Features
| • | Class G Power Savings |
| • | Ground Referenced Headphone Outputs – Eliminates Output Coupling Capacitors |
| • | Common-Mode Sense |
| • | I
2C Volume and Mode Control
|
| • | High Output Impedance in Shutdown |
| • | Differential Inputs |
| • | Advanced Click-and-Pop Suppression |
| • | Low Supply Current |
| • | Low THD mode option |
Description The LM48824 is a Class G, ground-referenced stereo headphone amplifier designed for portable devices. The LM48824 features
National’s ground-referenced architecture, which eliminates the large DC blocking capacitors required by traditional headphone
amplifiers, saving board space and minimizing system cost.
The LM48824 takes advantage of National’s patent-pending Class G architecture offering power savings compared to a traditional
Class AB headphone amplifier. Additionally, output noise is improved by common-mode sensing that corrects for any differences
between the amplifier ground and the potential at the headphone return terminal, minimizing noise created by any ground mismatches.
A high output impedance mode allows the LM48824's outputs to be driven by an external source without degrading the signal.
Other features include flexible power supply requirements, differential inputs for improved noise rejection, a low power
(2.5μA) shutdown mode, and a 32-step I
2C volume control with mute function.
The LM48824's superior click and pop suppression eliminates audible transients on power-up/down and during shutdown. The LM48824
is available in an ultra-small 16-bump, 0.4mm pitch micro SMD package (1.69mm x 1.69mm)
Key Specification
| ■ Quiescent Power Supply Current at 3.6V
|
0.9mA (typ)
|
| ■ Output Power/channel at VDD = 3.6V
RL = 16Ω, THD+N
≤ 1%
|
37mW (typ)
|
| ■ Output Power/channel at VDD = 3.6V
RL = 32Ω, THD+N
≤ 1%
|
29mW (typ)
|
| ■ PSRR at 217Hz
|
100dB (typ)
|
| ■ Shutdown current
|
2.5μA (typ)
|
Applications
| • | Mobile Phones, PDAs, MP3 Players |
| • | Portable Electronic Devices, Notebook PCs |
|
|
