STW81101AT STMicroelectronics, STW81101AT Datasheet - Page 25

• Manufacturer Part Number: STW81101AT
• Description: IC SYNTHESIZER MULTI RF 28VFQFPN
• Manufacturer: STMicroelectronics
• Type: Frequency Synthesizer (RF)r

Specifications of STW81101AT

• 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
• Number Of Elements: 1
• Pll Input Freq (min): 10MHz
• Pll Input Freq (max): 200MHz
• Operating Supply Voltage (typ): 3.3V
• Operating Temp Range: -40C to 85C
• Package Type: VFQFPN
• Operating Supply Voltage (min): 3V
• Operating Supply Voltage (max): 3.6V
• Operating Temperature Classification: Industrial
• Pin Count: 28
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

STW81101
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 vs. amplitude setting (Freq=4.1 GHz)
EXT_PD pin function setting
voltage swing (Vp)
Device hardware power down
Output Buffer control
Function of the EXT_PD pin
Differential
1.1
1.3
1.9
2.1
for more details on PCB connections.
consumption (mA)
Current
EXT_PD = 0V
EXT_PD = 3.3V
EXT_PD = 0V
EXT_PD = 3.3V
13
15
22
24
EXT_PD pin settings
Circuit description
Device ON
Device OFF
Output Stage ON
Output Stage OFF
PN at 1 MHz
(dBc/Hz)
-127.5
-123
-125
-128
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