AD6432

a FEATURES Fully Compliant with Standard and Enhanced GSM Specification DC-350 MHz RF Bandwidths 80 dB Gain Control Range I/Q Modulation and Demodulation Onboard Phase Locked Tunable Oscillator On-Chip Noise Roofing IF Filters Ultralow Power Design 2.7 V–3.6 V Operating Voltage User-Selectable Power-Down Modes Small 44-Lead TQFP Package Interfaces Directly with AD20msp410 and AD20msp415 GSM Baseband Chipsets APPLICATIONS I/Q Modulated Digital Wireless Systems GSM Mobile Radios GSM PCMCIA Cards GSM 3 V Transceiver IF Subsystem AD6432 FUNCTIONAL BLOCK DIAGRAM BP SAW PLO IF SYNTH RF SYNTH PA AD6432 OP AMP GENERAL DESCRIPTION The AD6432 IF IC provides the complete transmit and receive IF signal processing, including I/Q modulation and demodulation, necessary to implement a digital wireless transceiver such as a GSM handset. The AD6432 may also be used for other wireless TDMA standards using I/Q modulation. The AD6432’s receive signal path is based on the proven architecture of the AD607 and the AD6459. It consists of a mixer, gain-controlled amplifiers, integrated roofing filter and I/Q demodulators based on a PLL. The low noise, high-intercept variable-gain mixer is a doubly-balanced Gilbert-cell type. It has a nominal –13 dBm input-referred 1 dB compression point and a 0 dBm input-referred third-order intercept. The gain-control input accepts an external control voltage input from an external AGC detector or a DAC. It provides an 80 dB gain range with 27.5 mV/dB gain ...