LM49270 Datasheet, PDF (1/28 Pages) Texas Instruments – Filterless 2.2W Stereo Class D Audio Subsystem with OCL Headphone Amplifier, 3D Enhancement, and Headphone Sense

LM49270
www.ti.com
SNAS384B – DECEMBER 2006 – REVISED MARCH 2007
LM49270
Filterless 2.2W Stereo Class D Audio
Subsystem with OCL Headphone Amplifier, 3D Enhancement, and Headphone Sense
Check for Samples: LM49270
FEATURES
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•2 Stereo Filterless Class D Amplifier
• Selectable OCL/CC Headphone Amplifier
• Headphone Sense Ability
• TI’s 3D Enhancement
• RF Suppression
• I²C Control Interface
• 32-Step Digital Volume Control
• 6 Operating Modes
• Output Short Circuit Protection and Thermal
Shutdown Protection
• Minimum External Components
• Click and Pop Suppression
• Micro-Power Shutdown
• Independent Speaker and Headphone Volume
Controls
• Available in Space-Saving 28 Pin WQFN
Package
APPLICATIONS
• Portable DVD Players
• Smart Phones
• PDAs
• Laptops
KEY SPECIFICATIONS
• Stereo Class D Amplifier Efficiency:
– V_DD = 3.3V, 450mW/Ch into 8Ω 84%
– V_DD = 5V, 1W/Ch into 8Ω 84%
• Quiescent Power Supply Current, V_DD = 3.3V
– Speaker Mode 5.5 mA
– Headphone Mode (OCL) 4 mA
• Power Output/Channel, V_DD = 5V
– Class D Speaker Amplifier:
– R_L = 4Ω, THD+N = ≤ 10% 2.3 W
– R_L = 8Ω, THD+N = ≤ 1% 106 W
– Headphone Amplifier:
– R_L = 16Ω, THD+N = ≤ 1% 155 mW
– R_L = 32Ω, THD+N = ≤ 1% 90 mW
• Shutdown Current 0.02μA
DESCRIPTION
The LM49270 is a fully integrated audio subsystem
designed for stereo multimedia applications. The
LM49270 combines a 2.2W stereo Class D amplifier
with a 155mW stereo headphone amplifier, volume
control, headphone sense, and TI’s unique 3D sound
enhancement into a single device. The LM49270
uses flexible I²C control interface for multiple
application requirements.
The filterless stereo class D amplifiers delivers
2.2W/channel into a 4Ω load with less than 10%
THD+N with a 5V supply. The headphone amplifier
features Output Capacitor-less (OCL) architecture
that eliminates the output coupling capacitors
required by traditional headphone amplifiers.
The IC features a headphone sense input (HPS) that
automatically detects the presence of a headphone
and configures the device accordingly. The LM49270
can automatically switch from OCL headphone output
to a line driver output. If the VOC pin is pulled to
GND, the VOC amplifier is disabled and the VOC pin
is internally set to GND. This feature allows the
LM49270 to be used as a line driver in OCL mode
without a GND conflict on the headphone jack sleeve.
Additionally, the headphone amplifier can be
configured as capacitively coupled (CC).
The LM49270 features a 32 step volume control for
the headphone and stereo outputs. The device mode
select and volume are controlled through an I²C
compatible interface.
Output short circuit and thermal shutdown protection
prevent the device from being damaged during fault
conditions. Superior click and pop suppression
eliminates audible transients on power-up/down and
during shutdown. The LM49270 is available in a
space saving 28-pin, 5x5mm WQFN package.
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Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
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2
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2006–2007, Texas Instruments Incorporated