TQ5635 Ver la hoja de datos (PDF) - TriQuint Semiconductor

Número de pieza

componentes Descripción

Fabricante

TQ5635

3 V PCS LNA/Mixer Receiver IC

TriQuint Semiconductor 

TQ5635

Data Sheet

Figure 10: Suggested LO Tuning Response

A first approximation to the needed inductor can be found by

the following equation:

1

L = ---------------- - 1nH where C=1.5pF

C (2*pi*F)2

It is likely that when the design is prototyped, the needed

inductance will fall between two standard inductor values. It is

advised to use a slightly larger inductor and then use the

bypass capacitor for fine tuning. When using this method it is

important to isolate the tuning inductor/bypass cap node from

the Vdd bus, since loading on the bus can affect tuning. A

resistor of 3.3ohm to 20ohm has been found to work well for

this purpose (R2).

Figure 11 shows the recommended test setup for tuning the

TQ5635 LO buffer. A network analyzer is set to the center of

the LO band +/- 300Mhz, with an output power of –4dBm. It is

important to set the frequency range to be quite a bit wider

than the LO band, so that the shape of the tuning curve can

be seen. A two port calibration is performed and the analyzer

is set to monitor S21. Port 1 of the analyzer is connected to

the LO port of the TQ5635, while Port 2 is connected via cable

to a short length of semi-rigid coaxial probe. The center of the

probe should protrude 1 to 2 mm beyond the ground shield.

The end of the probe with the exposed center conductor is

held close to the LO tuning inductor.

For additional information and latest specifications, see our website: www.triquint.com

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