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LTC1264

High Speed, Quad Universal

Filter Building Block

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FEATURE

DESCRIPTIO

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High Speed, Up to 250kHz Center Frequency

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Four Identical Filters in a 0.3" Wide Package

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Clock-to-Center Frequency Ratio of 20:1

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Double-Sampling, Improved Aliasing

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Operates from

±2.37V to ±8V Power Supplies

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Customized Version with Internal Resistors Available

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Low Noise

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Low Harmonic Distortion

The LTC

order switched-capacitor filter building blocks designed

for center frequencies up to 250kHz. Each building block,

together with three to five resistors, can provide 2nd order

functions like lowpass, highpass, bandpass and notch.

The center frequency of each 2nd order section is tuned via

an external clock. The clock-to-center frequency ratio is

internally set to 20:1, but it can be modified via external

resistors.

The aliasing performance of the LTC1264 is improved by

double-sampling each 2nd order section. Input signal

frequencies can reach up to twice the clock frequency

before any alias products will be detectable.

For Q

frequency is 160kHz. For Q

≤ 2, the maximum center

frequency is 250kHz. Up to 8th order filters can be realized

by cascading all four 2nd order sections.

A customized monolithic version of the LTC1264 includ-

ing internal thin film resistors can be obtained.

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Digital Communications

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Spread Spectrum Communications

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Spectral Analysis

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Loran Receivers

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Instrumentation

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APPLICATI

APPLICATI

TYPICAL

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

50k

10k

50k

10k

IN

1264 TA01

OUT

INV B

HPB/NB

BPB

LPB

SB

AGND

SA

LPA

BPA

HPA/NA

INV A

INV C

HPC/NC

BPC

LPC

SC

CLK

SD

LPD

BPD

HPD/ND

INV D

50k

50k

50k

10k

50k

10k

50k

50k

LTC1264

MAXIMUM

160kHz

120kHz

60kHz

POWER

SUPPLY

±7.5V

±5V

Single 5V

0.1

µF

0.1

µF

FREQUENCY (Hz)

10k

10

0

–10

–20

–30

–40

–50

–60

–70

–80

100k

1M

1264 TA02

Gain vs Frequency