1

LTC1062

1062fd

10Hz 5th Order Butterworth Lowpass Filter

Filter Amplitude Response and Noise

■

Lowpass Filter with No DC Error

■

Low Passband Noise

■

Operates DC to 20kHz

■

Operates On a Single 5V Supply or Up to ±8V

■

5th Order Filter

■

Maximally Flat Response

■

Internal or External Clock

■

Cascadable for Faster Rolloff

■

Buffer Available

The LTC

lowpass filter with no DC error. Its unusual architecture

puts the filter outside the DC path so DC offset and low

frequency noise problems are eliminated. This makes the

LTC1062 very useful for lowpass filters where DC accuracy

is important.

The filter input and output are simultaneously taken across

an external resistor. The LTC1062 is coupled to the signal

through an external capacitor. This RC reacts with the

internal switched capacitor network to form a 5th order

rolloff at the output.

The filter cutoff frequency is set by an internal clock that

can be externally driven. The clock-to-cutoff frequency

ratio is typically 100:1, allowing the clock ripple to be

easily removed.

Two LTC1062s can be cascaded to form a 10th order quasi

max flat lowpass filter. The device can be operated with

single or dual supplies ranging from ±2.5V to ±9V.

The LTC1062 is manufactured using Linear Technology’s

enhanced LTCMOS

■

60Hz Lowpass Filters

■

Antialiasing Filter

■

Low Level Filtering

■

Rolling Off AC Signals from High DC Voltages

■

Digital Voltmeters

■

Scales

■

Strain Gauges

LTCMOS is a trademark of Linear Technology Corporation.

FB

AGND

DIVIDER

RATIO

OUT

1

2

3

4

8

7

6

5

LTC1062

3900pF

1062 TA01

1µF

25.8k

DC ACCURATE

OUTPUT

BUFFERED

OUTPUT

NOTE: TO ADJUST OSCILLATOR FREQUENCY,

USE A 6800pF CAPACITOR IN SERIES

WITH A 50k POT FROM PIN 5 TO GROUND

INPUT FREQUENCY (Hz)

1

–100

–80

–60

–40

–20

10

100

1062 TA02

0

–90

–70

–50

0

20

40

10

30

50

–30

–10

FEATURES

DESCRIPTIO

APPLICATIO S

TYPICAL APPLICATIO

, LTC and LT are registered trademarks of Linear Technology Corporation.

5th Order Lowpass Filter