NXP公司的NE58633是立體聲降噪D類BTL耳機驅動放大器,每路包括D類BTL耳機放大器,駐極體麥克風低噪音前置放大器,反饋降噪電路以及音樂放大器輸入. NE58633的工作電壓為0.9V到1.7V,片內有DC/DC升壓轉換器和Vref基準電壓,還具有靜音控制和開關降噪電路. 麥克風放大器和濾波器放大器增益用外接電阻設定.本文介紹了NE58633主要特性,方框圖, 反饋應用電路圖, 前饋應用電路圖和測試電路圖.
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
圖1.E58633方框圖
圖2.NE58633反饋應用電路圖
圖3.NE58633前饋應用電路圖
圖4.NE58633測試電路圖
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