A micropower CMOS, direct-conversion, VLF receiver chip formagnetic-field wireless applications

摘要

A micropower CMOS, direct-conversion VLF receiver is described fornreceiving low-level magnetic fields from resonant sensors. Thensingle-chip, PLL-synthesized receiver covers a frequency range of 10-100nkHz and provides both analog and digital 9-bit I and Q baseband outputs.nLateral bipolar transistors are utilized for low flicker noise and lownDC offsets, and special attention is given to isolating the internalnlocal oscillator signals from the low-level RF input (0.3 μV noisenfloor, 300 Hz BW). The 100% duty-cycle receiver, intended fornlong-battery life wireless applications, operates at 360 μW from an6-V battery