LT5546

Supply Voltage ....................................................... .....5.5V
Differential Voltage Between 2xLO+ and 2xLO..............  4V
IF+, IF ............................................. .500mV to 500mV
IOUT +, IOUT, QOUT+, QOUT .................VCC1.8V to VCC
Operating Ambient Temperature
(Note 2) .......................................................40 to 85
Storage Temperature Range ........................65 to 125
Voltage on Any Pin
Not to Exceed ........................... 500mV to VCC + 500mV

The LT®5546 is a 40MHz to 500MHz monolithic integrated quadrature demodulator with variable gain amplifier (VGA) and 17MHz I/Q baseband bandwidth designed for low voltage operation. The LT5546 supports standards that use a linear modulation format. The chip consists of a VGA, quadrature downconverting mixers and 17MHz lowpass noise filters (LPF). The LO port consists of a divide-by-two stage and LO buffers. The LT5546 IC provides all building blocks for IF downconversion to I and Q baseband signals with a single supply voltage of 1.8V to 5.25V. The VGA gain has a linearin- dB relationship to the control input voltage. Hard-clipping amplifiers at the mixer outputs reduce the recovery time from a signal overload condition. The lowpass filters reduce the out-of-band noise and spurious frequency components. The 3dB corner frequency of the noise filters is approximately 17MHz and has a first order rolloff. The standby mode provides reduced supply current and fast transient response into the normal operating mode when the I/Q outputs are AC-coupled to a baseband chip.