NXP NE58633降噪D类耳机驱动放大方案

NXP 公司的NE58633是立体声降噪D类BTL耳机驱动放大器,每路包括了D类BTL耳机驱动放大器, 驻极体麦克风低噪音前置放大器,反馈降噪电路和音乐放大器输入.NE58633工作电压从0.9V到1.7V,具有片上DC/DC升压转换器和内部基准电压,电流消耗仅为4.4mA,能向16或32欧姆负载提供800mVrms的驱动,可用在各种手提音频设备如手机,MP3和多媒体播放器等.本文介绍了NE58633的主要特性,方框图,应用电路图以及性能测试电路图.

NE58633: Noise reduction class-D headphone driver amplifier

The NE58633 is a stereo, noise reduction, class-D, Bridge-Tied Load (BTL) headphone driver amplifier. Each channel comprises a class-D BTL headphone driver amplifier, an electret microphone low noise preamplifier, feedback noise reduction circuit and a music amplifier input.

The NE58633 operates with a battery voltage of 0.9 V to 1.7 V. The chip employs an on-chip DC-to-DC boost converter and internal Vref voltage reference which is filtered and output to ground for noise decoupling. It features mute control and plop and click reduction circuitry. The gain of the microphone amplifier and filter amplifier is set using external resistors. Differential architecture provides increased immunity to noise.

The NE58633 is capable of driving 800 mVrms across a 16 ohm or 32 ohm load and provides ElectroStatic Discharge (ESD) and short-circuit protection.

It is available in the 32-pin HVQFN32 (5 mm x5 mm x0.85 mm) package suitable for high density small-scale layouts and is an ideal choice for noise reduction headphones and educational audio aids.

NE58633主要特性 :

Low current consumption of 4.4 mA

0.9 V to 1.7 V battery operating voltage range

1 % THD+N at VO = 1 VM driving 16ohm with a battery voltage of 1.5 V

10 % THD+N at 800 mVrms output voltage driving 16 ohm and 32 ohm loads with a battery voltage of 1.5 V

Output noise voltage with noise reduction circuit typically 31 mVrms for Gv(cl) = 25 dB

On-chip mute function

Plop and click reduction circuitry

Class-D BTL differential output configuration

Electret microphone noise reduction polarization amplifier with external gain adjustment using resistors

Music and filter amplifier with external gain adjustment using resistors

DC-to-DC converter circuitry (3 V output) with 2.5 mA (typical) load current

Internal voltage reference pinned out for noise decoupling

Available in HVQFN32 package



图1.NE58633方框图



图2.NE58633应用电路图



图3.NE58633测试电路图