采用TXB0106做电平转换,一端接3.3V的处理器SPI,另外一端接ADS1211的5V的SPI,进行转换,其中SPI时钟在未进入TXB0106时,时钟良好,可是测量经过TXB0106后的波形,已经不再是方波,二是锯齿波,并且频率跳动请问专家这是为何?
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采用TXB0106做电平转换,一端接3.3V的处理器SPI,另外一端接ADS1211的5V的SPI,进行转换,其中SPI时钟在未进入TXB0106时,时钟良好,可是测量经过TXB0106后的波形,已经不再是方波,二是锯齿波,并且频率跳动请问专家这是为何?
电压和速率都没问题,另外,TXB0106datasheet中有一句:For proper operation, the device driving the data I/Os of the TXB0106 must have drive strength of at least ±2 mA.也就是说,电流流入TXB0106的IO端从low到high的过程至少需要2mA的电流,反之亦然,所以看下处理器SPI口的输出能力。如果不够的话,可以采用SN74AVC4T774.