Dual Matched 14MHz Filter with Low Noise, Low Distortion Differential Amplifier

The LTC6605-14 contains two independent, fully differential amplifiers configured as matched 2nd order 14MHz lowpass filters. The f–3dB of the filters is adjustable in the range of 12.4MHz to 20MHz and 25MHz.

The internal op amps are fully differential, feature very low noise and distortion, and are compatible with 16-bit dynamic range systems. The inputs can accept single ended or differential signals. An input pin is provided for each amplifier to set the common mode level of the differential outputs.

Internal laser-trimmed resistors and capacitors determine a precise, very well matched (in gain and phase) 14MHz 2nd order filter response. A single optional external resistor per channel can tailor the frequency response for each amplifier.

Three-state BIAS pins determine each amplifier’s power consumption, allowing a choice between shutdown, medium power or full power.

The LTC6605-14 is available in a compact 6mm × 3mm 22-pin leadless DFN package and operates over a –40°C to 85°C temperature range.

Applications

* Broadband Wireless ADC Driver/Filter

* Antialiasing Filter

* Single-Ended to Differential Conversion

* DAC Smoothing Filter

* Zero-IF Direct Conversion Receivers

* Two Matched 14MHz 2nd Order Lowpass Filters with Differential Amplifiers

* Gain Match: ±0.25dB Max, Passband

* Phase Match: ±1.1° Max, Passband

* Single-Ended or Differential Inputs

* < –84dBc Distortion in Passband

* 2.1nV/√Hz Op Amp Noise Density

* Pin-Selectable Gain (0dB/6dB/9.5dB)

* Pin-Selectable Power Consumption (0.35mA/16.2mA/33.1mA)

* Rail-to-Rail Output Swing

* 2.7V to 5.25V Supply Voltage

* Small 22-Pin 6mm × 3mm × 0.75mm DFN Package