LTC1065 Datasheet, PDF (1/12 Pages) Linear Technology – DC Accurate, Clock-Tunable Linear Phase 5th Order Bessel Lowpass Filter

FEATURES
s _{Clock-Tunable Cutoff Frequency}
s _{1mV DC Offset (Typical)}
s _{80dB CMR (Typical)}
s _{Internal or External Clock}
s _{50µVRMS Clock Feedthrough}
s _{100:1 Clock-to-Cutoff Frequency Ratio}
s _{80µVRMS Total Wideband Noise}
s _{0.004% Noise + THD at 2VRMS Output Level}
s _{50kHz Maximum Cutoff Frequency}
s _{Cascadable for Faster Roll-Off}
s _{Operates from ±2.375 to ±8V Power Supplies}
s _{Self-Clocking with 1 RC}
APPLICATI S
s _Audio
s _{Strain Gauge Amplifiers}
s _{Anti-Aliasing Filters}
s _{Low Level Filtering}
s _{Digital Voltmeters}
s _{Smoothing Filters}
s _{Reconstruction Filters}
TYPICAL APPLICATI
3.4kHz Single 5V Supply Bessel Lowpass Filter
5V
4.99k
+ _{1µF 4.53k}
TANT
V_IN ¹
2
0.1µF 3
4
LTC1065
8
7
V_OUT
6
5V
5
0.1µF
13k*
* SELF-CLOCKING SCHEME
200pF*
1065 TA01
LTC1065
DC Accurate, Clock-Tunable
Linear Phase 5th Order Bessel
Lowpass Filter
DESCRIPTIO
The LTC1065 is the first monolithic filter providing both
clock-tunability with low DC output offset and over 12-bit
DC accuracy. The frequency response of the LTC1065
closely approximates a 5th order Bessel polynomial. With
appropriate PCB layout techniques the output DC offset is
typically 1mV and is constant over a wide range of clock
frequencies. With ±5V supplies and ±4V input voltage
range, the CMR of the device is typically 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 nearly power supply inde-
pendent and it is programmed via an external RC. The
50µV_RMS clock feedthrough of the device is considerably
lower than other existing monolithic filters.
The LTC1065 wideband noise is 80µV_RMS and it can
process large AC input signals with low distortion. With
± 7.5V supplies, for instance, the filter handles up to
4V_RMS (94dB S/N ratio) while the standard 1kHz THD is
below 0.005%; 87dB dynamic range (S/N + THD) is ob-
tained with input levels between 2V_RMS and 2.5V_RMS.
The LTC1065 is available in 8-pin miniDIP and 16-pin SOL.
For a Butterworth response, see LTC1063 data sheet. The
LTC1065 is pin compatible with the LTC1063.
10
0
–10
– 20
– 30
– 40
– 50
– 60
– 70
– 80
– 90
1
Frequency Response
10
FREQUENCY (kHz)
100
1065 TA02
1