Macronix International Co., Ltd.

Nien-Chao Yang

Cheng-Lin Chung

Ful-Long Ni

Yu-Wei Lee

Hsiao-Ming Lin

Lai-Ching Lin

Jing-Wen Chen

The present invention provides a read-only memory array having a flat-type structure. The read-only memory array comprises at least two memory banks having a plurality of memory cells. At least two inter-bank transistors are coupled to the two memory banks and shared by the two memory banks. Each inter-bank transistor is used for enabling to select the memory cells of the two memory banks. At least a contact commonly is coupled to the two memory banks through the two inter-bank transistors.

High density mask ROM having flat-type bank select

A low power latch sense amplifier for electrically being coupled to a bit line of a memory cell array is disclosed. The low power latch sense amplifier comprises a common gate sense amplifier and an activated latch register. The common gate sense amplifier comprising a current source and a biased metal-oxide semiconductor is applied for sensing the current of the bit line. The current source and the biased MOS are coupled to a first node, and the common gate sense amplifier outputs a sensing signal at the first node. The activated latch register comprises a first clock signal-synchronized inverter which includes a first inverter and a first switch. The first inverter responds to the sensing signal, and the first inverter outputs a first inverter output signal. The first switch is controlled by a first set of control signal, and the first inverter output signal is corresponding to the sensing signal when the first switch is turned on.

Low power latch sense amplifier

A sense amplifier inverts the output from the pass transistor to control a pre-charge transistor. The combination of the inverter and pre-charge transistor pre-charges the output to a level just below the flip level of the following data latch circuit. If the data cell read is a low threshold cell (conductive or &ldquo;1&rdquo;), the output level does not significantly change, and the data is rapidly latched and read. If the data cell is a high threshold cell (non-conductive or &ldquo;0&rdquo;), the pass transistor shuts off and the output is pulled up above the flip level of the data latch circuit through a pull-up path. The pre-charge level is near the flip level, so the output does not have to be pulled up very far, thus reading a &ldquo;0&rdquo; is also fast. In one embodiment, the pull-up transistor is a p-channel MOSFET with the gate grounded, thus providing more constant current than a diode-connected configuration. In another embodiment, the pull-up transistor is operated as a current mirror using a cell in a mini array. The first inverter of the data latch circuit can be used in the feedback path to the precharge transistor, or a separate feedback inverter can be provided.

High-speed sense amplifier with auto-shutdown precharge path

A flat-cell nonvolatile semiconductor memory. The semiconductor memory includes a plurality of units. Each unit includes word lines, a main bit line, a ground line, sub-bit lines, memory cell columns, and bank-selecting switches. Word lines are disposed in parallel, and the main bit line and the ground line cross the word lines. Sub-bit lines are disposed substantially in parallel to the main bit lines. Each memory cell column includes a plurality of memory cells connected in parallel between respective adjacent two of the sub-bit lines. The bank-selecting switches are used to select one of the memory cell columns. The first one of the bank-selecting switches is disposed between the main bit line and the fourth sub-bit line. The second of the bank-selecting switches is disposed between the main bit line and the second sub-bit line. The third of the bank-selecting switches is disposed between the ground line and the fifth sub-bit line. The fourth of the bank-selecting switches is disposed between the ground line and the third sub-bit line. The fifth of the bank-selecting switch is disposed between the ground line and the third sub-bit line. The sixth bank-selecting switch is disposed between the ground line and the first sub-bit line. Wherein, the second, third, and fourth bank-selecting switches are controlled by a first selecting signal, and the first, fifth, and sixth bank-selecting switches are controlled by a second selecting signal.

Flat-cell nonvolatile semiconductor memory

An integrated circuit memory comprises an array of non-volatile memory cells arranged in rows and columns, and including a plurality of banks. There are a plurality of word lines along the plurality of rows in the array, and a plurality of array bit lines arranged along the plurality of columns. The array bit lines extend across the array, and include sense lines and ground lines. A plurality of bank bit lines is arranged along the plurality of columns. The bank bit lines extend across corresponding banks in the plurality of banks and are coupled to memory cells in the corresponding banks. A plurality of connection terminals are coupled to the array bit lines. For each array bit line there is at least one connection terminal per bank in the plurality of banks for which the array bit line will be used. A plurality of bank select transistors is provided to act as bank select circuitry. The bank select transistors are operable to selectively connect respective bank bit lines to corresponding connection terminals for array bit lines. The bank select transistors are characterized by allowing independent connection of bank bit lines to sense lines of the plurality of array bit lines, while minimizing the number of transistors in the sensing path. In embodiments described, the bank select transistors allow independent connection of the bank bit lines to both sense lines and ground lines in the plurality of array bit lines.

Bank selection structures for a memory array, including a flat cell ROM array

The sense amplifier of the present invention contains a circuit that can pre-charge its output to a default state (e.g., the '0' state) during one time period and sets the output to a second state in another time period only if there is a need to do so. In this sense amplifier, cell leakage (and not cell current) is used as reference. Further, only the second state needs to be developed. As a result, the sensing margin increases. One characteristics of the present sense amplifier is that different parts of the circuit is active during different time period. As a result, both noise and power consumption is reduced. The sense amplifier is coupled to a timing circuit that can provide appropriate timing signals to operate the sense amplifier. In addition, a power-on reset circuit is disclosed. This reset circuit is operative when power is first applied to the system. It causes the timing circuit to generates a timing signal so that valid data can be detected by the sense amplifier when power is turned on.

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Hsinchu, Taiwan

Nien-Chao Yang