DESCRIPTION
Demonstration circuit 933A is a HF/VHF/UHF Downconverting
Mixer featuring the LT®5512. The RF input
frequency is optimized for 140MHz, and the IF output
frequency range is 0.1MHz to 100MHz. With minor
component changes, the demo board can be configured
for different RF frequencies from 250kHz to
450MHz.
The LT5512 is an active double-balanced mixer IC,
optimized for high linearity HF, VHF and UHF applications.
The IC includes an integrated LO buffer amplifier
to drive the mixer and an RF buffer amplifier for
improved LO-RF isolation. Internal bias circuits eliminate
the need for precision external resistors and allow
the device to be powered-down using the enable
control (EN) pin.
The externally matched RF and IF ports allow the
mixer to be used at very low frequencies, below
1MHz or up to 3GHz. The differential LO input is designed
for single-ended or a differential drive.
The LT5512 is a high-linearity alternative to passive
diode mixers. Unlike passive mixers, which have conversion
loss and require high LO drive levels, the
LT5512 delivers conversion gain and requires significantly
lower LO drive levels.
Design files for this circuit board are available. Call
the LTC factory.