2013 I experimented in the VHF area with IQ mixer. The LT5517 chip is a 40MHz to 900MHz quadrature demodulator where an VHF signal is directly converted into I and Q baseband signals with a bandwidth up to 130MHz. The LT5517 incorporates balanced I and Q mixers, LO buffer amplifiers and a precision, broadband quadrature generator derived from a divide-by-two circuit. But the LT5517 comes in a 16-lead (4mm x 4mm) plastic QFN case with an exposed pad (pin 17) as GND. That is not a good for an amateur do-it-yourselfer. My solution is a upside down chip soldering, I already had AD9951 practice with that...
 LT5517 upside down |
 Exposed pad |
 RF Shield |
 Experimnetal board |
