DC1437B-AA Linear Technology, DC1437B-AA Datasheet - Page 21

• Manufacturer Part Number: DC1437B-AA
• Description: BOARD EVAL LTM9003-AA
• Manufacturer: Linear Technology
• Type: Pre-Distortion Receiver Subsystemr

Specifications of DC1437B-AA

• Design Resources: DC1437 Schematic
• Frequency: 184MHz
• Features: LTM9003 12bit Predistortion Receiver Subsystem
• Tool / Board Applications: Wireless Connectivity-ZigBee, RF, Infrared, USB
• Mcu Supported Families: LTM9003
• Development Tool Type: Hardware - Eval/Demo Board
• For Use With/related Products: LTM9003
• Lead Free Status / RoHS Status: Not applicable / Not applicable

applicaTions inForMaTion
Grounding and Bypassing
The LTM9003 requires a printed circuit board with a
clean unbroken ground plane; a multilayer board with an
internal ground plane is recommended. The pinout of the
LTM9003 has been optimized for a flow-through layout
so that the interaction between inputs and digital outputs
is minimized. Ample ground pads facilitate a layout that
ensures that digital and analog signal lines are separated
as much as possible.
The LTM9003 is internally bypassed with the ADC (V
amplifier (V
common ground (GND). The digital output supply (OV
is returned to OGND. Additional bypass capacitance is
optional and may be required if power supply noise is
significant.
Heat Transfer
Most of the heat generated by the LTM9003 is transferred
through the bottom-side ground pads. For good electrical
and thermal performance, it is critical that all ground pins
are connected to a ground plane of sufficient area with as
many vias as possible.
Recommended Layout
The high integration of the LTM9003 makes the PCB board
layout very simple and easy. However, to optimize its electri-
cal and thermal performance, some layout considerations
are still necessary.
CC2
) and mixer (V
CC1
) supplies returning to a
DD
DD
),
)
• Use large PCB copper areas for ground. This helps to
dissipate heat in the package through the board and also
helps to shield sensitive on-board analog signals. Common
ground (GND) and output ground (OGND) are electrically
isolated on the LTM9003, but can be connected on the PCB
underneath the part to provide a common return path.
• Use multiple ground vias. Using as many vias as pos-
sible helps to improve the thermal performance of the
board and creates necessary barriers separating analog
and digital traces on the board at high frequencies.
• Separate analog and digital traces as much as possible,
using vias to create high-frequency barriers. This will re-
duce digital feedback that can reduce the signal-to-noise
ratio (SNR) and dynamic range of the LTM9003.
Figures 12 through 15 give a good example of the recom-
mended layout.
The quality of the paste print is an important factor in
producing high yield assemblies. It is recommended to
use a type 3 or 4 printing no-clean solder paste. The solder
stencil design should follow the guidelines outlined in
Application Note 100.
The LTM9003 employs gold-finished pads for use with
Pb-based or tin-based solder paste. It is inherently Pb-free
and complies with the JEDEC (e4) standard. The materi-
als declaration is available online at http://www.linear.
com/leadfree/mat_dec.jsp.
LTM9003

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