LM4947 - Mono Class D and Stereo Audio Sub-System with OCL Headphone Amplifier and TI 3D

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).

Products containing the "LM4947" keyword are: LM49473MT , LM4947TL , LM4947TL/NOPB , LM4947TL/NOPB , LM4947TLEVAL , LM4947TLEVAL , LM4947TLX , LM4947TLX/NOPB , LM4947TLX/NOPB

• I²C Control Interface
• I²C Programmable Texas Instruments 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 DSBGA 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

Key Specifications

• THD+N at 1kHz, 500mW into 8Ω BTL (3.3V): 1.0% (typ)
• THD+N at 1kHz, 37mW into 32Ω SE (3.3V): 1.0% (typ)
• Single Supply Operation (V_DD): 2.7 to 5.5 V
• I²C Single Supply Operation: 2.2 to 5.5 V

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