EVAL-ADF4360-2EB1 Analog Devices Inc, EVAL-ADF4360-2EB1 Datasheet - Page 21

• Manufacturer Part Number: EVAL-ADF4360-2EB1
• Description: BOARD EVAL EB1 FOR ADF4360-2
• Manufacturer: Analog Devices Inc

Specifications of EVAL-ADF4360-2EB1

• Module/board Type: Evaluation Board
• For Use With/related Products: ADF4360-2
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

FIXED FREQUENCY LO
Figure 18 shows the ADF4360-2 used as a fixed frequency LO at
2.0 GHz. The low-pass filter was designed using ADIsimPLL
for a channel spacing of 8 MHz and an open-loop bandwidth of
40 kHz. The maximum PFD frequency of the ADF4360-2 is
8 MHz. Because using a larger PFD frequency allows the use of a
smaller N, the in-band phase noise is reduced to as low as
possible, –99 dBc/Hz. The 40 kHz bandwidth is chosen to be just
greater than the point at which the open-loop phase noise of the
VCO is –99 dBc/Hz, thus giving the best possible integrated
noise. The typical rms phase noise (100 Hz to 100 kHz) of the LO
in this configuration is 0.3°. The reference frequency is from a
16 MHz TCXO from Fox; thus, an R value of 2 is programmed.
Taking into account the high PFD frequency and its effect on the
band select logic, the band select clock divider is enabled. In this
case, a value of 8 is chosen. A very simple pull-up resistor and dc
blocking capacitor complete the RF output stage.
INTERFACING
The ADF4360 family has a simple SPI®-compatible serial
interface for writing to the device. CLK, DATA, and LE control
the data transfer. When LE goes high, the 24 bits that are
clocked into the appropriate register on each rising edge of CLK
are transferred to the appropriate latch. See Figure 2 for the
timing diagram and Table 5 for the latch truth table.
The maximum allowable serial clock rate is 20 MHz. This
means that the maximum update rate possible is 833 kHz or
one update every 1.2 μs. This is certainly more than adequate
for systems that have typical lock times in hundreds of
microseconds.
801BE-160
16MHz
FOX
1nF
10µF
1nF
4.7kΩ
1nF
51Ω
14
16
17
18
19
12
13
CPGND
C
REF
CLK
DATA
LE
C
R
1
V
V
N
C
SET
VCO
VCO
6
Figure 18. Fixed Frequency LO
IN
3
DV
8
21
DD
AGND
9
ADF4360-2
AV
V
VDD
10 11
2
DD
CE MUXOUT
23
22
DETECT
LOCK
DGND RF
15
20
RF
V
OUT
OUT
TUNE
CP
A
B
24
7
4
5
V
51Ω
3.3nF
VCO
51Ω
560Ω
18.0nF
100pF
100pF
Rev. B | Page 21 of 24
ADuC812 Interface
Figure 19 shows the interface between the ADF4360 family and
the ADuC812 MicroConverter®. Because the ADuC812 is based
on an 8051 core, this interface can be used with any 8051-based
microcontroller. The MicroConverter is set up for SPI master
mode with CPHA = 0. To initiate the operation, the I/O port
driving LE is brought low. Each latch of the ADF4360 family
needs a 24-bit word, which is accomplished by writing three
8-bit bytes from the MicroConverter to the device. When the
third byte is written, the LE input should be brought high to
complete the transfer.
I/O port lines on the ADuC812 are also used to control power
down (CE input) and detect lock (MUXOUT configured as lock
detect and polled by the port input). When operating in the
described mode, the maximum SCLOCK rate of the ADuC812
is 4 MHz. This means that the maximum rate at which the
output frequency can be changed is 166 kHz.
ADSP-21xx Interface
Figure 20 shows the interface between the ADF4360 family and
the ADSP-21xx digital signal processor. The ADF4360 family
needs a 24-bit serial word for each latch write. The easiest way
to accomplish this using the ADSP-21xx family is to use the
autobuffered transmit mode of operation with alternate
framing. This provides a means for transmitting an entire block
of serial data before an interrupt is generated.
Set up the word length for 8 bits and use three memory
locations for each 24-bit word. To program each 24-bit latch,
store the 8-bit bytes, enable the autobuffered mode, and write to
the transmit register of the DSP. This last operation initiates the
autobuffer transfer.
ADSP-21xx
ADuC812
I/O PORTS
I/O PORTS
SCLOCK
SCLOCK
Figure 20. ADSP-21xx to ADF4360-x Interface
Figure 19. ADuC812 to ADF4360-x Interface
MOSI
MOSI
TFS
SDATA
SDATA
SCLK
LE
CE
MUXOUT
(LOCK DETECT)
SCLK
LE
CE
MUXOUT
(LOCK DETECT)
ADF4360-x
ADF4360-x
ADF4360-2