AD9508/PCBZ Analog Devices, AD9508/PCBZ Datasheet - Page 24

• Manufacturer Part Number: AD9508/PCBZ
• Description: Clock & Timer Development Tools 1
• Manufacturer: Analog Devices
• Type: Clock Buffersr

Specifications of AD9508/PCBZ

• Rohs: yes
• Product: Evaluation Boards
• Tool Is For Evaluation Of: AD9508
• Frequency: 250 MHz, 1.65 GHz
• Operating Supply Voltage: 6 V
• Description/function: High performance 1
• Interface Type: I2C, SPI, USB
• Factory Pack Quantity: 1

OUTPUT CLOCK SYNCHRONIZATION
On power up, the default output channel divider value is divide-
by-1 if SPI and I
there is no real requirement for synchronization after power up
unless a change in divider value or a phase offset value is
desired. A hard asynchronous output synchronization is
executed by briefly pulling the SYNC pin low. This forces the
outputs to be edge aligned regardless of their divide ratio after
the SYNC pin is released.
If the sync mask bit is set to a Logic 1 in any output channel,
those channels continue working uninterrupted while a sync
operation is being applied to other channels. Outputs are pulled
low while SYNC is low if they are not masked by the sync mask
bit. This only applies if outputs are functioning under normal
operation with its logic level set to 11 or toggle mode.
POWER SUPPLY
The
down to a 2.5 V − 5% power supply. Best practice recommends
bypassing the power supply on the printed circuit board (PCB)
with adequate capacitance (>10 µF) and bypassing all power pins
with adequate capacitance (0.1 µF) as close to the part as possible.
The layout of the
available at www.analog.com, provides a good layout example
for this device.
AD9508
AD9508
is designed to work off a 3.3 V + 5% power supply
2
AD9508
C programming modes are used. Therefore,
evaluation board (AD9508/PCBZ),
Rev. A | Page 24 of 40
THERMALLY ENHANCED PACKAGE MOUNTING
GUIDELINES
Exposed Metal Paddle
The exposed metal paddle on the
electrical connection, as well as a thermal enhancement. For the
device to function properly, the paddle must be properly
attached to ground (VSS). The
its exposed paddle. The PCB acts as a heat sink for the AD9508.
The PCB attachment must provide a good thermal path to a
larger heat dissipation area, such as the ground plane on the
PCB. This requires a grid of vias from the top layer down to the
ground plane. See Figure 47 for an example.
Refer to the
Manufacturing Guide for the Lead Frame Chip Scale Package
(LFCSP), for more information about mounting devices with
an exposed paddle.
Figure 47. PCB Land Example for Attaching Exposed Paddle
AN-772 Application
VIAS TO GND PLANE
AD9508
Note, A Design and
AD9508
dissipates heat through
package is an
Data Sheet