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參數資料
| 型號： | ADF4153 |
| 廠商： | Analog Devices, Inc. |
| 英文描述： | Fractional-N Frequency Synthesizer |
| 中文描述： | 分數N頻率合成器 |
| 文件頁數： | 20/24頁 |
| 文件大小： | 354K |
| 代理商： | ADF4153 |
ADF4153
When enabled, it activates every time the user programs
Register R0 to set a new output frequency. However, if a cycle
slip occurs in the settling transient after the phase RESYNC
operation, the phase RESYNC is lost. This can be avoided by
delaying the RESYNC activation until the locking transient is
close to its final frequency. This is done by rewriting to R1 after
R1 has been set up as normal. Setting load control [DB23]
allows this. When set, instead of determining the fractional
denominator, the MOD bits [M12 to M1] are used to set a time
interval from when the new channel is programmed to the time
the RESYNC is activated. This is called the delay. Its value
should be programmed to set a time interval that is at least as
long as the RF PLL lock time.
Rev. A | Page 20 of 24
For example, if REF
IN
= 26 MHz and MOD = 130 to give
200 kHz output steps (f
RES
), and the RF loop has a settling
time of 150 μs, then delay should be programmed to 3,900,
as 26 MHz × 150 μs = 3,900.
If the application requires the delay to be greater than 4095, the
RESYNC bits should be increased. For example, if the lock time
above is 1.5 ms, the delay should be programmed to 26 MHz ×
1.5 ms = 39,000. In this case, program M12 to M1 to 3,900 and
program S4 to S1 to 10. The delay is 3,900 × 10 = 39,000.
SPURIOUS SIGNALS—PREDICTING WHERE THEY
WILL APPEAR
Just as in integer-N PLLs, spurs appear at PFD frequency offsets
from the carrier. In a fractional-N PLL, spurs also appear at
frequencies equal to the RF
OUT
channel step resolution (f
RES
).
The third-order fractional interpolator engine of the ADF4153
may also introduce subfractional spurs. If the fractional
denominator (MOD) is divisible by 2, spurs appear at 1/2 f
RES.
If
the fractional denominator (MOD) is divisible by 3, spurs
appear at 1/3 f
RES.
Harmonics of all spurs mentioned will also
appear. With the lowest spur mode enabled, the fractional and
subfractional spurs is attenuated dramatically. The worst-case
spurs appear when the fraction is programmed to (1/MOD).
For example, in a GSM 900 MHz system with a 26 MHz PFD
frequency and an RF
OUT
channel step resolution (f
RES
) of 200
kHz, the MOD = 130. PFD spurs appear at 26 MHz offset, and
fractional spurs appear at 200 kHz offset. Since MOD is
divisible by 2, subfractional spurs are also present at 100 kHz
offset.
FILTER DESIGN—ADISIMPLL
A filter design and analysis program is available to help the user
to implement PLL design. Visit
www.analog.com/pll
for a free
download of the ADIsimPLL software. The software designs,
simulates, and analyzes the entire PLL frequency domain and
time domain response. Various passive and active filter
architectures are allowed. REV. #2 of ADIsimPLL allows analysis
of the ADF4153.
INTERFACING
The ADF4153 has a simple SPI compatible serial interface for
writing to the device. SCLK, SDATA, and LE control the data
transfer. When LE (latch enable) is high, the 22 bits that have
been clocked into the input register on each rising edge of
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 for the device is
909 kHz or one update every 1.1 μs. This is more than adequate
for systems that have typical lock times in the hundreds of
microseconds.
ADuC812 Interface
Figure 21 shows the interface between the ADF4153 and the
ADuC812 MicroConverter. Since 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 ADF4153 needs a
24-bit word, which is accomplished by writing three 8-bit bytes
from the MicroConverter to the device. After the third byte is
written, the LE input should be brought high to complete the
transfer.
When operating in the mode described, 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
180 kHz.
ADuC812
ADF4153
SCLOCK
SCLK
SDATA
LE
MUXOUT
(LOCK DETECT)
MOSI
I/O PORTS
0
Figure 21. ADuC812 to ADF4153 Interface
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| ADF4153ABCPZ | 制造商:Analog Devices 功能描述:SINGLE RF F-N PLL 制造商:Analog Devices 功能描述:SINGLE RF F-N PLL - Trays 制造商:Analog Devices 功能描述:IC PLL FREQ SYNTHESIZER 20-LFCSP 制造商:Analog Devices 功能描述:IC FREQ SYNTHESIZER 4GHZ 20 制造商:Analog Devices 功能描述:IC, FREQ SYNTHESIZER, 4GHZ, 20LFCSP 制造商:Analog Devices Inc. 功能描述:Phase Locked Loops - PLL Single RF F-N PLL 制造商:Analog Devices 功能描述:PLL SYNTHESIZER, FREQUENCY, 4GHZ, LFCSP-20; PLL Type:Frequency Synthesis; Frequency:4GHz; Supply Current:20mA; Supply Voltage Min:2.7V; Supply Voltage Max:3.3V; Digital IC Case Style:LFCSP; No. of Pins:20; Package / Case:20-LFCSP 制造商:Analog Devices 功能描述:IC, FREQ SYNTHESIZER, 4GHZ, 20LFCSP; Synthesizer Type:Frequency; Frequency:4GHz; Supply Voltage Min:2.7V; Supply Voltage Max:3.3V; Supply Current:20mA; Digital IC Case Style:LFCSP; No. of Pins:20; Operating Temperature Min:-40C; ;RoHS Compliant: Yes 制造商:Analog Devices 功能描述:PLL SYNTHESIZER, FREQUENCY, 4GHZ, LFCSP-20; PLL Type:Frequency Synthesis; Frequency:4GHz; Supply Current:20mA; Supply Voltage Min:2.7V; Supply Voltage Max:3.3V; Digital IC Case Style:LFCSP; No. of Pins:20; Package / Case:20-LFCSP ;RoHS Compliant: Yes |
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| ADF4153ABRUZ | 制造商:Analog Devices 功能描述:SINGLE RF F-N PLL - Rail/Tube 制造商:Analog Devices 功能描述:ngle RF F-N PLL |
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