ADRF6702 Analog Devices, Inc., ADRF6702 Datasheet - Page 17

• Manufacturer Part Number: ADRF6702
• Description: 1550 Mhz To 2150 Mhz Quadrature Modulator With Integrated Fractional-n Pll And Vco
• Manufacturer: Analog Devices, Inc.

DB23
DB23
0
0
Preliminary Technical Data
REGISTER 7 EXTERNAL VCO ENABLE
With R6[2:0] set to 111, the External VCO Control register is
programmed as shown in figure 9.
The External VCO Enable bit allows the use of an external VCO
in the PLL instead of the internal VCO. This can be
advantageous in cases where the internal VCO is not capable of
providing the desired frequency or where the internal VCO’s
External
External
Enable
Enable
XVCO
XVCO
DB22
DB22
VCO
VCO
XVCO External VCO Enable
XVCO External VCO Enable
0
0
1
1
Internal VCO (default)
Internal VCO (default)
External
External
DB21
DB21
V
V
0
0
DB20
DB20
CO
CO
0
0
DB19
DB19
0
0
DB18
DB18
0
0
DB17
DB17
0
0
DB16
DB16
0
0
DB15
DB15
0
0
Figure 12. VCO Control and Enable (R7)
DB14
DB14
0
0
DB13
DB13
0
0
Rev. PrE | Page 17 of 18
DB12
DB12
0
0
DB11
DB11
0
0
DB10
DB10
phase noise is higher than desired. By setting this bit (DB22) to
1, and setting Register 6, bits DB15-DB10 to 0, the internal
VCO is disabled, and the output of an external VCO can be fed
into the part differentially on pins 38,37 (LOP,LON). Since the
loop filter is already external, the output of the loop filter simply
needs to be connected to the external VCO’s tuning voltage pin.
0
0
DB9
DB9
0
0
DB8
DB8
0
0
DB7
DB7
0
0
DB6
DB6
0
0
DB5
DB5
0
0
DB4
DB4
0
0
DB3
DB3
0
0
C3(1)
C3(1)
DB2
DB2
Control Bits
Control Bits
ADRF6702
C2(1)
C2(1)
DB1
DB1
C1(1)
C1(1)
DB0
DB0