Register 1-Oscillator Register - Analog Devices ADF7021-V Manual

ADF7021-V
REGISTER 1—OSCILLATOR REGISTER
RESERVED
•
The R_COUNTER and XTAL_DOUBLER relationship is
as follows:
If XTAL_DOUBLER = 0,
XTAL
=
PFD
R _ COUNTER
If XTAL_DOUBLER = 1,
×
XTAL 2
=
PFD
R _ COUNTER
XTAL_
BIAS
RFD1 RF_DIVIDE_BY_2
0 OFF
ON
1
BUFFER_
VE1 IMPEDANCE
0 50Ω
1
HIGH IMPEDANCE
RSET = 3.6kΩ
I (mA)
CP2 CP1
CP
0 0 0.3
0 1 0.9
1 0 1.5
1 1 2.1
Figure 63. Register 1—Oscillator Register Map
Rev. 0 | Page 46 of 60
CLKOUT_
R_COUNTER
DIVIDE
R3
0
0
.
.
.
1
CL4 CL3 CL2
0 0 0
0 0 0
0 0 1
. . .
. . .
. . .
1 1 1
XTAL_
D1 DOUBLER
0 DISABLED
ENABLED
1
X1 XOSC_ENABLE
0 OFF
1 ON
XB2 XB1 XTAL_BIAS
0 0 20µA
0 1 25µA
1 0 30µA
1 1 35µA
•
CLKOUT_DIVIDE is a divided-down and inverted version
of the XTAL and is available on Pin 36 (CLKOUT).
•
Set XOSC_ENABLE high when using an external crystal.
If using an external oscillator (such as TCXO) with CMOS
level outputs into Pin OSC2, set XOSC_ENABLE low. If
using an external oscillator with a 0.8 V p-p clipped sine
wave output into Pin OSC1, set XOSC_ENABLE high.
ADDRESS
BITS
RF R_COUNTER
R2 R1 DIVIDE RATIO
0 1 1
1 0 2
. . .
. . .
. . .
1 1 7
CLKOUT_
CL1 DIVIDE RATIO
OFF
0
1 2
0 4
. .
. .
. .
30
1