LM4947_14 Datasheet, PDF (1/37 Pages) Texas Instruments – Mono Class D and Stereo Audio Sub-System with OCL Headphone Amplifier and National 3D

LM4947, LM4947TLEVAL
www.ti.com
SNAS349C – JUNE 2006 – REVISED NOVEMBER 2007
LM4947
Mono Class D and Stereo Audio Sub-System
with OCL Headphone Amplifier and National 3D
Check for Samples: LM4947, LM4947TLEVAL
FEATURES
1
•2 I²C Control Interface
• I²C programmable National 3D Audio
• I²C controlled 32 step digital volume control (-
59.5dB to +18dB)
• Three independent volume channels (Left,
Right, Mono)
• Eight distinct output modes
• Small, 25–bump micro SMD packaging
• “Click and Pop” suppression circuitry
• Thermal shutdown protection
• Low shutdown current (0.1μA, typ)
• RF suppression
• Differential mono and stereo inputs
• Stereo input mux
APPLICATIONS
• Mobile Phones
• PDAs
DESCRIPTION
The LM4947 is an audio subsystem capable of efficiently delivering 500mW (Class D operation) of continuous
average power into a mono 8Ω bridged-tied load (BTL) with 1% THD+N, 37mW (Class AB operation) power
channel of continuous average power into stereo 32Ω single-ended (SE) loads with 1% THD+N, or an output
capacitor-less (OCL) configuration with identical specification as the SE configuration, from a 3.3V power supply.
The LM4947 has six input channels: one pair for a two-channel stereo signal, the second pair for a secondary
two-channel stereo input, and the third pair for a differential single-channel mono input. Additionally, the two sets
of stereo inputs may be configured as a single stereo differential input (differential left and differential right). The
LM4947 features a 32-step digital volume control and eight distinct output modes. The digital volume control, 3D
enhancement, and output modes are programmed through a two-wire I²C compatible interface that allows
flexibility in routing and mixing audio channels.
The RF suppression circuitry in the LM4947 makes it well-suited for GSM mobile phones and other portable
applications in which strong RF signals generated by an antenna (and long output traces) may couple audibly
into the amplifier.
The LM4947 is designed for cellular phones, PDAs, and other portable handheld applications. It delivers high
quality output power from a surface-mount package and requires only eight external components in the OCL
mode (two additional components in SE mode).
Table 1. Key Specifications
THD+N at 1kHz, 500mW into 8Ω BTL (3.3V)
THD+N at 1kHz, 37mW into 32Ω SE (3.3V)
Single Supply Operation (V_DD)
I²C Single Supply Operation
VALUE
1.0% (typ)
1.0% (typ)
2.7 to 5.5
2.2 to 5.5
UNIT
V
V
1
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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