14-Bit DC Accurate Clock-Tunable, 8th Order Elliptic or Linear Phase Lowpass Filter

The LTC1066-1 is an 8th order elliptic lowpass filter which simultaneously provides clock-tunability and DC accuracy. The unique and proprietary architecture of the filter allows 14 bits of DC gain linearity and a maximum of 1.5mV DC offset. An external RC is required for DC accurate operation. With ±7.5V supplies, a 20k resistor and a 1µF capacitor, the cutoff frequency can be tuned from 800Hz to 100kHz. A clock-tunable 10Hz to 100kHz operation can also be achieved (see Typical Application section).

The filter does not require any external active components such as input/output buffers. The input/output impedance is 500MΩ/0.1Ω and the output of the filter can source or sink 40mA. When pin 8 is connected to V+ , the clock-to-cutoff frequency ratio is 50:1 and the input signal is sampled twice per clock cycle to lower the risk of aliasing. For frequencies up to 0.75fCUTOFF , the passband ripple is ±0.15dB. The gain at fCUTOFF is -1dB and the filter’s stopband attenuation is 80dB at 2.3fCUTOFF . Linear phase operation is also available with a clock-to-cutoff frequency ratio of 100:1 when pin 8 is connected to ground.

The LTC1066-1 is available in an 18-pin SO Wide package..

Applications

* Instrumentation

* Data Acquisition Systems

* Anti-Aliasing Filters

* Smoothing Filters

* Audio Signal Processing

* DC Gain Linearity: 14 Bits

* Maximum DC Offset: ±1.5mV

* DC Offset TempCo: 7µV/°C

* Device Fully Tested at fCUTOFF = 80kHz

* Maximum Cutoff Frequency: 120kHz (VS = ±8V)

* Drives 1kΩ Load with 0.02% THD or Better

* Signal-to-Noise Ratio: 90dB

* Input Impedance: 500MΩ

* Selectable Elliptic or Linear Phase Response

* Operates from Single 5V up to ±8V Power Supplies

* Available in an 18-Pin SO Wide Package