LT5546 Datasheet | Linear Technology

LT5546 40MHz to 500MHz VGA and I/Q Demodulator with 17MHz Baseband Bandwidth Features s s s s DESCRIPTIO s s s s s s s s s s 17MHz I/Q Lowpass Output Noise Filters Wide Range 1.8V to 5.25V Supply Voltage Frequency Range: 40MHz to 500MHz THD < 0.14% (- 57d Bc) at 800m VP-P Differential Output Level IF Overload Detector Log Linear Gain Control Range: - 7d B to 56d B Baseband I/Q Amplitude Imbalance: 0.2d B Baseband I/Q Phase Imbalance: 0.6° 7.8d B Noise Figure at Max Gain Input IP3 at Low Gain: - 1d Bm Low Supply Current: 24m A Low Delay Shift Over Gain Control Range: 2ps/d B Outputs Biased Up While in Standby 16-Lead QFN 4mm × 4mm Package with Exposed Pad U APPLICATIO S s s s s GPS IF Receivers Satellite IF Receivers VHF/UHF Receivers Wireless Local Loop 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. It 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 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-d B 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 ponents. The - 3d B 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. , LTC and LT are registered trademarks of Linear Technology Corporation. TYPICAL APPLICATIO 280MHz IF INPUT L1 15n H C3 10p F L2 15n H IF + C2 1µF C1 1n F VCC 1.8V - 25 - 30 -...