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LTC1560-1

sn15601 15601fs

1MHz/500kHz

Continuous Time,

Low Noise, Lowpass Elliptic Filter

FEATURES

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5th Order, 1MHz Elliptic Filter in SO-8 Package

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Pin Selectable 1MHz/500kHz Cutoff Frequency

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Signal-to-Noise Ratio (SNR): 75dB

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Signal-to-Noise Ratio with – 63dB THD: 69dB

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Passband Ripple (fCUTOFF = 1MHz): ±0.3dB

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Stopband Attenuation Better Than 60dB

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No External Components Required

either 500kHz (Pin 5 to V +) or 1MHz (Pin 5 to V –). When

programmed for 1MHz, the passband ripple is typically

±0.2dB up to 0.55fCUTOFF and ±0.3dB to 0.9fCUTOFF. The

transition band gain is – 24dB at 1.4fCUTOFF and – 51dB at

2fCUTOFF. Stopband attenuation is 63dB at 2.43fCUTOFF and

above, remaining at least 60dB to 10MHz with proper

board layout. When the LTC1560-1 is programmed for

fCUTOFF = 500kHz, the filter response closely follows the

1MHz case with the exception of passband flatness near

the cutoff frequency; the gain at fCUTOFF is – 1.3dB.

The LTC1560-1, unlike other high frequency filters, is

designed for low noise and low distortion. With a 1VRMS

input signal, the signal-to-noise ratio is 69dB and the THD

is – 63dB. The maximum SNR of 75dB is obtained with a

2.1VRMS input signal. This results in – 46dB THD.

The LTC1560-1 operates with

±5V supplies, has a power

saving mode and is available in an SO-8 surface mount

package.

Other cutoff frequencies from 450kHz to 1.5MHz can be

obtained. Demo board DC135A is available for the

LTC1560-1. For more information please contact LTC

Marketing.

FREQUENCY (MHz)

0.1

–90

–70

–50

–30

–10

110

1560-1 TA02

10

–80

–60

–40

–20

0

fCUTOFF = 1MHz/500kHz

Frequency Response

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

TYPICAL APPLICATION

DESCRIPTION

The LTC

®1560-1 is a 5th order, continuous-time, lowpass

filter.

The elliptic transfer function of the LTC1560-1 was

carefully chosen to reach a compromise between selectiv-

ity, for antialiasing applications, and transient response.

The filter cutoff frequency, fCUTOFF, is pin selectable to

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Antialiasing Filters

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Smoothing or Reconstruction Filters

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Communication Filters

APPLICATIONS

VIN

VOUT

5V

(OR – 5V)

0.01

µF

0.1

µF

0.1

µF

–5V

1560-1 TA01

0.01

µF

–5V

1MHz

5V

500kHz

GND

V –

V +

GND

VIN

1

4

3

2

8

5

6

7

VOUT

SHDN

0.5fC/fC

LTC1560-1

1MHz/500kHz Elliptic Lowpass Filter