TQ3132 Просмотр технического описания (PDF) - TriQuint Semiconductor
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TQ3132 Datasheet PDF : 10 Pages
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Table 1. TQ3132 Control lines C2, C3
TQ3132 LNA Mode C2
C3
CDMA
0
0
High Gain (HG)
1
0
Bypassed
1
1
AMPS
0
1
Gain Control via Pin 4 Inductance
The source connection of the LNA cascode is brought out
separately through pin 4. This allows external degeneration of
the cascode by adding a small amount of PC board trace
inductance to pin 4. Thus some increase in IIP3 can be made
while reducing LNA gain. The total amount of inductance
present at the source of the cascode is equal to the bond wire
plus package plus external inductances. One should generally
use an external inductance such that gain in the High Gain
mode = 13.5dB. On the evaluation board the total PCB trace
inductance at pin 4 is approximately 2.57nH. In order to achieve
the desire gain, this board inductor should be shorted half way
of its total length which is equivalent to about 1.55nH.
Board Layout Recommendations
All ground pins should be kept close to the IC and have its own
via to the ground plane to minimize inductance. Most PC boards
for portable applications have thin dielectric layers and very
narrow line width which increase the board parasitic capacitance
and inductance. To minimize these effects when implementing a
matching network, it is recommended to relieve the ground
underneath pads carrying RF signals whenever possible.
RF input power levels for accurate test results
Because the CDMA devices have a number of gain states, it
important to make sure that IP3 measurements are not taken in
a state of compression. Additionally, using too low of a power
puts the IMD products too close to the noise floor for accurate
results. Additionally, the LNA in the bypass mode have OIP3 of
around 30dBm, which is higher than the IIP3 of common
spectrum analyzers in their preset configuration. We have
TQ3132
Data Sheet
found that setting the spectrum analyzer attenuator to 20dB
allows for accurate measurement in that mode, and in all the
other modes.
TQ3132 Noise and S-Parameters Data
The following noise and S-parameter data was obtained using
TriQuint’s evaluation board. This information is intended to be
used as a guide to synthesize the LNA tuning network and find a
compromise between noise figure and gain for all modes.
Table 2. Gamma Opt analysis for TQ3132 High Gain Mode
Freq
(MHz)
Γ Opt
< Angle Fmin
(dB)
R noise
700
0.53 32.8
1.1
24.15
880
0.52 41.5
1.0
19.03
1000
0.49 42.6
1.1
17.98
Table 3. Gamma Opt analysis for TQ3132 AMPS Mode
Freq
(MHz)
Γ Opt
< Angle Fmin
(dB)
R noise
700
0.62 33.5
1.3
33.5
880
0.56 40.2
1.2
26.4
1000
0.53 41.9
1.3
25.1
For additional information and latest specifications, see our website: www.triquint.com
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