TQ5131 데이터 시트보기 (PDF) - TriQuint Semiconductor
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TQ5131 Datasheet PDF : 14 Pages
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Performance Vs. RBias Ratio (R2/R3) for CDMA
High Gain: (RF_Freq=882MHz, IF_Freq=85MHz,
LO_Freeq=967MHz, PLO=-4dBm, Vdd=2.8)
20
15
10
Gain (dB)
Idd (mA)
IIP3 (dBm)
5
0
8.2/82
18/68
27/62
39/51
R2/R3 (ohms): (Total Rbias ~ 90 ohms)
Figure 4d. Performance Vs. R2/R3 Ratio, Idd = 16mA
Similarly, figure 4e shows gain and input intercept variation
while the current is fixed at 12mA.
Performance Vs. RBias Ratio (R2/R3) for CDMA
High Gain: (RF_Freq=882MHz, IF_Freq=85MHz,
LO_Freq=967MHz, PLO=-4dBm, Vdd=2.8)
16
14
12
10
8
Gain (dB)
Idd (mA)
6
IIP3 (dBm)
4
2
0
-2
0/188.2
8.2/180
27/160
56/130
R2/R3 (ohms) GIC pin: (Totol Rbias ~ 190 ohms)
Figure 4e. Performance Vs. R2/R3 Ratio, Idd = 12.4mA
The normalized impedance at the CDMA IF output is z = 5.0 – j
2.24 Ω. There are several methods of measuring the port
impedance of a device, this particular measurement was taken
on the 5131 demo board by lifting pin 4 of the PCB pad and
soldering the tip of a semirigid probe next to it. Care must be
exercised when grounding the outer conductor of the semirigid
probe. For the measurement to be valid the probe must be
grounded very close to the pin. Before soldering the probe, its
electrical length must be calculated and dialed in the network
analyzer's port extension in order to move the calibration
reference plane right at the tip of the probe. Keep in mind that
the total DC bias resistance at the IF amplifier source must be
TQ5131
Data Sheet
selected before implementing the output match. Significant
changes on this bias resistance might require a new match at
the IF output. When designing the PCB, it is recommended to
place the self bias circuit of the amplifier as close to the pin as
possible to minimize possible loading effects that might cause
an oscillation. Also the shunt capacitor of the IF match should
be grounded close to the IC (see figure 4c).
After designing the IF match in simulation using the given S-
parameters, some adjustment might be needed when
implementing the match on the bench. At this point remember
that the mixer FET must be turned on since the IFA is directly
coupled to it. Also make sure that the LO buffer amplifier is
providing the proper drive level and that any unused ports are
properly terminated. Figure 4 shows the circuit topology and
component values designed for TriQuint's demo board. Verify
that the match has a 2:1 VSWR in all modes. Figure 5 shows a
typical CDMA IF output impedance.
Figure 4c. CDMA IF Output Match (IF = 85MHz)
TQ5131
CDMA
IF
1
8
2
7
3
6
C6=27pF
4
5
C7=27pF
L2=180nH
Vdd
Note: These values were optimized for TriQuint's 5131 Demo
board. The discrepancy between these values and those of the
customer's application may differ due to board and component
parasitics.
Figure 5. CDMA Output Impedance at Pin 4
1.0
CDIF output
0.5
2.0
D Impedance
0.72 @ -8.8
z = 5.0 - j 2.24
y = 0.17 + j 0.07
0.5
1.0
2.0
D
-0.5
-2.0
-1.0
For additional information and latest specifications, see our website: www.triquint.com
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