- Output short-circuit protection
- Thermal overload protection
- Stereo filterless Class D operation
- Spread spectrum modulation
- Ground-referenced headphone driver
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I 2 C control interface
- 32-step input volume control
- Output volume control
- Minimal external components
- Click inhibition
- Micropower shutdown
- A space-saving 36-ball μSMD package is available
- Single-supply operation
- RF rejection
illustrate
The LM49250 is a fully integrated audio subsystem designed for stereo mobile applications. The LM49250 combines 45mW/Ch stereo ground with a 2.4W/Ch stereo Class D speaker amplifier, headphone amplifier, Class AB headphone amplifier, national 3D boost, volume control, input mixer reference into a single device. The filterless Class D amplifier can be loaded into 8Ω
The LM49250 features a new circuit technique that uses a charge pump to generate a negative supply voltage. This skews the headphone output to ground, eliminating the need for output coupling capacitors.
To improve interference immunity, the LM49250 features fully differential left, right, and mono inputs. Three inputs, you can mix/multiply the output of any speaker, headphone or earpiece amplifier. Left and right differential inputs that can be used as independent single-ended inputs, mixing multiple stereo audio sources. Mixer, volume control and device mode selection control, via I 2 C-compatible interface.
Output short-circuit and thermal overload protection prevents damage to the device under fault conditions. Advanced click suppression eliminates power-up/down and audible transient noise when off.
Main specifications
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■ Power output in VDD= 5V
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Speaker: RL =4Ω，THD + N ≤ 1％ RL =4Ω，THD + N ≤ 10％ RL =8Ω，THD + N ≤ 1％
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1.97W/Ch 2.4W/Ch 1.2W/Ch
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Earphone: RL =16Ω，THD + N ≤ 1％ RL =32Ω，THD + N ≤ 1％
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41mW/Ch 45mW/Ch
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Receiver: RL =16Ω，THD + N ≤ 1％ RL =32Ω，THD + N ≤ 1％
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170mW 90MW
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■ Shutdown current
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0.1μA
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■ At 5V, the efficiency is 8Ω1W
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87％
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■ At 3.6V, 500mW has an efficiency of 8Ω
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85％
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apply
- mobile phone
- Portable navigation devices
- Portable media player
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