Freescale公司的SGTL5000是集成了耳机放大器的低功耗立体声CODEC,提供线路输入,麦克风输入,线路输出,耳机输出和数字I/O,是手持产品的完整的音频解决方案.模拟输入ADC的SNR为- 85dB,具有环绕,低音,音质控制/参数均衡/图像均衡以及时钟控制等,主要用在手持导航设备(PND),电子书,智能手机,平板电脑和GPS等.本文介绍了SGTL5000主要特性,方框图, 20QFN和32QFN封装的典型应用电路, 平板电脑方框图以及SGTL5000评估平台主要特性和电路图.
The SGTL5000 is a Low Power Stereo Codec with Headphone Amp from Freescale, and is designed to provide a complete audio solution for portable products needing line-in, mic-in, line-out, headphone-out, and digital I/O. Deriving it’s architecture from best in class, Freescale integrated products that are currently on the market. The SGTL5000 is able to achieve ultra low power with very high performance and functionality, all in one of the smallest footprints available. Target markets include portable media players, GPS units, and smart phones.
Features such as capless headphone design and an internal PLL, help lower overall system cost.

SGTL5000主要特性:
Analog Inputs
• Stereo Line In - Support for external analog input
• Stereo Line In - Codec bypass for low power
• MIC bias provided (5.0 x 5.0 mm QFN, 3.0 x 3.0 mm QFN TA2)
• Programmable MIC gain
• ADC - 85 dB SNR (-60 dB input) and -73 dB THD+N (VDDA = 1.8 V) Analog Outputs
• HP Output - Capless design
• HP Output - 45 mW max into 16 ohm load @ 3.3 V
• HP Output - 100 dB SNR (-60 dB input) and -80 dB THD+N (VDDA = 1.8 V, 16 ohm load, DAC to headphone)
• Line Out - 100 dB SNR (-60 dB input) and -85 dB THD+N (VDDIO = 3.3 V) Digital I/O
• I2S port to allow routing to Application Processor Integrated Digital Processing
• Freescale Surround, Freescale Bass, tone control/ parametric equalizer/graphic equalizer Clocking/Control
• PLL allows input of an 8.0 MHz to 27 MHz system clock - Standard audio clocks are derived from PLL
Power Supplies
• Designed to operate from 1.62 to 3.6 volts

SGTL5000优势:
High performance at low power for DAC-to-HP
101 dB SNR @ < 9.3 mW
Extremely low power modes
98 dB SNR @ < 4 mW
Small PCB footprint
3 mm x 3 mm QFN
Allows for no-cost system customization

SGTL5000应用:
Portable Navigation Devices
eReaders
Media Phones
Smartphones
Tablets
Global Positioning System (GPS)

图1.SGTL5000简化方框图

图2.SGTL5000简化应用框图


图3.20QFN封装的SGTL5000典型应用电路

图4.20QFN封装的SGTL5000最低功耗应用电路


图5.32QFN封装的SGTL5000最低功耗应用电路(1)

图6.32QFN封装的SGTL5000最低功耗应用电路(2)

图7.平板电脑方框图

SGTL5000评估平台
The evaluation platform is designed to allow the user to test the features and performance
of the SGTL5000 audio codec. The evaluation board can be used as a demo or development platform.

SGTL5000评估平台主要特性:
• SGTL5000 Audio Codec
• LINEIN RCA analog input jack
• LINEOUT RCA analog output jack
• Selectable mini-jack or onboard microphone input
• Stereo headphone mini-jack analog output, with optional capless design circuitry
• Two-row headers for buffered I2S digital input/output
• Support for onboard or external MCLK source
• USB to I2C/SPI communication port
• 5V input voltage through either internal LDO regulators, or external individual Supplies

图8. SGTL5000评估平台外形图

图9. SGTL5000评估平台方框图

图10. SGTL5000评估平台电路图(1)


图11. SGTL5000评估平台电路图(2)

图12. SGTL5000评估平台电路图(3)

图13. SGTL5000评估平台电路图(4)

图14. SGTL5000评估平台电路图(5)

图15. SGTL5000评估平台电路图(6)