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