STW81102ATR STMicroelectronics, STW81102ATR Datasheet - Page 42

• Manufacturer Part Number: STW81102ATR
• Description: IC SYNTHESIZER MULTI RF 28VFQFPN
• Manufacturer: STMicroelectronics
• Type: Frequency Synthesizerr

Specifications of STW81102ATR

• Pll: Yes
• Input: Clock, Crystal
• Output: Clock, Crystal
• Number Of Circuits: 1
• Ratio - Input:output: 3:2
• Differential - Input:output: No/No
• Frequency - Max: 4.65GHz
• Divider/multiplier: Yes/No
• Voltage - Supply: 3 V ~ 3.6 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 28-VFQFN, 28-VFQFPN
• Frequency-max: 4.65GHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Application information
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Alternatively, you can combine the two outputs in other ways. A first topology for the direct
output (3 GHz to 4.65 GHz) is suggested in
balun and a matching network to adapt the output to a 50 Ω load. The two LC networks shift
output signal phase of -90° and +90°, thus combining the two outputs. This topology,
designed for a center frequency of 4 GHz, is intrinsically narrow-band since the LC balun is
tuned at a single frequency. If the application requires a different sub-band, the LC combiner
can be easily tuned to the frequency of interest.
Figure 29. LC lumped balun and matching network (MATCH_LC_LUMP_4G.dsn)
The 1.9 nH shunt inductor works as a DC feed for one of the open collector terminals as well
as a matching element along with the other components. The 1.9 nH series inductors are
used to resonate the parasitic capacitance of the chip.
For optimum output matching, it is recommended to use 0402 Murata or AVX capacitors and
0403 or 0604 HQ Coilcraft inductors. It is also advisable to use short interconnection paths
to minimize losses and undesired impedance shift.
An alternative topology that permits a more broadband matching as well as balanced to
unbalanced conversion, is shown in
RF
RF
OUTP
OUTN
50 ohm
50 ohm
Vcc
Vcc
1.9nH
1.9nH
Figure 30
0.8pF
0.8pF
Figure 29
.
. It basically consists of a simple LC
1.9nH
0.8pF
1.9nH
0.8pF
2.5pF
50 ohm
STW81102