AD8346

The AD8346 is a silicon RFIC I/Q modulator for use from 0.8 GHz to 2.5 GHz. Its excellent phase accuracy and ampli-tude balance allow high performance direct modulation to RF.
The differential LO input is applied to a polyphase network phase splitter that provides accurate phase quadrature from 0.8 GHz to 2.5 GHz.  Buffer amplifiers are inserted between two sections of the phase splitter to improve the signal-to-noise ratio. The I and Q outputs of the phase splitter drive the LO inputs of two Gilbert-cell mixers. Two differential V-to-I con- verters connected to the baseband inputs provide the baseband modulation signals for the mixers.

The outputs of the two mixers are summed together at an amplifier which is designed to drive a50 Ω load. ÿThis quadrature modulator can be used as the transmit modula-tor in digital systems such as PCS, DCS, GSM, CDMA, andISM transceivers.  The baseband quadrature inputs are directly modulated by the LO signal to produce various QPSK and QAM formats at the RF output. Additionally, this quadrature modulator can be used with direct digital synthesizers in hybrid phase-locked loops to generate signals over a wide frequency range with millihertz resolution.The AD8346 is supplied in a 16-lead TSSOP package, measur-ing 6.5*5.1 * 1.1 mm.  It is specified to operate over a40°C to +85°C temperature range and 2.7 V to 5.5 V supplyvoltage range. 

The device is fabricated on Analog Devices' high performance 25 GHz bipolar silicon process.