Features • I 2C Control Interface • I 2C programmable National 3D Audio • I 2C 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 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 I 2C 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). Key Specification ■  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 (VDD) 2.7 to 5.5V ■   I 2C Single Supply Operation 2.2 to 5.5V Applications • Mobile Phones • PDAs

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Datasheet

Title		Size	Date	Other Language
	LM4947   Mono Class D and Stereo Audio Sub-System with OCL Headphone Amplifier and National 3D	917 Kbytes	9-Nov-07

Featured Application Notes

Title		Size	Date	Other Language
	AN-1496: Application Note 1496 Noise, TDMA Noise, and Suppression Techniques	85 Kbytes	28-Apr-08	中文

More Application Notes

Title		Size	Date	Other Language
	AN-1567: Application Note 1567 LM4949 Demonstration Board	3533 Kbytes	18-Jul-07	中文
	AN-1496: Application Note 1496 Noise, TDMA Noise, and Suppression Techniques	85 Kbytes	28-Apr-08	中文

Design Tools

Title	Size	Date
Audio Amplifier Digital Control Interface Evaluation Board Software

Reliability Metrics

Part Number	Process	EFR Reject	EFR Sample Size	PPM	LTA Rejects	LTA Device Hours	FITS	MTTF (Hours)
LM4947TL	CMOS7	0	18406	0	0	1089000	4	309006723
LM4947TLX	CMOS7	0	18406	0	0	1089000	4	309006723

Note: The Early Failure Rates (EFR) were calculated as point estimate PPM based on rejects and sample size for EFR. The Long Term Failure Rates were calculated at 60% confidence using the Arrhenius equation at 0.7eV activation energy and derating the assumed stress temperature of 150°C to an application temperature of 55°C.

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