MAXIM公司的MAX13325是一款可靠差分接口的汽车级双路音频驱动器器件，该器件具有差分输入及输出、集成输出诊断功能、采用IIC接口或独立模式控制。输出诊断功能包含短路到地、短路到电池、过流、过温和过度补偿。输出端可驱动4nF对地负载，差分输出可驱动3nF负载。该芯片满足IEC 61000-4-2标准。本文首先介绍芯片的简介、特性、内部框图及应用领域，并给出相应设计方案的设计原理图、元器件列表及PCB元件布局图。

The MAX13325/MAX13326 dual audio line drivers provide a reliable differential interface between automotive audio components. The devices feature differential inputs and outputs, integrated output diagnostics, and are controlled using an I2C interface or operate in stand-alone mode. The outputs can deliver up to 4VRMS into 100I loads.

The MAX13325 buffers analog audio signals for transmission over long cable distances with a fixed gain of 12dB, whereas the MAX13326 provides a 0dB fixed gain. The diagnostics on the outputs report conditions on a per channel basis, including short to GND, short to battery, overcurrent, overtemperature, and excessive offset. The output amplifiers can drive capacitive loads up to 4nF to ground and 3nF differentially.

The outputs are protected according to IEC 61000-4-2 Q8kV Contact Discharge, and Q15kV Air Gap. The MAX13325/MAX13326 are specified from -40NC to +105NC and are available in a 28-pin TSSOP package with an exposed pad.

MAX13325主要特性：

•  Comprehensive Programmability and Diagnostics Using I2C Interface
•  Autoretry Function in Stand-Alone Mode
•  Drive Capacitive Loads ≤ 3nF Differentially, ≤ 4nF to Ground
•  112dB Signal-to-Noise Ratio
•  Low 0.002% THD at 4VRMS into 2.7kI Loads
•  High PSRR (70dB at 1kHz)
•  High CMRR (80dB at 1kHz)
•  Low Output Noise (3μVRMS), MAX13326
•  Excellent Channel-to-Channel Matching
•  Load-Dump Transient Protection
•  Protected Output Against Various Short-Circuit Conditions
•  ESD Protection for ±8kV Contact Discharge, ±15kV Air Gap
•  Long-Distance Drive Capability Typically Up to 15m or Greater
•  Noise-Rejecting Differential Inputs and Outputs
•  Low-Power Shutdown Mode < 10μA
•  Hardware or Software MUTE Function
•  28-Pin TSSOP Package with Exposed Pad

MAX13325应用：

•  Automotive Radio
•  Rear Seat Entertainment
•  Professional Remote Audio Amplifiers

 

图1. MAX13325内部方框图

MAX13325方案介绍：

The MAX13325 evaluation kit (EV kit) provides a proven design to evaluate the MAX13325 dual, audio line driver,which provides a robust differential interface between automotive audio components. The EV kit also includes WindowsM 2000-, Windows XPM-, and Windows VistaMcompatible software that provides a simple graphical user interface (GUI) for exercising the features of the MAX13325.

The MAX13325 EV kit comes with a MAX13325GUI/V +installed. Contact the factory for free samples of the pincompatible MAX13326GUI/V+ to evaluate this device.

Features：

•  Fully Differential Inputs and Outputs
•  Jumper-Selectable I2C Slave Address
•  On-Board USB Interface Circuit Generates I2C-Compatible Signals
•  PCB Pads for Audio Inputs and Outputs
•  PCB Pads for User-Supplied I2C-Compatible Signals
•  Windows 2000-, Windows XP-, and Windows Vista (32-Bit)-Compatible Software
•  USB-PC Connection (Cable Included)
•  Proven PCB Layout
•  Fully Assembled and Tested

MAX13325方案原理图：




  

图2. NCP1255方案原理图

MAX13325方案材料清单：



PCB元件布局图：