I'm studying DRams and SRams at university and on the slides the lines where a data is read or written is called DQ. But whats does it means? Maybe D is for Data, but Q?


2 Answers 2


I think that the origin of the name comes from the convention for flip flops. On a D flipflop the data in pin is generally called D, and the data out pin, Q. Since the memories data bus is bidirectional, a data pin can be D when it is input or Q when it is output hence the name DQ.


I quote from this IBM article - http://www.archive.ece.cmu.edu/~ece548/localcpy/sramop.pdf

The DQ pins are used for data input and output. DQs on SRAMs come in two forms — on some devices, the inputs and outputs are separate, on others, they are common, with the input and output using the same pin on the memory device. All of IBM Microelectronics' SRAM offerings have common I/O.

Edit: Q is the normal designation for the output line of a flip flop, counter etc. D stands for Data.

  • \$\begingroup\$ Thank you for the reply. I understand what Dq lines do, but I would like to know the meaning of DQ. For example I have a signal called OE where it means "Output Enable" \$\endgroup\$
    – linofex
    Jan 22, 2017 at 16:30
  • 1
    \$\begingroup\$ Q is the normal designation for an output line for a flip flop, counter etc. D is obviously Data. \$\endgroup\$ Jan 22, 2017 at 16:39
  • 1
    \$\begingroup\$ The origin of the designation, Q, is discussed in this question electronics.stackexchange.com/questions/51625/… \$\endgroup\$ Jan 22, 2017 at 16:45

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