Semiconductor memory device capable of suppressing a coupling effect of a test-disable transmission line
View Patent ↗Semiconductor device and semiconductor memory device include a plurality of internal circuits configured to perform test operations in response to their respective test mode signals and a plurality of test-mode control units configured to control the test operations of the internal circuits to be disabled in response to a test-off signal.
1. A semiconductor memory device, comprising:
an internal circuit configured to perform a test operation in response to a test mode signal;
a test mode control unit coupled to the internal circuit; and
a test-off signal transmission line configured to transmit a test-off signal to the test mode control unit,
wherein the test mode control unit is configured to disable, regardless of an activation of the test mode signal, the test operation of the internal circuit in response to the test-off signal being activated,
wherein the test mode control unit includes a NOR gate for NORing the test-off signal and the test mode signal to control the internal circuit.
2. The semiconductor memory device as recited in claim 1 , further comprising:
a test mode signal transmission line configured to transmit the test mode signal to the test mode control unit, wherein the test mode control unit enables the test operation of the internal circuit in response to the test-off signal being deactivated and the test mode signal being activated.
3. The semiconductor memory device as recited in claim 1 , wherein, in response to the test-off signal being activated, the test mode control unit deactivates the internal circuit and prevents the test mode signal from being transmitted to the internal circuit.
4. The semiconductor memory device as recited in claim 3 , wherein the test mode control unit is adjacent to the internal circuit such that the test mode control unit controls the internal circuit.
5. The semiconductor memory device as recited in claim 1 , wherein the test-off signal is activated in normal operations of the internal circuit to prevent an entry into the test operation of the internal circuit.
6. A semiconductor memory device, comprising:
a plurality of internal circuits configured to each perform a respective test operation in response to a respective test mode signal;
a plurality of test mode control units coupled to the plurality of internal circuits, respectively; and
a test-off signal transmission line configured to transmit a test-off signal to the plurality of test mode control units, the plurality of test mode control units configured to disable, regardless of an activation of the test mode signal, the respective test operations of the plurality of internal circuits in response to the test-off signal being activated,
wherein each of the test mode control units includes a NOR gate for NORing the test-off signal and a corresponding one of the test mode signals for a corresponding one of the internal circuits.
7. The semiconductor memory device as recited in claim 6 , further comprising:
a plurality of test mode signal transmission lines configured to transmit a plurality of test mode signals to respective ones of the plurality of test mode control units, the plurality of test mode control units enabling the respective test operations of the plurality of internal circuits in response to the test-off signal being deactivated and the respective test mode signal being activated.
8. The semiconductor memory device as recited in claim 6 , wherein, in response to the test-off signal being activated, the test mode control units deactivate the internal circuits and prevent the test mode signals from being transmitted to respective ones of the plurality of internal circuits.
9. The semiconductor memory device as recited in claim 6 , wherein the test-off signal is activated in normal operations of the internal circuits to prevent an entry into the test operations of the internal circuits.