Semiconductor memory device
View Patent ↗Disclosed is a semiconductor memory device which includes a sense amplifier, arranged between a first mat and a second mat, switches for controlling the connection between first and second bit lines of each of the first and second mats on one hand and the sense amplifier on the other, and a control unit for exercising control so that, when an input test mode signal indicates a test mode, both the switch associated with the selected mat and the switch associated with the non-selected mat will be turned on.
1. A semiconductor memory device comprising:
first and second mats, each including a plurality of memory cells;
a sense amplifier shared by said first and second mats;
a first switch for controlling the connection between said sense amplifier and a bit line of said first mat;
a second switch for controlling the connection between said sense amplifier and a bit line of said second mat;
a control circuit for receiving a test mode signal and performing control so that in case of said test mode signal indicating a test mode, said first and second switches, one of which is associated with the selected mat and the other of which is associated with the non-selected mat are both set to be in an on state;
a first driver circuit for receiving a first mat selection signal, and outputting a signal which is for turning said first switch on when said first mat selection signal indicates a selected state;
a second driver circuit for receiving a second mat selection signal, and outputting a signal which is for turning said second switch on when said second mat selection signal indicates a selected state;
a first logic circuit for receiving an output signal of said first driver circuit and said test mode signal, said first logic circuit activating an output without dependency on the value of the output signal of said first driver circuit when said test mode signal indicates the test mode, said first logic circuit outputting a signal corresponding to the output of said first driver circuit when said test mode signal indicates a normal operation; and
a second logic circuit for receiving an output signal of said second driver circuit and said lest mode signal, said second logic circuit activating an output without dependency on the value of the output signal of said second driver circuit when said test mode signal indicates a test mode, said second logic circuit outputting a signal corresponding to the output of said second driver circuit when said test mode signal indicates a normal operation mode;
output signals of said first and second logic circuits being supplied to control terminals of said first and second switches as signals controlling the on/off of said first and second switches.
2. The semiconductor memory device according to claim 1 , wherein said control circuit performs control so that in case of said test mode signal indicating a normal operation, only the one of the first and second switches associated with the selected mat is set to be in an on state.
3. The semiconductor memory device according to claim 1 , wherein, in the test mode, data of a memory cell of the selected one of the first and second mats is read by said sense amplifier, with said first and second switches both being turned on.
4. The semiconductor memory device according to claim 1 , wherein said first switch includes a pair of transfer gates inserted between said sense amplifier and a bit line pair of said first mat and having gate terminals connected in common to an output of said first logic circuit; and
said second switch includes a pair of transfer gates inserted between said sense amplifier and a bit line pair of said second mat and having gate terminals connected in common to an output of said second logic circuit.