Document
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: – VDD = 3.3V, 450mW/Ch into 8Ω 84% – VDD = 5V, 1W/Ch into 8Ω 84%
• Quiescent Power Supply Current, VDD = 3.3V – Speaker Mode 5.5 mA – Headphone Mode (OCL) 4 mA
• Power Output/Channel, VDD = 5V – Class D Speaker Amplifier: – RL = 4Ω, THD+N = ≤ 10% 2.3 W – RL = 8Ω, THD+N = ≤ 1% 106 W
– Headphone Amplifier:
– RL = 16Ω, THD+N = ≤ 1% 155 mW
– RL = 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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Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. All trademarks are the property of their respective owners.
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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
LM49270
SNAS384B – DECEMBER 2006 – REVISED MARCH 2007
www.ti.com
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates.
Typical Application
VDD
CS
CS
VDD LSVDD
LSVDD
Audio Input CIN
LIN
L3DIN R3D
R3DADJ
C3D
Audio Input
R3DIN
CIN
RIN
3D CONTROL
SPEAKER VOLUME CONTROL
LLS+ LLSLSGND
RLS+ RLS-
HPS
BYPASS CB I2CVDD
Bias Click/Pop Suppresion
I2CVDD
SDA
I2C
BUS
SCL
I2C Interface
ADR
HEADPHONE VOLUME CONTROL
GND
LHP RHP
VOC
HPVDD
HPVDD
VIH
CS
VIL
Figure 1. Typical Audio Amplifier Application Circuit
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Product Folder Links: LM49270
Copyright © 2006–2007, Texas Instruments Incorporated
www.ti.com
Connection Diagram
LM49270
SNAS384B – DECEMBER 2006 – REVISED MARCH 2007
GND HPS SCL SDA LSVDD LLS+ LLS28 27 26 25 24 23 22
RHP 1
21 NC
VOC 2
20 ADR
LHP 3 HPVDD 4
19 VDD 18 LSGND
R3DIN 5 L3DIN 6 BYPASS 7
17 I2CVDD 16 NC 15 NC
8 9 10 11 12 13 14
LIN RIN GND NC LSVDD RLS+ RLS-
Figure 2. WQFN Package 5mm x 5mm x 0.8mm Top View
See Package Number RSG0028A
Pin Descriptions
PIN
NAME
1
RHP
2
VOC
3
LHP
4
HPVDD
5
R3DIN
6
L3DIN
7
BYPASS
8
LIN
9
RIN
10
GND
11
NC
12
LSVDD
13
RLS+
14
RLS-
15
NC
16
NC
17
I2CVDD
18
LSGND
19
VDD
20
ADR
21
NC
22
LLS-
.