AD9552BCPZ-REEL7 Analog Devices Inc, AD9552BCPZ-REEL7 Datasheet - Page 16

• Manufacturer Part Number: AD9552BCPZ-REEL7
• Description: Precision Clock Translator
• Manufacturer: Analog Devices Inc
• Type: Clock Generatorr

Specifications of AD9552BCPZ-REEL7

• Design Resources: Clock Distribution Circuit with Pin-Programmable Output Frequency, Output Logic Levels, and Fanout (CN0152)
• Pll: Yes
• Input: Clock, Crystal
• Output: CMOS, LVDS, LVPECL
• Number Of Circuits: 1
• Ratio - Input:output: 2:2
• Differential - Input:output: No/Yes
• Frequency - Max: 900MHz
• Divider/multiplier: Yes/No
• Voltage - Supply: 3.3V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 32-LFCSP
• Frequency-max: 900MHz
• Number Of Elements: 1
• Pll Input Freq (min): 6.6MHz
• Pll Input Freq (max): 112.5MHz
• Operating Supply Voltage (typ): 3.3V
• Operating Temp Range: -40C to 85C
• Package Type: LFCSP EP
• Output Frequency Range: 0 to 900MHz
• Operating Temperature Classification: Industrial
• Pin Count: 32
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

AD9552
The gain of the PLL is proportional to the current delivered
by the charge pump. The user can override the default charge
pump current setting, and, thereby, the PLL gain, by using
Register 0x0A[7:0].
The PLL has a VCO with 128 frequency bands spanning a range
of 3350 MHz to 4050 MHz (3700 MHz nominal). However, the
actual operating frequency within a particular band depends on
the control voltage that appears on the loop filter capacitor. The
control voltage causes the VCO output frequency to vary linearly
within the selected band. This frequency variability allows the
control loop of the PLL to synchronize the VCO output signal
with the reference signal applied to the PFD. Typically, selection
of the VCO frequency band (as well as gain adjustment) occurs
automatically as part of the device’s automatic VCO calibration
process, which initiates at power up (or reset). Alternatively, the
user can force VCO calibration by first enabling SPI control of
VCO calibration (Register 0x0E[2] = 1) and then writing a 1 to
the calibrate VCO bit (Register 0x0E[7]). To facilitate system
debugging, the user can override the VCO band setting by first
enabling SPI control of VCO band (Register 0x0E[0] = 1) and
then writing the desired value to Register 0x10[7:1].
The PLL has a feedback divider coupled with a third-order
SDM that enables the PLL to provide integer-plus-fractional
frequency upconversion. The integer factor, N, is variable via
an 8-bit programming register. The range of N is from N
255, where N
disabled or enabled, respectively. The SDM in the feedback path
allows for a fractional divide value that takes the form of N +
F/M, where N is the integer part (eight bits), M is the modulus
(20 bits), and F is the fractional part (20 bits), with all three
parameters being positive integers.
The feedback SDM gives the AD9552 the ability to support a
wide range of output frequencies with exact frequency ratios
relative to the input reference.
PLL Locked Indicator
The PLL provides a status indicator that appears at an external
pin (LOCKED). The indicator shows when the PLL has acquired
a locked condition.
Output Dividers
Two integer dividers exist in the output chain. The first divider (P
yields an integer submultiple of the VCO frequency. The second
divider (P
submultiple of the output frequency of the P
Input-to-OUT2 Option
By default, OUT2 delivers an output frequency that is the same
frequency as OUT1. However, the user has the option of making
OUT2 a replica of the input frequency (REF or XTAL) by
programming Register 33[3] = 1.
1
) establishes the frequency at OUT1 as an integer
MIN
is 36 or 47 depending on whether the SDM is
0
divider.
MIN
to
Rev. C | Page 16 of 32
0
)
Output Drivers
The user has control over the following output driver parameters
via the programming registers:
•
•
•
•
The logic families are LVDS, LVPECL, and CMOS. Selection of
the logic family is via the mode control bits in the OUT1 driver
control register (Register 0x32[5:3]) and the OUT2 driver control
register (Register 0x34[5:3]), as detailed in Table 11. Regardless
of the selected logic family, each output driver uses two pins:
OUT1 and OUT1 are used by one driver, and OUT2 and OUT2
are used by the other. This enables support of the differential
signals associated with the LVDS and LVPECL logic families.
CMOS, on the other hand, is a single-ended signal requiring
only one output pin, but both output pins are available for
optional provision of a dual, single-ended CMOS output clock.
Refer to the first entry (CMOS (both pins)) in
Table 11. Output Channel Logic Family and Pin Functionality
Mode
Control Bits[2:0]
000
001
010
011
100
101
110
111
If the mode bits indicate the CMOS logic family, the user has
control of the logic polarity associated with each CMOS output
pin via the OUT1 and OUT2 driver control registers.
If the mode bits indicate the CMOS or LVDS logic family, the
user can select whether the output driver uses weak or strong
drive capability via the OUT1 and OUT2 driver control registers.
In the case of the CMOS family, the strong setting allows for
driving increased capacitive loads. In the case of the LVDS
family, the nominal weak and strong drive currents are 3.5 mA
and 7 mA, respectively.
The OUT1 and OUT2 driver control registers also have a power-
down bit to enable/disable the output drivers. The power-down
function is independent of the logic family selection.
Note that, unless the user programs the device to allow SPI port
control of the output drivers, the drivers default to LVPECL or
LVDS, depending on the logic level on the OUTSEL pin (Pin 15).
For OUTSEL = 0, both outputs are LVDS. For OUTSEL = 1, both
outputs are LVPECL. In the pin-selected LVDS mode, the user
can still control the drive strength, using the SPI port.
Logic family and pin functionality
Polarity (for CMOS family only)
Drive current
Power-down
Logic Family and Pin Functionality
CMOS (both pins)
CMOS (positive pin), tristate (negative pin)
Tristate (positive pin), CMOS (negative pin)
Tristate (both pins)
LVDS
LVPECL
Undefined
Undefined
Table 11
.