NS 公司的LM49153是全集成音频子系统，包括高效25mW的G类耳机放大器（THD+N ≤ 1%）和高效的1.35W D类扬声器放大器（RL = 8Ω, THD+N < 1%），通过I2C进行音量，模式选择和关断控制，主要用在手机和智能手机。本文介绍了LM49153主要指标，主要特性，典型音频放大器应用电路以及演示板电路图和材料清单，元件布局图。
The LM49153 is a fully integrated audio subsystem designed for portable handheld applications such as cellular phones.
Part of National’s PowerWise family of products, the LM49153 combines an earpiece switch, a high efficiency 25mW class G headphone amplifier, and a high efficiency 1.35W class D loudspeaker into a single device.
The headphone amplifiers feature National’s class G ground referenced architecture that creates a ground-referenced output with dynamic supply rails for optimum efficiency. The
class D amplifier features an ALC (Automatic Level Control) with a noise gate that provides both no-clip and speaker protection.
Mode selection, shutdown control, and volume are controlled through an I2C compatible interface. Click and pop suppression eliminates audible transients on power-up/down and during shutdown. The LM49153 is available in an ultra-small 25-bump 0.4mm pitch micro SMD package (2.30mm x 2.42mm).

LM49153主要指标：
■ Class G Headphone Amplifier,
HPVDD = 1.8V, RL = 32Ω
IDDQHP 1.2mA (typ)
POUT, THD+N ≤ 1% 25mW (typ)
HP VOS 0.5mV (typ)
■ Mono Class D Speaker Amplifier
RL = 8Ω, THD+N < 1%
POUT, LSVDD = 5.0V 1.35W (typ)
POUT, LSVDD = 3.6V 680mW (typ)
Efficiency 88% (typ)

LM49153主要特性：
■ Class G Ground Referenced Headphone Outputs
■ High Efficiency Class D Amplifier with Spread Spectrum
■ No Clip
■ Speaker Protection
■ Noise Gate
■ I2C Volume and Mode Control
■ Advanced Click-and-Pop Suppression
■ Micro-power shutdown
LM49153应用：
■ Feature phones
■ Smart phones

图1。LM49153典型音频放大器应用电路

图2。LM49153演示板电路图
LM49153演示板材料清单：


图3。LM49153演示板元件布局图（顶层）

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