VTT是线路终结电压。VREF就是参考电压，加上DDR就是通向DDR内存的，直接的DDR上一般就不加DDR了。SMB...
Vref偏移对DDR会造成什么影响,其中有比较重要的一个点就是会影响setuptime和holdtime,这两个参数和Vref又有什么关系呢,还有JEDEC中讲的derating又是什么东西呢? setuptime和holdtime对我们判断时序裕量是一个比较关键的数值。一般JEDEC里面会对于setuptime和holdtime做比较详细的描述,如下图所示, 从上图中,我们可以看...
A method is provided for performing memory operations in response to instructions to perform a double data rate (DDR) memory reference voltage training in the voltage domain by a processing device and determining a DDR memory reference voltage and a DDR memory delay time based upon the memory ...
对于Spartan 6到单个DDR2或DDR3（即点对点），我建议：信号FPGA端DRAM端 DQ，DQS，DM内部串联和并联...
This delay that you are seen is probably caused by a big capacitance in the layout VREFDDR line, I believe that this delay can probably be adjusted by modifying the output capacitor value on VREFDDR pin. Try using a lower value capacitor. Have a great day,Jose Reyes ---Note: If this ...
A method is provided for performing memory operations in response to instructions to perform a double data rate (DDR) memory reference voltage training in the voltage domain by a processing device and determining a DDR memory reference voltage and a DDR memory delay time based upon the memory ...
本发明公开了一种DDR接口电路用自动调整参考电平VREF的方法,数据从控制端发送到存储端时,控制端读取控制端的驱动控制和存储端的终端阻抗控制,得到驱动电阻大小和终端阻抗大小,计算直流分压电平,控制端通过VREF控制信号在存储端产生相同电平的VREF;数据从存储端发送到控制端时,控制端读取存储端的驱动控制和控制端的终端...
本发明公开了一种DDR4DIMM的VREF供电电路,包括电阻分压电路,用于输出初始参考电压;与电阻分压电路的输出端连接的电压跟随器,用于对初始参考电压进行电压跟随得到参考电压VREF.可见,本发明在电阻分压电路的基础上还增加了一个电压跟随器,电压跟随器使得VREF供电电路的输出阻抗降低,驱动电流增大,驱动能力增强,抗干扰能力...
A method is provided for performing memory operations in response to instructions to perform a double data rate (DDR) memory reference voltage training in the voltage domain by a processing device and determining a DDR memory reference voltage and a DDR memory delay time based upon the memory ...