AD9139(Rev0) データシートの表示（PDF） - Analog Devices
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AD9139 Datasheet PDF : 56 Pages
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Data Sheet
PLL SETTINGS
The PLL circuitry requires three settings to be programmed to
their nominal values. The PLL values listed in Table 20 are the
recommended settings for these parameters.
Table 20. PLL Settings
PLL SPI Control Register
PLL Loop Bandwidth
PLL Charge Pump Current
PLL Cross Point Control Enable
Register
Address
0x14[7:5]
0x14[4:0]
0x15[4]
Optimal Setting
(Binary)
111
00111
0
CONFIGURING THE VCO TUNING BAND
The PLL VCO has a valid operating range from approximately
1.03 GHz to 2.07 GHz covered in 64 overlapping frequency
bands. For any desired VCO output frequency, there may be
several valid PLL band select values. See Figure 44 for the
frequency bands of a typical device. Device-to-device variations
and operating temperature affect the actual band frequency
range. Therefore, it is necessary to determine the optimal PLL
band select value for each individual device.
AUTOMATIC VCO BAND SELECT
The device has an automatic VCO band select feature on chip.
Using the automatic VCO band select feature is a simple and
reliable method of configuring the VCO frequency band.
Enable this feature by starting the PLL in manual mode and then
placing the PLL in autoband select mode by setting Register 0x12
to a value of 0xC0 and then to a value of 0x80. When these
values are written, the device executes an automated routine
that determines the optimal VCO band setting for the device.
The setting selected by the device ensures that the PLL remains
locked over the full −40°C to +85°C operating temperature
range of the device without further adjustment. The PLL
remains locked over the full temperature range even if the
temperature during initialization is at one of the temperature
extremes.
AD9139
61
57
53
49
45
41
37
33
29
25
21
17
13
9
5
1
950
1150
1350
1550
1750
VCO FREQUENCY (MHz)
1950
2150
Figure 44. PLL Lock Range for a Typical Device
MANUAL VCO BAND SELECT
The device includes a manual band select mode (PLL auto
manual enable, Register 0x12[6] = 1) that lets the user select the
VCO tuning band. In manual mode, the VCO band is set
directly with the value written to the manual VCO band bits
(Register 0x12[5:0]).
PLL ENABLE SEQUENCE
To enable the PLL in automatic or manual mode properly, the
following sequence must be followed:
Automatic Mode Sequence
1. Configure the loop divider and the VCO divider registers
for the desired divide ratios.
2. Set 00111 to PLL charge pump current and 111 to PLL loop
bandwidth for the best performance. Register 0x14 = 0xE7
(default).
3. Set the PLL mode to manual using Register 0x12[6] = 1.
4. Enable the PLL using Register 0x12[7] = 1.
5. Set the PLL mode to automatic using Register 0x12[6] = 0.
Manual Mode
1. Configure the loop divider and the VCO divider registers
for the desired divide ratios.
2. Set 00111 to PLL charge pump current and 111 to PLL loop
bandwidth for the best performance. Register 0x14 = 0xE7
(default).
3. Select the desired band using Register 0x12[5:0].
4. Set the PLL mode to manual using Register 0x12[6] = 1.
5. Enable the PLL using Register 0x12[7] = 1.
Rev. 0 | Page 35 of 56
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