Features
| • | Spread Spectrum Class D architecture reduces EMI |
| • | Mono Class D 8Ω amplifier, 490 mW at 3.3V |
| • | OCL or AC-coupled headphone operation |
| • | 33mW stereo headphone amplifier at 3.3V |
| • | 115 mW earpiece amplifier at 3.3V |
| • | 18-bit stereo DAC |
| • | 16-bit mono ADC |
| • | 8 kHz to 192 kHz stereo audio playback |
| • | 8 kHz to 48 kHz mono recording |
| • | Bidirectional I
2S compatible audio interface
|
| • | Bidirectional PCM compatible audio interface for Bluetooth transceivers |
| • | I
2S-PCM Bridge with sample rate conversion
|
| • | Sigma-Delta PLL for operation from any clock at any sample rate |
| • | Digital 3D Stereo Enhancement |
| • | FIR filter programmability for simple tone control |
| • | Low power clock network operation if a 12 MHz or 13 MHz system clock is available |
| • | Read/write I
2C or SPI compatible control interface
|
| • | Automatic headphone & microphone detection |
| • | Support for internal and external microphones |
| • | Automatic gain control for microphone input |
| • | Differential audio I/O for external cellphone module |
| • | Mono differential auxiliary output |
| • | Stereo auxiliary inputs |
| • | Differential microphone input for internal microphone |
| • | Flexible audio routing from input to output |
| • | 32 Step volume control for mixers in 1.5 dB steps |
| • | 16 Step volume control for microphone in 2 dB steps |
| • | Programmable sidetone attenuation in 3 dB steps |
| • | Two configurable GPIO ports |
| • | Multi-function IRQ output |
| • | Micro-power shutdown mode |
| • | Available in the 4 x 4 mm 49 bump micro SMDxt package |
Description The LM49370 is an integrated audio subsystem that supports both analog and digital audio functions. The LM49370 includes a
high quality stereo DAC, a mono ADC, a stereo headphone amplifier, which supports output cap-less (OCL) or AC-coupled (SE)
modes of operation, a mono earpiece amplifier, and an ultra-low EMI spread spectrum Class D loudspeaker amplifier. It is designed
for demanding applications in mobile phones and other portable devices.
The LM49370 features a bi-directional I
2S interface and a bi-directional PCM interface for full range audio on either interface. The LM49370 utilizes an I
2C or SPI compatible interface for control. The stereo DAC path features an SNR of 85 dB with an 18-bit 48 kHz input. In SE
mode the headphone amplifier delivers at least 33 mWRMS to a 32Ω single-ended stereo load with less than 1% distortion (THD+N) when A_VDD = 3.3V. The mono earpiece amplifier delivers at least 115mWRMS to a 32Ω bridged-tied load with less than 1% distortion (THD+N) when A_VDD = 3.3V. The mono speaker amplifier delivers up to 490mW into an 8Ω load with less than 1% distortion when LS_VDD = 3.3V and up to 1.2W when
LS_VDD = 5.0V.
The LM49370 employs advanced techniques to reduce power consumption, to reduce controller overhead, to speed development time,
and to eliminate click and pop. Boomer audio power amplifiers were designed specifically to provide high quality output power
with a minimal amount of external components. It is therefore ideally suited for mobile phone and other low voltage applications
where minimal power consumption, PCB area and cost are primary requirements.
Key Specification
|
PHP (AC-COUP) (A_VDD = 3.3V, 32Ω, 1% THD)
|
33 mW
|
|
PHP (OCL) (A_VDD = 3.3V, 32Ω, 1% THD)
|
31 mW
|
|
PLS ( LS_VDD = 5V, 8Ω, 1% THD)
|
1.2 W
|
|
PLS (LS_VDD = 4.2V, 8Ω, 1% THD)
|
900 mW
|
|
PLS (LS_VDD = 3.3V, 8Ω, 1% THD)
|
490 mW
|
|
Shutdown Current
|
0.8 µA
|
|
PSRRLS (217 Hz, LS_VDD = 3.3V)
|
70 dB
|
|
SNRLS (AUX IN to Loudspeaker)
|
90 dB (typ)
|
|
SNRDAC (Stereo DAC to AUXOUT)
|
85 dB (typ)
|
|
SNRADC (Mono ADC from Cell Phone In)
|
90 dB (typ)
|
|
SNRHP (Aux In to Headphones)
|
98 dB (typ)
|
Applications
| • | Smart phones |
| • | Mobile Phones and Multimedia Terminals |
| • | PDAs, Internet Appliances and Portable Gaming |
| • | Portable DVD/CD/AAC/MP3 Players |
| • | Digital Cameras/Camcorders |
|
Also Recommended
| LM49352▲ | Lower Power Cusumption Headphone, Higher Output Power |
|
|
LM49352
