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Maxim MAX97220差分输入耳机放大器解决方案

2011-07-17
作者:Maxim公司
</a>放大器" title="放大器">放大器" title="放大器">放大器,5V电源时能以3VRMS驱动1K欧姆线路负载, 3.3V电源时能以2VRMS驱动600欧姆线路负载,工作电压2.5V-5.5V, DirectDrive输出,不需要隔直流电容,THD+N优于90dB,18位SNR性能达112dB,主要用于STB,蓝光和DVD播放器,LCD电视和音频设备.本文介绍了MAX97220主要特性, 功能方框图, MAX97220A评估板主要特性,电路图,材料清单和PCB元件布局图.

The MAX97220A/B is a differential input DirectDrive® line driver/headphone amplifier. This device is capable of driving line level loads with 3VRMS into 1kI with a 5V supply and 2VRMS into 600I loads from a 3.3V supply. A headphone load is capable of being driven with 125mW into 32I with a 5V supply. The IC is offered with an inter­nally fixed 6dB gain or an externally set gain through external resistors. The external gain setting nodes can also be used to configure filters for set-top box applica­tions. The IC has exceptional THD+N over the full audio bandwidth.

Two versions of the IC are available with different turn-on times (tON). The A and C versions for headphone applications feature a tON of 5.5ms while the B and D versions, intended for set-top-box applications, feature a 130ms tON. An on-chip charge pump inverts the power-supply input, creating a negative rail. The output stage of the amplifier is powered between the positive input sup­ply and the output of the charge pump. The bipolar sup­plies bias the output about ground, eliminating the need for large, distortion-introducing output coupling capaci­tors. The IC powers on and off without clicks or pops.

The IC is available in a 3mm x 3mm x 0.8mm, 16-pin TQFN and is specified over the extended -40NC to +85NC temperature range.

MAX97220主要特性:

Output Power 125mW into 32I with a 5V Supply

3VRMS Output Drive into 1kI with a 5V Supply

2VRMS Output Drive into 600I with a 3.3V Supply

Fully Differential Inputs

Fixed or Externally Adjustable Gain with No Clicks or Pops

Wide 2.5V to 5.5V Operating Range

DirectDrive Outputs Eliminate DC-Blocking Capacitors

Flat THD+N, Better Than 90dB in the Audio Band

18-Bit SNR Performance, 112dB

Footprint Compatible with the MAX9722

Simple Multimedia Interfaces

MAX97220应用:

Set-Top Boxes

Blu-rayK and DVD Players

LCD Televisions

Prosumer Audio Devices

图1.MAX97220功能方框图

图2.MAX97220简化方框图

图3.MAX97220A和MAX9722 PCB布局图

图4.MAX97220A/B增益设定图

MAX97220A评估板

The MAX97220A evaluation kit (EV kit) is a fully assembled and tested circuit board that evaluates the MAX97220A differential input DirectDrive® line driver/headphone amplifier. The device is capable of driving 125mW into 32Ω, or 3VRMS into 600Ω load, with a 5V supply.

The EV kit provides an externally set gain, is powered from a 2.5V to 5.5V single power supply, and includes a shutdown input. The EV kit also evaluates the MAX97220B, MAX97220C, and MAX97220D devices. Request a free MAX97220B, MAX97220C, and/or MAX97220D IC sample from the factory when ordering the EV kit.

MAX97220A评估板主要特性:

2.5V to 5.5V Single-Supply Operation

3VRMS Output Drive Into 600ω Load

125mW Headphone Amplifier

Fully Differential Inputs

Externally Adjustable Gain

Low-Power Shutdown Input

Evaluates the MAX97220B, MAX97220C, and MAX97220D (with IC Replacement)

Fully Assembled and Tested

图5.MAX97220A评估板电路图
MAX97220A评估板材料清单(BOM):


图6.MAX97220A评估板PCB元件布局图
详情请见:
http://datasheets.maxim-ic.com/en/ds/MAX97220A-MAX97220D.pdf

http://datasheets.maxim-ic.com/en/ds/MAX97220AEVKIT.pdf



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