< /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 3V _RMSinto 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
和
http://datasheets.maxim-ic.com/en/ds/MAX97220AEVKIT.pdf