Linear Technology has introduced a family of five single and dual amplifying active low-pass filters that can drive ADCs.

LTC6603 is a dual matched programmable 9th order switched capacitor linear-phase filter and ADC driver, with cut-off to 2.5MHz. Gain and cut-off are adjustable via a serial SPI port or can be fixed by pin-strapping. Fine frequency control over a 100:1 range can be implemented using an external DAC to vary the device’s master reference clock.

Applications include baseband filtering for I/Q demodulators in: CDMA-2000, W-CDMA and LTE femto-cell basestations, as well as repeaters, RFID readers, imaging, and sonar scan receivers. Package is 4x4mm 24-lead QFN.

LTC6601-1, is laser-trimmed 0.5% tolerance with configurable bandwidth from 5 to 28MHz. This filter has a 2nd order linear-phase Butterworth response, and it has differential inputs and outputs. On-chip resistors and capacitors control frequency and Q, but are pinned out allowing users to set other combinations of filter response and gain. Package is 4x4mm 20lead QFN.

LTC6605-7, -10 and -14, are fixed frequency, 2nd order linear-phase dual matched filters with bandwidths of 7, 10 and 14MHz, respectively. Each filter pair is tested and guaranteed to offer matching of phase and gain.

These are intended for I/Q demodulator channel filtering in WiMAX and broadband wireless access equipment including point-to-point microwave links. The matching also suits multi-channel signal processing and pre-filtering for high speed ADCs. Packaging is 6x3mm, 22 lead DFN.

All filters are available in two grades: 0-70ºC, and -40 to 85ºC.

More information: www.linear.com