STW82101B Datasheet, PDF (61/68 Pages) STMicroelectronics – RF down converter with embedded integer-N synthesizer

STW82101B
Application information
11.5
External VCO standard mode operation
The STW82101B can be used in Ext VCO Mode for both RX path and TX observation path
(RX Chain ON, Synthesizer ON, EXT VCO/LO buffer ON and with an external VCO).
In such a case the 10-bit internal DAC can drive an external PIN diode attenuator in order to
calibrate the signal level at the input of the device.
Figure 29. External VCO standard mode operation
RF_IN2
I_PINDRV1
I_PINDRV2
RF_IN
RF_IN
RF_VSS
RF_CT
5V
MIXDRV_CT
DAC
MIX
DRV
STW82101B
PLL
EXT
LO/VCO
BUF
EXTVCO_INP
EXTVCO_INN
EXTERNAL
VCO
IF AMP
DBUS
5V
IF_OUTP
IF_OUTN
DBUS_SEL
SDA/DATA
SCL/CLK
LOAD
4:1 IF_OUT
50 Ω
BUF
REF_CLK
PFD
UP
CHP
DN
LOCK_DET
REXT_CP
ICP
Doc ID 018503 Rev 3
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