1FEATURES
2• 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

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).