AD6458 Datasheet | Analog Devices

a Features Fully pliant with Standard and Enhanced GSM Specification - 12 d Bm Input 1 d B pression Point - 2 d Bm Input Third Order Intercept 10 d B SSB Noise Figure (330 ⍀) DC- 400 MHz RF and LO Bandwidths Linear IF Amplifier Linear-in-d B 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 m A 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 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 d Bm input-referred 1 d B pression point and a - 2 d Bm 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 d Bm. The gain control input accepts an external gain-control voltage input from an external AGC detector or a DAC. It provides an 80 d B gain range with 27 m V/d B gain scaling. The I and Q demodulators provide inphase and quadrature baseband outputs to interface with Analog Devices’ AD7013 (IS54, TETRA, MSAT) and AD7015 and AD6421 (GSM, DCS1800, PCS1900) baseband converters. An onboard quadrature VCO which is externally phase-locked to the IF signal drives the I and Q demodulators. This locked reference signal is normally provided by an external VCTCXO under the control of the radio’s digital processor. The AD6458 can also...