STW81100AT-1 STMicroelectronics, STW81100AT-1 Datasheet - Page 22

• Manufacturer Part Number: STW81100AT-1
• Description: IC SYNTHESIZER MULTI RF 28VFQFPN
• Manufacturer: STMicroelectronics
• Type: Frequency Synthesizerr

Specifications of STW81100AT-1

• Pll: Yes
• Input: Clock, Crystal
• Output: Clock, Crystal
• Number Of Circuits: 1
• Ratio - Input:output: 3:2
• Differential - Input:output: No/No
• Frequency - Max: 4.4GHz
• 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: 4.4GHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

STW81100
proximately 2dBm output power over the whole band. This topology 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
could be easily adjusted to be tuned at the frequency of interest.
Figure 24. LC lumped balun and matching network
The 6.8nH 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 1.1nH series inductors are used to resonate the parasitic
capacitance of the chip.
For an 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, which allows for a more broadband matching and balanced to unbalanced con-
version, is shown in
Figure 25. Microstrip line and lumped matching network
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RFOUTP
RFOUTN
L=500mil
L=500mil
W=20mil
W=20mil
Figure 25
RF
RF
OUTP
OUTN
V
CC
.
1.1nH
1.1nH
C=0.4pF
L=300mil
W=20mil
L=300mil
3.6nH
W=20mil
0.3pF
0.3pF
3.6nH
VCC
VCC
6.8nH
L=2.2nH
L=2.2nH
C=0.8pF
C=0.8pF
0.7pF
0.7pF
3.5nH
2:1
50 O hm
50Ohm load