ADF4154BRUZ Analog Devices Inc, ADF4154BRUZ Datasheet - Page 17

• Manufacturer Part Number: ADF4154BRUZ
• Description: IC FRAC-N FREQ SYNTH 16-TSSOP
• Manufacturer: Analog Devices Inc
• Type: Fractional N Synthesizer (RF)r

Specifications of ADF4154BRUZ

• Pll: Yes
• Input: CMOS
• Output: Clock
• Number Of Circuits: 1
• Ratio - Input:output: 2:1
• Differential - Input:output: Yes/No
• Frequency - Max: 4GHz
• Divider/multiplier: No/Yes
• Voltage - Supply: 2.7 V ~ 3.3 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 16-TSSOP
• Frequency-max: 4GHz
• Pll Type: Frequency Synthesis
• Frequency: 4GHz
• Supply Current: 20mA
• Supply Voltage Range: 2.7V To 5.5V
• Digital Ic Case Style: TSSOP
• No. Of Pins: 16
• Operating Temperature Range: -40°C To +85°C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: EVAL-ADF4154EBZ1 - BOARD EVALUATION FOR ADF4154EB1
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

RF Charge Pump Three-State
This bit (DB3) puts the charge pump into three-state mode when it
is programmed to 1. For normal operation, it should be set to 0.
RF Power-Down
DB4 on the ADF4154 provides the programmable power-down
mode. Setting Bit DB4 to 1 powers down the device. Setting
Bit DB4 to 0 returns the synthesizer to normal operation. While
in software power-down mode, the part retains all information
in its registers. Only when supplies are removed are the register
contents lost.
When a power-down is activated, the following events occur:
1.
2.
3.
4.
5.
6.
Lock Detect Precision (LDP)
When the LDP bit (DB5) is programmed to 0, 24 consecutive
reference cycles of 15 ns must occur before the digital lock detect is
set. When this bit is programmed to 1, 40 consecutive reference
cycles of 15 ns must occur before digital lock detect is set.
Phase Detector Polarity
DB6 sets the phase detector polarity. When the VCO characteristics
are positive, this bit should be set to 1. When they are negative,
this bit should be set to 0.
Charge Pump (CP) Current Setting and CP/2
DB7, DB8, DB9, and DB10 set the charge pump current, which
should be set according to the loop filter design (see Table 9).
REF
Setting the REF
directly to the 4-bit R-counter, which disables the doubler.
Setting the REF
by a factor of 2 before feeding into the 4-bit R-counter. When
the doubler is disabled, the REF
at the PFD input to the fractional synthesizer. When the doubler
is enabled, both the rising and falling edges of REF
active edges at the PFD input.
When the doubler is enabled and the lowest spur mode is
chosen, the in-band phase noise performance is sensitive to the
REF
as 5 dB for the REF
The phase noise is insensitive to the REF
lowest noise mode and in the lowest noise and spur mode. The
phase noise is insensitive to the REF
doubler is disabled.
IN
IN
All active dc current paths are removed.
The synthesizer counters are forced to their load
state conditions.
The charge pump is forced into three-state mode.
The digital lock detect circuitry is reset.
The RF
The input register remains active and capable of loading
and latching data.
Doubler
duty cycle. The phase noise degradation can be as much
IN
input is debiased.
IN
IN
doubler bit to 1 multiplies the REF
doubler bit (DB11) to 0 feeds the REF
IN
duty cycles outside a 45% to 55% range.
IN
falling edge is the active edge
IN
duty cycle when the
IN
duty cycle in the
IN
IN
become
frequency
IN
signal
Rev. A | Page 17 of 24
The maximum allowed REF
enabled is 30 MHz.
NOISE AND SPUR REGISTER, R3
The on-chip noise and spur register is programmed by setting
R3 [1, 0] to [1, 1].
Table 10 shows the input data format for programming this
register.
Noise and Spur Mode
Noise and spur mode allows the user to optimize a design either
for improved spurious performance or for improved phase noise
performance. When the lowest spur setting is chosen, dither is
enabled. This randomizes the fractional quantization noise so
that it looks more like white noise than spurious noise, meaning
that the part is optimized for improved spurious performance.
This operation is typically used when the PLL closed-loop band-
width is wide for fast-locking applications. A wide-loop bandwidth
is defined as a loop bandwidth greater than 1/10 of the RF
channel step resolution (f
the spurs to a level that a narrow-loop bandwidth would. When
the low noise and spur setting is enabled, dither is disabled.
This optimizes the synthesizer to operate with improved noise
performance. However, the spurious performance is degraded
in this mode compared with the lowest spur setting. To further
improve noise performance, the lowest noise setting option can
be used, which reduces the phase noise. As well as disabling the
dither, it ensures that the charge pump operates in an optimum
region for noise performance. This setting is extremely useful if
a narrow-loop filter bandwidth is used. The synthesizer ensures
extremely low noise, and the filter attenuates the spurs. The
typical performance characteristics show the trade-offs in a
typical WCDMA setup for different noise and spur settings.
RESERVED BITS
These bits should be set to 0 for normal operation.
RES
). A wide-loop filter does not attenuate
IN
frequency when the doubler is
ADF4154
OUT