The LTC6603 is a dual, matched, programmable lowpass filter for communications receivers and transmitters. The selectivity of the LTC6603, combined with its linear phase, phase matching and dynamic range, make it suitable for filtering in many communications systems. With 1.5° phase matching between channels, the LTC6603 can be used in applications requiring pairs of matched filters, such as transceiver I and Q channels. Furthermore, the differential inputs and outputs provide a simple interface for most communications systems.The sampled data filter does not require an external clock yet its cutoff frequency can be set with a single external resistor with an accuracy of 3.5% or better. The external resistor programs an internal oscillator whose frequency is divided prior to being applied to the filter networks. This allows up to three cutoff frequencies that can be obtained for each external resistor value, allowing the cutoff frequency to be programmed over a range of more than six octaves. Alternatively, the cutoff frequency can be set with an external clock. The filter gain can also be programmed to 1, 2, 4 or 16.The LTC6603 features a low power shutdown mode that can be programmed through the serial interface and is available in a 24-pin 4mm × 4mm QFN package.ApplicationsSmall/Low Cost Basestations:IDEN, PHS, TD-SCDMA, CDMA2000, WCDMA, UMTSLow Cost Repeaters, Radio Links, and Modems802.11x ReceiversJTRS