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LM49250 -
Enhanced Emissions Suppression Stereo Class D Audio Sub-System with Ground Referenced Headphone Amplifier from the PowerWise® Family
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Features
| • | Output Short Circuit Protection |
| • | Thermal Overload Protection |
| • | Stereo filterless Class D operation |
| • | Spread spectrum modulation |
| • | Ground referenced Headphone Drivers |
| • | I
2C Control Interface
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| • | 32-step input volume control |
| • | Output volume control |
| • | Minimum external components |
| • | Click and Pop suppression |
| • | Micro-power shutdown |
| • | Available in space-saving 36–bump µSMD package |
| • | Single supply operation |
| • | RF suppression |
Key Specification
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Power Output at 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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| Headphone:
RL = 16Ω, THD+N
≤ 1%
RL = 32Ω, THD+N
≤ 1%
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41mW/Ch
45mW/Ch
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| Earpiece:
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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Efficiency at 5V, 1W into 8Ω
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87%
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Efficiency at 3.6V, 500mW into 8Ω
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85%
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General Description
The LM49250 is a fully integrated audio subsystem designed for stereo cell phone applications. More...
Applications
| • | Mobile phones |
| • | Portable Navigation Devices |
| • | Portable Media Players |
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Typical Application
click for larger image
| Parameters | Values |
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| Power@ 4Ohms, 10% THD |
1.210 Watt |
| Power@ 4Ohms, 1% THD |
0.985 Watt |
| Power@ 8Ohms, 10% THD |
0.775 Watt |
| Power@ 8Ohms, 1% THD |
0.625 Watt |
| THD |
0.02 % |
| PSRR |
95 dB |
| SNR |
Undefined dB |
| Channels |
3 Channels |
| THD Conditions |
LS mode 2, RL=8ohms, Pout=300mW |
| PSRR Conditions |
HP mode 2, f=217Hz, Vripple=200mVpp |
| SNR Conditions |
Undefined |
| User Supply |
3.6 Volt |
| Audio Mux |
Yes |
| Capless Headphone |
Yes |
| ClassD Driver |
Yes |
| Interface |
I2C |
| Stereo Inputs |
2 |
| National 3D |
Yes |
| Digital Volume Control Max |
21 dB |
| Digital Volume Control Min |
-64 dB |
| Output Modes |
100 |
| Supply Range |
+2.7 - +5.5 V |
| Mono Inputs |
Differential |
| Temperature Min |
-40 deg C |
| Temperature Max |
85 deg C |
| Loudspeaker Type |
Class D |
| Headphone Type |
True Ground |
| Loudspeaker Outputs |
3 |
| PowerWise |
Yes |
Typical Performance
click for larger image
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Connection Diagram
click for larger image
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Datasheet
RoHS Compliance Information
| Size in Kbytes | Date |
 |
| LM49250 Enhanced Emissions Suppression Stereo Class D Audio Sub-System with Ground Referenced Headphone Amplifier and Mono Earpiece |
1350
Kbytes |
15-Dec-08 |
Download |
Package Availability, Models, Samples & Pricing
General Description
The LM49250 is a fully integrated audio subsystem designed for stereo cell phone applications. The LM49250 combines a 2.4W/Ch
stereo class D speaker amplifiers with a 45mW/Ch stereo ground referenced headphone amplifier, a class AB earpiece amplifier,
National 3D enhancement, volume control, and an input mixer into a single device. The filterless class D amplifiers deliver
1.2W/Ch into an 8Ω load with <1% THD+N from a 5V supply.
The LM49250 features a new circuit technology that utilizes a charge pump to generate a negative supply voltage. This allows
the headphone outputs to be biased about ground, thereby eliminating the output-coupling capacitors.
For improved noise immunity, the LM49250 features fully differential left, right and mono inputs. The three inputs can be
mixed/multiplexed to any output combination of the loudspeaker, headphone or earpiece amplifiers. The left and right differential
inputs can be used as separate single-ended inputs, mixing multiple stereo audio sources. The mixer, volume control, and
device mode select are controlled through an I
2C compatible interface.
Output short circuit and thermal overload protection prevent the device from being damaged during fault conditions. Superior
click and pop suppression eliminates audible transients on power-up/down and during shutdown.
[Information as of 7-Nov-2009]
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