GENERAL DESCRIPTION

The AD8346 is a silicon RFIC I/Q modulator for use from 0.8 GHz to 2.5 GHz. Its excellent phase accuracy and amplitude 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 converters 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 a 50 Ω load.

FEATURES

High accuracy

1 degree rms quadrature error @ 1.9 GHz

0.2 dB I/Q amplitude balance @ 1.9 GHz

Broad frequency range: 0.8 GHz to 2.5 GHz

Sideband suppression: −46 dBc @ 0.8 GHz

Sideband suppression: −36 dBc @ 1.9 GHz

Modulation bandwidth: dc to 70 MHz

0 dBm output compression level @ 0.8 GHz

Noise floor: −147 dBm/Hz

Single 2.7 V to 5.5 V supply

Quiescent operating current: 45 mA

Standby current: 1 μA

16-lead TSSOP

APPLICATIONS

Digital and spread spectrum communication systems

Cellular/PCS/ISM transceivers

Wireless LAN/wireless local loop

QPSK/GMSK/QAM modulators

Single-sideband (SSB) modulators

Frequency synthesizers

Image reject mixer