Semiconductor memory device having preamplifier with improved data propagation speed
AssigneeRenesas Technology Corp.
InventorTakashi Kono
Life of this patent
Estimating the term…
Abstract
A preamplifier includes an amplifier circuit amplifying a signal level of read data, a latency shifter outputting the read data onto a data line pair in response to an internal signal determining a timing of outputting the read data onto the data bus pair, and a driver outputting the read data onto the data bus pair. The amplifier circuit receives the internal signal and outputs the read data onto the data line pair while bypassing the latency shifter when the internal signal is already at high level at the timing when the signal level of the read data is amplified. As a result, a semiconductor memory device can speed up propagation of the read data from the preamplifier onto the data bus pair in a high frequency operation.
Claims7
A semiconductor memory device allowing data input/output in synchronization with a rise and a fall of an external clock, comprising:
- a memory cell array storing data;
- a control circuit producing first and second signals based on an adjacent clock cycle as a starting point;
- a preamplifier amplifying read data read from said memory cell array to be output onto a data bus based on said first and second signals;
- and
- a data output circuit externally outputting said read data output onto said data bus, wherein
- said preamplifier
- amplifies a signal level of said read data based on said first signal and outputs said read data having the amplified signal level onto said data bus based on said second signal when a timing of receiving said second signal is later than a timing of receiving said first signal, and
- amplifies a signal level of said read data based on said first signal and outputs said read data having the amplified signal level onto said data bus based on the first signal when a timing of receiving said second signal is earlier than a timing of receiving said first signal.
Dependencies are inferred from the claim text.