STW81102ATR STMicroelectronics, STW81102ATR Datasheet - Page 25

• 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

STW81102
5.9
5.9.1
Table 9.
Output stage
The differential output signal of the synthesizer can be selected by software among three
different signal paths (Direct, Divider by 2 and Divider by 4) providing multi-band capability.
The selection of the output stage is done by programming properly the PD[4:0] bits.
The output stage is an open-collector structure which is able to meet different requirements
over the desired output frequency range by proper connections on the PCB. Refer to
Chapter 8: Application information
Output Buffer control mode
This control mode allows to enable/disable the output stage by a hardware control pin
(EXT_PD, pin#23) while the PLL stays locked at the desired frequency; in such a way a very
fast switching time is achieved.
This feature can be useful in designing a ping-pong architecture saving the cost of an
external RF switch.
The function of pin#23 (EXT_PD) is set with the OUTBUF_CTRL_EN bit as shown in
Table 10.
Table 10.
OUTBUF_CTRL_EN
PLL_A[1:0]
00
01
10
11
0
1
VCO B performances versus amplitude setting (freq=4.3GHz)
EXT_PD pin function setting
Differential voltage swing
Device hardware power down
Output Buffer control
Function of the EXT_PD pin
(Vp)
1.1
1.3
1.9
2.1
for more details on PCB connections.
Current consumption
EXT_PD = 0V
EXT_PD = 3.3V
EXT_PD = 0V
EXT_PD = 3.3V
(mA)
11
14
20
22
EXT_PD pin settings
PN @1MHz (dBc/Hz)
Circuit description
Device ON
Device OFF
Output Stage ON
Output Stage OFF
-127.5
-124
-125
-128
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