STW81100AT-1 STMicroelectronics, STW81100AT-1 Datasheet - Page 23

• 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

By using this topology the STW81100 is capable to deliver approximately 0dBm to a 50Ω load with a return
loss grater than 10dB over the whole frequency band (3.3 to 4.4GHz).
Those results have been achieved on an FR4 substrate with a thickness of 350um.
For the differential to single ended conversion the 50 to 100Ω - 3.3 to 4.4GHz - Johanson balun is recom-
mended (3700BL15B100).
9.2 Divided by 2 output
If the user's application does not require a balanced to unbalanced conversion, the output matching re-
duces to the simple circuit shown below (
This solution can be easily used to provide one single ended output just terminating the other output at
50Ω with a 3dB power loss.
Figure 26. Differential/single ended output network in the 1.65 - 2.2GHz range
A first solution to combine the differential outputs is the lumped LC type balun tuned in the 2GHz band
(
(1.65GHz to 2.2GHz).
Figure 27. LC lumped balun for the divided by 2 output
Figure 27
). An output power of approximately 2 dBm is delivered to a 50Ω load over the whole band
R F
R F
O U T N
O U T P
V
C C
R F
R F
O U T P
O U T N
3nH
3nH
5 0 O h m
5 0 O h m
Figure 26
5.5nH
5.5nH
1pF
1pF
V
V
C C
C C
).
2 2 n H
2 2 n H
1 0 p F
1 0 p F
1nH
2.8pF
2nH
5 0 O h m
5 0 O h m
50 O hm
STW81100
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