1

LTC1065

DC Accurate, Clock-Tunable

Linear Phase 5th Order Bessel

Lowpass Filter

3.4kHz Single 5V Supply Bessel Lowpass Filter

APPLICATI

TYPICAL

DESCRIPTIO

S

FEATURE

s

Clock-Tunable Cutoff Frequency

s

1mV DC Offset (Typical)

s

80dB CMR (Typical)

s

Internal or External Clock

s

50

s

100:1 Clock-to-Cutoff Frequency Ratio

s

80

s

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

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

50

lower than other existing monolithic filters.

The LTC1065 wideband noise is 80

process large AC input signals with low distortion. With

±7.5V supplies, for instance, the filter handles up to

below 0.005%; 87dB dynamic range (S/N + THD) is ob-

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.

S

APPLICATI

s

Audio

s

Strain Gauge Amplifiers

s

Anti-Aliasing Filters

s

Low Level Filtering

s

Digital Voltmeters

s

Smoothing Filters

s

Reconstruction Filters

4.53k

13k*

5V

0.1

µF

1065 TA01

SELF-CLOCKING SCHEME

*

200pF*

1

2

3

4

8

7

6

5

LTC1065

0.1

µF

5V

4.99k

+

1

µF

TANT

Frequency Response

FREQUENCY (kHz)

1

10

0

–10

–20

–30

–40

–50

–60

–70

–80

–90

10

100

1065 TA02