Features

• 5th Order, 1MHz Elliptic Filter in SO-8 Package
• Pin Selectable 1MHz/500kHz Cutoff Frequency
• Signal-to-Noise Ratio (SNR): 75dB
• Signal-to-Noise Ratio with –63dB THD: 69dB
• Passband Ripple (f_CUTOFF = 1MHz): ±0.3dB
• Stopband Attenuation Better Than 60dB
• No External Components Required

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 selectivity, for antialiasing applications, and transient response. The filter cutoff frequency, f_CUTOFF, is pin selectable to 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 0.55f_CUTOFF and ±0.3dB to 0.9f_CUTOFF. The transition band gain is –24dB at 1.4f_CUTOFF and –51dB at 2f_CUTOFF. Stopband attenuation is 63dB at 2.43f_CUTOFF and above, remaining at least 60dB to 10MHz with proper board layout. When the LTC1560-1 is programmed for f_CUTOFF = 500kHz, the filter response closely follows the 1MHz case with the exception of passband flatness near the cutoff frequency; the gain at f_CUTOFF is –1.3dB.

The LTC1560-1, unlike other high frequency filters, is designed for low noise and low distortion. With a 1V_RMS input signal, the signal-to-noise ratio is 69dB and the THD is –63dB. The maximum SNR of 75dB is obtained with a 2.1V_RMS 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.