LM49450SQ/NOPB National Semiconductor, LM49450SQ/NOPB Datasheet - Page 35

• Manufacturer Part Number: LM49450SQ/NOPB
• Description: IC AUDIO SUBSYSTEM 2.5W D 32LLP
• Manufacturer: National Semiconductor
• Series: Boomer®r
• Type: Class Dr

Specifications of LM49450SQ/NOPB

• Output Type: 2-Channel (Stereo) with Stereo Headphones
• Max Output Power X Channels @ Load: 2.5W x 2 @ 4 Ohm
• Voltage - Supply: 2.7 V ~ 5.5 V
• Features: 3D, DAC, Depop, I²C, I²S, Mute, Short-Circuit and Thermal Protection, Shutdown, Volume Control
• Mounting Type: Surface Mount
• Package / Case: 32-LLP
• Amplifier Class: D
• No. Of Channels: 2
• Output Power: 1.2W
• Supply Voltage Range: 2.7V To 5.5V
• Load Impedance: 8ohm
• Operating Temperature Range: -40°C To +85°C
• Amplifier Case Style: LLP
• Rohs Compliant: Yes
• For Use With: LM49450SQEVAL - BOARD EVAL FOR LM49450
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: LM49450SQ; LM49450SQ; LM49450SQTR

PCB Layout Guidelines
Minimize trace impedance of the power, ground and all output
traces for optimum performance. Voltage loss due to trace
resistance between the LM49450 and the load results in de-
creased output power and efficiency. Trace resistance be-
tween the power supply and ground has the same effect as a
poorly regulated supply, increased ripple and reduced peak
output power. Use wide traces for power supply inputs and
amplifier outputs to minimize losses due to trace resistance,
as well as route heat away from the device. Proper grounding
improves audio performance, minimizes crosstalk between
channels and prevents switching noise from interfering with
the audio signal. Use of power and ground planes is recom-
mended.
Place all digital components and route digital signal traces as
far as possible from analog components and traces. Do not
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run digital and analog traces in parallel on the same PCB lay-
er. If digital and analog signal lines must cross either over or
under each other, ensure that they cross in a perpendicular
fashion.
Exposed DAP Mounting
Considerations
The LM49450 LLP package features an exposed die-attach
(thermal) pad on its backside. The exposed pad provides a
direct heat conduction path from the die to the PCB, reducing
the thermal resistance of the package. Connect the exposed
pad to GND with a large pad and via to a large GND plane on
the bottom of the PCB for best heat distribution.
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