SD NAND 的硬件电路设计需要综合考虑接口类型、电源管理、信号完整性、ESD 保护等多个维度。以下是针对工业级应用的完整设计指南:
SD NAND 的供电设计需满足其工作电压范围及电流波动需求,典型设计如下:
+-----+ | | | VCC |----+ | | | +-----+ | +--------+ +-----+ +----| LDO |----|10μF |--+-- VDD_SD (3.3V) | |AMS1117 | +-----+ | +-----+ | +--------+ | | | | | | VIN +----+ | | | | +-----+ | +-----+ |100nF| +-----+ | GND
关键设计要点:
+--------+ +--------+ | | | | | MCU | | | | | | | | CS +------------------+ CS | | | | | | SCLK +------------------+ SCLK | | | | | | MOSI +------------------+ DATA | | | | | | MISO +------------------+ CMD | | | | | +--------+ +--------+ | | | | +-----+ |10KΩ | +-----+ | GND
SPI 接口设计要点:
+--------+ +--------+ | | | | | MCU | | | | | | | | CLK +------------------+ CLK | | | | | | CMD +------------------+ CMD | | | | | | DAT0 +------------------+ DAT0 | | | | | | DAT1 +------------------+ DAT1 | | | | | | DAT2 +------------------+ DAT2 | | | | | | DAT3 +------------------+ DAT3 | | | | | +--------+ +--------+
SDIO 接口设计要点:
+--------+ | | +-----------+ TVS +-----------+ | | SMBJ5.0CA| | | +--------+ | | | +-----+-----+ +-----+-----+ | | | | | SD NAND | | MCU | | | | | +-----+-----+ +-----+-----+ | | | +--------+ | +------+ 22Ω +---------------+ | 电阻 | +------+ +---------------+ | | | | | +--------+ | +------+----+ 0.1μF +---+ | +--------+ | GND
ESD 保护设计要点:
关键 PCB 布局规则:
层叠设计:
走线宽度:
间距要求:
过孔设计:
分区隔离:
设计验证步骤:
通过以上设计要点和验证步骤,可以确保 SD NAND 在工业环境下稳定可靠地工作。在实际设计中,还需参考具体 SD NAND 型号的 datasheet 进行针对性优化。