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D类BTL耳机放大器,驻极体麦克风低噪音前置放大器,反馈降噪电路以及音乐放大器输入. NE58633的工作电压为0.9V到1.7V,片内有DC/DC升压转换器和Vref基准电压,还具有静音控制和开关降噪电路. 麦克风放大器和滤波器放大器增益用外接电阻设定.本文介绍了NE58633主要特性,方框图, 反馈应用电路图, 前馈应用电路图和测试电路图.

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 16 ;with a battery voltage of 1.5 V
10 % THD+N at 800 mVrms output voltage driving 16 61472;and 32 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.E58633方框图



图2.NE58633反馈应用电路图



图3.NE58633前馈应用电路图



图4.NE58633测试电路图