U2794B Datasheet, PDF (13/15 Pages) TEMIC Semiconductors – 1000 MHz Quadrature Demodulator

U2794B
Description of the
Evaluation Board
Board material: epoxy; er = 4.8, thickness = 0.5 mm, transmission lines: Z_O = 50 W
The board offers the following functions:
• Test circuit for the U2794B:
– The supply voltage and the control inputs GC, PC and PU are connected via
a plug strip. The control input voltages can be generated via external
potentiometers; then the inputs should be AC-grounded (time requirements
in burst mode for power up have to be considered).
– The outputs I, IX, Q, QX are DC coupled via an plug strip or can be AC-
connected via SMB plugs for high frequency tests e.g. noise figure or s-
parameter measurement. The Pins II, IIX, QQ, QQX allow user-definable
filtering with 2 external capacitors CII, CQQ.
– The offsets of both channels can be adjusted with two potentimeters or
resistors.
– The LO- and the RF-inputs are AC-coupled and connected via SMB plugs. If
transmission line T3 is connected to the RF-input and AC-grounded at the
other end, gain and noise performance can be improved (input matching to
50 W).
– The complementary RF-input is AC-coupled to GND (CRFX = 1 nF), the
same appears to the complementary LO input (CNLO = 1 nF).
• A calibration part which allows to calibrate an s-parameter analyzer directly to the in-
and output- signal ports of the U2794B.
• For single-ended measurements at the demodulator outputs, two OPs (e.g., AD620
or other) can be con-figured with programmable gain; together with an output-
divider network RD = 450 W to RL = 50 W, direct measurements with 50 W load
impedances are possible at frequencies t < 100 kHz.
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4653C–CELL–06/03