AD9520-3BCPZ Analog Devices Inc, AD9520-3BCPZ Datasheet - Page 54

• Manufacturer Part Number: AD9520-3BCPZ
• Description: 12/24 Channel Clock Gen 2,0GH
• Manufacturer: Analog Devices Inc
• Type: Clock Generator, Fanout Distributionr

Specifications of AD9520-3BCPZ

• Design Resources: Synchronizing Multiple AD9910 1 GSPS Direct Digital Synthesizers (CN0121) Phase Coherent FSK Modulator (CN0186)
• Pll: Yes
• Input: CMOS, LVDS, LVPECL
• Output: CMOS, LVPECL
• Number Of Circuits: 1
• Ratio - Input:output: 2:12, 2:24
• Differential - Input:output: Yes/Yes
• Frequency - Max: 2.25GHz
• Divider/multiplier: Yes/No
• Voltage - Supply: 3.135 V ~ 3.465 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 64-LFCSP
• Frequency-max: 2.25GHz
• Function: Clock Generator
• Operating Temperature (max): 85C
• Operating Temperature (min): -40C
• Package Type: LFCSP EP
• Pin Count: 64
• Mounting: Surface Mount
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

AD9520-3
SPI SERIAL PORT OPERATION
Pin Descriptions
SCLK (serial clock) is the serial shift clock. This pin is an input.
SCLK is used to synchronize serial control port reads and writes.
Write data bits are registered on the rising edge of this clock,
and read data bits are registered on the falling edge. This pin is
internally pulled down by a 30 kΩ resistor to ground.
SDIO (serial data input/output) is a dual-purpose pin and acts
either as an input only (unidirectional mode) or as both an
input/output (bidirectional mode). The AD9520 defaults to the
bidirectional I/O mode (0x000[7] = 0).
SDO (serial data out) is used only in the unidirectional I/O
mode (0x000[7]) as a separate output pin for reading back data.
CS (chip select bar) is an active low control that gates the read
and write cycles. When CS is high, SDO and SDIO are in a high
impedance state. This pin is internally pulled up by a 30 kΩ
resistor to VS.
SPI Mode Operation
In SPI mode, single or multiple byte transfers are supported, as
well as MSB first or LSB first transfer formats. The AD9520
serial control port can be configured for a single bidirectional
I/O pin (SDIO only) or for two unidirectional I/O pins (SDIO/
SDO). By default, the AD9520 is in bidirectional mode. Short
instruction mode (8-bit instructions) is not supported. Only
long (16-bit) instruction mode is supported.
A write or a read operation to the AD9520 is initiated by pulling
CS low.
The CS stalled high mode is supported in data transfers where
three or fewer bytes of data (plus instruction data) are transferred
(see
high on any byte boundary, allowing time for the system controller
to process the next byte. CS can go high on byte boundaries only
and can go high during either part (instruction or data) of the
transfer.
During this period, the serial control port state machine enters
a wait state until all data is sent. If the system controller decides
to abort the transfer before all of the data is sent, the state machine
must be reset by either completing the remaining transfers or by
returning CS low for at least one complete SCLK cycle (but less
than eight SCLK cycles). Raising the CS pin on a nonbyte
boundary terminates the serial transfer and flushes the buffer.
Table 43
). In this mode, the
SCLK/SCL
SDIO/SDA
Figure 61. Serial Control Port
SDO
CS
15
16
17
18
CS pin can temporarily return
AD9520
CONTROL
SERIAL
PORT
Rev. 0 | Page 54 of 84
In the streaming mode (see Table 43), any number of data bytes
can be transferred in a continuous stream. The register address
is automatically incremented or decremented (see the SPI
MSB/LSB First Transfers section). CS must be raised at the end
of the last byte to be transferred, thereby ending streaming mode.
Communication Cycle—Instruction Plus Data
There are two parts to a communication cycle with the AD9520.
The first part writes a 16-bit instruction word into the AD9520,
coincident with the first 16 SCLK rising edges. The instruction
word provides the AD9520 serial control port with information
regarding the data transfer, which is the second part of the
communication cycle. The instruction word defines whether
the upcoming data transfer is a read or a write, the number of
bytes in the data transfer, and the starting register address for
the first byte of the data transfer.
Write
If the instruction word is for a write operation, the second part
is the transfer of data into the serial control port buffer of the
AD9520. Data bits are registered on the rising edge of SCLK.
The length of the transfer (one, two, or three bytes, or streaming
mode) is indicated by two bits (W1:W0) in the instruction byte.
When the transfer is one, two, or three bytes, but not streaming,
CS can be raised after each sequence of eight bits to stall the bus
(except after the last byte, where it ends the cycle). When the bus
is stalled, the serial transfer resumes when CS is lowered. Raising
the CS pin on a nonbyte boundary resets the serial control port.
During a write, streaming mode does not skip over reserved or
blank registers; therefore, the user must know what bit pattern
to write to the reserved registers to preserve proper operation of
the part. It does not matter what data is written to blank registers.
Because data is written into a serial control port buffer area, not
directly into the actual control registers of the AD9520, an
additional operation is needed to transfer the serial control port
buffer contents to the actual control registers of the AD9520,
thereby causing them to become active. The update registers
operation consists of setting 0x232[0] = 1b (this bit is self-
clearing). Any number of bytes of data can be changed before
executing an update registers. The update registers simultaneously
actuates all register changes that have been written to the buffer
since any previous update.
Read
The AD9520 supports only the long instruction mode. If the
instruction word is for a read operation, the next N × 8 SCLK
cycles clock out the data from the address specified in the
instruction word, where N is 1 to 3 as determined by W1:W0.
If N = 4, the read operation is in streaming mode, continuing
until CS is raised. Streaming mode does not skip over reserved
or blank registers. The readback data is valid on the falling
edge of SCLK.