AKM 公司的AK4223是高性能低功耗音頻6:2和視頻6:2開關，采用差分輸入電路，音視頻可分開。音頻部分有差分輸入電路，音頻LPF和odB/-6dB增益放大器，S/（N+D）為90dB，動態范圍94dB;視頻部分包括輸入箝位電路，6dB放大器和視頻驅動器，信噪比65dB， 主要用在汽車AV系統和汽車導航系統。本文介紹了AK4223主要特性，方框圖，典型連接圖以及評估板AKD4223-A主要功能，方框圖，電路圖和元件布局圖。
The AK4223 is an AV switch with 6:2 audio and 6:2 video switches. High performances with low power consumption are achieved by CMOS process. Integrated differential input circuits in audio and video blocks can separate the external ground noise. In audio block, a differential input circuit, audio LPF and 0dB/-6dB gain amplifier are integrated eliminating the needs for external LPF for audio outputs. In video block, an input clamp circuit, 6dB amplifier and video driver are integrated, and they also eliminate the need for external circuits. The AK4223 is offered in a space saving small 48-pin LQFP package, ideal for car navigation applications.
AK4223主要特性：
1. Audio Section
• Selector with 6 inputs and 2 outputs
• Differential Input Circuit for Ground Noise Canceling
• LPF Circuit for Audio signals
• Output Gain Control: 0dB ∼ - 6dB, -1dB Step
• S/(N+D): 90dB (@0dBV)
• Dynamic Range: 94dB
• Channel-Independent Mute Function
2. Video Section
• Selector with 6 inputs and 2 outputs
• Six Composite Signal Inputs
• On-Chip Sync-tip Clamp Circuit
• Video Drivers for Composite Signal Output (+6dB/+3dB/0dB/-3dB)
• Output Gain Control: -1dB ∼ +1dB, 0.1dB Step
• LPF Circuit for Video signals (Bandwidth: 6MHz)
• S/N: 65dB
• Channel-Independent Mute Function
3. Control Section
• Serial μP I/F (I2C)
4. Power Supply: 7.5V ∼ 9.5V
5. Ta = -40 ∼ 85℃
6. Package: 48pin LQFP
圖1。AK4223 方框圖
圖2。AK4223 典型連接圖
評估板AKD4223-A
AKD4223-A is an evaluation board for AK4223 that has various 6:2 audio and 6:2 video switches. This board can achieve the interface with AV systems via RCA connectors.
評估板AKD4223-A功能：
• RCA connectors for analog audio: 6 inputs 2 outputs
• RCA connectors for video: 6 inputs, 2 outputs
• 10-pin header for I2C serial control
圖3。評估板AKD4223-A方框圖
圖4。評估板AKD4223-A電路圖（1）
圖5。評估板AKD4223-A電路圖（2）
圖6。評估板AKD4223-A電路圖（3）
圖7。評估板AKD4223-A元件布局圖 |
