AD6458

a FEATURES Fully Compliant with Standard and Enhanced GSM Specification –12 dBm Input 1 dB Compression Point –2 dBm Input Third Order Intercept 10 dB SSB Noise Figure (330 ⍀) DC–400 MHz RF and LO Bandwidths Linear IF Amplifier Linear-in-dB and Stable over Temperature Voltage Gain Control Quadrature Demodulator Onboard Phase-Locked Quadrature Oscillator Demodulates IFs from 5 MHz to 50 MHz Low Power 9 mA at Midgain 1 ␮ A Sleep Mode Operation 3.0 V to 3.6 V Operation Interfaces to AD7013, AD7015 and AD6421 Baseband Converters 20-Lead SSOP GSM 3 V Receiver IF Subsystem AD6458 FUNCTIONAL BLOCK DIAGRAM LO I RF BPF PLO Q AGC FREF AD6458 GENERAL DESCRIPTION The AD6458 is a 3 V, low power receiver IF subsystem for operation at input frequencies as high as 400 MHz and IFs from 5 MHz up to 50 MHz. It is optimized for operation in GSM, DCS1800 and PCS1900 receivers. It consists of a mixer, IF amplifier, I and Q demodulators, a phase-locked quadrature oscillator, precise AGC subsystem, and a biasing system with external power-down. The low noise, high intercept mixer of the AD6458 is a doubly-balanced Gilbert cell type. It has a nominal –12 dBm input-referred 1 dB compression point and a –2 dBm inputreferred third-order intercept. The mixer section of the AD6458 also includes a local oscillator (LO) preamplifier, which lowers the required LO drive to –16 dBm. The gain control input accepts an external gain-control voltage input from an external AGC detector or a DAC. It provides an 8...