V
RMS
, and it can
process large AC input signals with low distortion. With
鹵7.5V
supplies, for instance, the filter handles up to
4V
RMS
(92dB S/N ratio) while the standard 1kHz THD is
below 0.02%; 80dB dynamic ranges (S/N +THD) is ob-
tained with input levels between 1V
RMS
and 2.3V
RMS
.
The LTC1063 is available in 8-pin miniDIP and 16-pin SOL.
For a linear phase response, see LTC1065 data sheet.
APPLICATI
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Audio
Strain Gauge Amplifiers
Anti-Aliasing Filters
Low Level Filtering
Digital Voltmeters
60Hz Lowpass Filters
Smoothing Filters
Reconstruction Filters
TYPICAL APPLICATI
V
IN
** 1
2
3
鈥?V
4
LTC1063
2.5kHz 5th Order Lowpass Filter
8
7
6
5
V
OUT
5V
0.1碌F
10
0
鈥?0
鈥?0
GAIN (dB)
鈥?0
鈥?0
鈥?0
鈥?0
0.1碌F
*19.1k
200pF*
*
SELF-CLOCKING SCHEME
+
**
IF THE INPUT VOLTAGE CAN EXCEED V ,
鈥?0
鈥?0
鈥?0
1
10
FREQUENCY (kHz)
100
1063 TA02
CONNECT A SIGNAL DIODE BETWEEN PIN 1 AND V
+
.
1063 TA01
U
Frequency Response
UO
UO
1