Abstract: An integrated circuit memory having a plurality of memory cells, output timing control means including frequency measurement means providing a frequency measurement count corresponding to a first frequency of the external clock signal and delay control means generating a delayed clock signal at the first frequency, wherein the delayed clock signal is delayed in time from the external clock signal in proportion to the first frequency, and data output control means outputting data from the plurality of memory cells responsive to the delayed clock signal. A method for adjusting output timing in a memory device including the steps of receiving an external clock signal, measuring a frequency of the external clock signal, generating a frequency count, determining an output delay proportional to the frequency, and generating an output clock at the external frequency and delayed from the external clock signal in proportion to the frequency.

Abstract: A pipelined dual port integrated circuit memory (20) includes an array (30) of static random access memory (SRAM) cells. A control circuit (32) controls access to the memory cells, where substantially simultaneous requests for access are serviced sequentially within a single cycle of a clock signal of a data processor that is accessing the memory (20). An address collision detector (110) uses both a differential amplifier (360) included within a D-flip-flop circuit (114) and a reference voltage provided by a reference voltage circuit (365) to compare addresses provided to the two ports, and generates a match signal that is used for determining which of the two ports are serviced first, independent of which port is read from, or written to. Because dual port functionality is obtained using a single port SRAM array (30), the memory (20) may be manufactured using relatively less integrated circuit surface area, and therefore at a lower cost.

Abstract: Method and apparatus for amplifying a signal (50) to produce a latched digital signal (46). In one embodiment, an output stage circuit (24) of memory (10) includes a differential amplifier circuit (100), a level converter (102), a timing circuit (104), a clock-free latch (106), a high impedance control circuit (108), a high impedance control circuit (110), and an output driver (112). Output stage (24) requires one clock signal to function. Alternate embodiments may skew the disabling edge of the clock to improve the speed characteristics of output stage (24). In one embodiment, signal (50) is a differential pair of signals provided from a memory bit cell array (12).

Abstract: A circuit having a combined level conversion and logic function (37, 90, 101, 102, and 103) receives a differential CMOS level input signal, and an input signal having a relatively small logic swing, performs a logic operation, and provides a single-ended CMOS output signal. The circuit (37) includes a CMOS switching portion (71) and a small signal switching portion (75) connected to provide a CMOS output signal that is the result of a logical operation of the input signals. The circuits (37, 90, 101, 102, and 103), eliminate the need for a separate level converter, reducing at least a gate delay, and insuring faster generation of the output signal. Also, the use of the circuit (37) having a combined level conversion and logic function allows the cache TAG (20) to provide read data at the same time that a match signal is generated.

Abstract: An output buffer circuit (20) has an output impedance that is adjustable. An external resistor (32) having a resistance that is a multiple of the desired output impedance is coupled to the output buffer circuit (20). A voltage across the resistor (32) is converted to a digital code using an analog-to-digital (A/D) converter (22). A digital code from the A/D converter (24) is used to adjust a resistance of a binary weighed transistor array (45) to match the resistance of the external resistor (32). A plurality of binary weighted output transistors (153, 154, 155) are selected in response to the digital code to adjust the output impedance to match the characteristic impedance of a load driven by the output buffer circuit (20). The output impedance is easily adjustable by changing the resistance of external resistor (32), allowing the output buffer circuit to drive various load impedances.

Abstract: A synchronous integrated circuit memory (30) has read global data lines shared between data read from a memory array (32) and data read from a data-in register (40) during a read-after-write. A comparator/latch (50) compares a new address to a previous address and generates an address match signal that is used to select match sense amplifiers (52) and deselect regular sense amplifiers (54). Relatively fast address comparison and address match signal generation is accomplished using a comparator/latch (50) for each column address signal, and emitter summing each match signal to provide the address match signal. The use of emitter summing reduces a number of gate delays, thus allowing the address match signal to be generated before the regular sense amplifiers (54) can be selected, and allowing the read global data lines to be shared without increasing the access time of the integrated circuit memory (30).

Abstract: A combined global data line load and multiplexer comprises a decoder, a bias generator circuit, at least one output signal line pair, and a plurality of switching portions. The decoder provides a plurality of select signals in response to a portion of an address, each select signal provided at either a logic high voltage or at a logic low voltage. For example, a X4 memory internally organized X8 uses one extra address bit to select between two sets of four global data line pairs to provide as outputs. The bias generator circuit provides a bias signal at a voltage between the logic high and the logic low voltages. The output signal lines are each coupled through a respective resistor to a power supply voltage terminal. Each switching portion provides substantially a differential current between corresponding global data lines to corresponding output signal lines in response to the bias voltage exceeding a voltage of a corresponding select signal.

Abstract: A BICMOS input stage includes a level shifting stage (35) and a level converter/buffer circuit (60). The input stage receives a single-ended GTL level input signal and a reference voltage, and in response, provides differential BICMOS level output signals. The input stage operates over a wide range of values for the reference voltage, does not require the generation of complex bias voltages, and provides well controlled output signals.

Abstract: A memory (30) includes input buffers (35, 38, 56), decoders (31, 32, 36), and a memory portion (34). The input buffers (35, 38, 56) include a delay circuit (82) which delays at least one transition of an input signal. The delay circuit (82) includes a compensation circuit (250) which compensates the delay circuit (82) for voltage, temperature, and processing variations. In one embodiment, the delay circuit (82) includes a CMOS inverter (102, 103) with an additional transistor (101) coupled between a source of an inverter transistor (102) and a corresponding power supply voltage. The compensation circuit (250) provides a bias voltage to bias a gate of the transistor (101) to determine the delay of the delay circuit (82). The compensation circuit (250) provides the bias voltage as that voltage which biases the transistor (101) to conduct a precision reference current.

Abstract: A bipolar complementary metal oxide semiconductor (BICMOS) sense circuit for sensing data on read data lines during a read cycle of a memory comprises a load portion and a sense amplifier portion. In one form, the load portion couples true and complement read data lines to a first voltage in response to a start of a read cycle. When the true and complement read data lines exceed a predetermined voltage, the sense amplifier is enabled. The load portion becomes inactive when the voltage on the read data lines reaches approximately the first voltage. Then a selected memory cell provides a differential voltage on a bit line pair, which is coupled to the read data lines, indicating the contents of the selected memory cell. The sense amplifier provides a differential current onto a corresponding read global data line pair in response to the differential voltage.

Abstract: A BICMOS bit line load for a memory includes first and second bipolar transistors having emitters respectively coupled to first and second bit lines of a differential bit line pair. Collectors of the first and second bipolar transistors receive a reference voltage. An equalization signal is applied to bases of the first and second bipolar transistors. The equalization signal is at a logic low voltage during a write cycle, and at a logic high voltage otherwise. In order to decrease the worst-case reverse bias, which causes bipolar transistors to degrade over time, a difference between the logic high voltage and the logic low voltage of the equalization signal is limited to a predetermined voltage.

Abstract: A low di/dt BiCMOS output buffer with improved speed for a device such as a memory includes an input portion, a level shifter, first and second logic portions, and an output stage. The input portion provides first and second signals respectively in response to positive and negative differences between true and complementary input signals. The level shifter decreases the first and second signals by a predetermined amount to provide third and fourth signals. When selected, the first and second logic portions provide a pullup signal and a pulldown signal respectively in response to the third and fourth signals to the output stage. The output stage provdes a data output signal at a logic high voltage in response to the pullup signal and at a logic low voltage in response to the pulldown signal.

Abstract: A BiCMOS (Bipolar Complementary Metal Oxide Semiconductor) bit line load for a memory with improved speed write recovery and improved reliability. Comprises a first bipolar transistor, a resistor, and a second and third bipolar transistors respectively coupled to first and second bit lines of a differential bit line pair. The improvement in speed is accomplished through the use of the bipolar transistors which generally switch faster than corresponding MOS transistors. The first bipolar transistor has a collector coupled to a power supply voltage terminal, a base for receiving a bias signal, and an emitter coupled to the collectors of the second and third bipolar transistors. The resistor is coupled between the collector and emitter of the first bipolar transistor. The bit line load has improved reliability by preventing self-boosting at the bases of the second and third bipolar transistors by decreasing their collector voltages enough during switching to bias them into saturation.

Abstract: An output buffer for a device such as a memory comprises a voltage regulator, a current source portion, a switching portion, and an output portion. The voltage regulator provides a constant voltage independent of fluctuations between first and second power supply voltages. The current source portion provides first and second currents to first and second nodes to limit the rate at which transistors in the output portion become conductive. The switching portion provides voltage signals on the first and second nodes respectively in response to positive and negative voltage differences between first and second input voltages. The output portion provides an output signal at either a logic high or a logic low voltage respectively in resonse to the voltage signals at the first and second nodes. The current source portion allows the use of faster bipolar transistors to improve the speed of the output buffer while maintaining accepable di/dt.

Abstract: A BiCMOS logic circuit with self-boosting immunity comprises a resistor, first and second transistors, a switching portion, and a discharge portion. The resistor and first transistor bias the switching portion to first and second reference voltages, which may be equal. The second transistor is a bipolar transistor providing an output signal to a load. The switching portion couples the bias voltage provided by the resistor and the first transistor to the base of the second transistor in response to a true result of a logic operation on at least one input signal and couples the base of the second transistor to a second power supply voltage terminal in response to a false result of the logic operation. The discharge portion couples the output signal to a logic low or pulldown voltage in response to a false result of the logic operation. In one form, the logic operation is a logical inversion of an input signal.

Abstract: A memory which senses output signals from a selected memory cell during a read cycle using a non-address transition detection apparatus. The memory has a plurality of memory cells which provide signals to a pair of bit lines when selected. An input circuit drives word lines and select a bit line pair of a memory cell located at the intersection of a selected word line and a selected bit line pair. The memory cell outputs bit line signals which are sensed by a combination of a differential amplifier, a level shifter, and a transconductance amplifier, and are thereafter output and presented externally at a logic state representative of a differential current at outputs of the transconductance amplifier. The combination sensing apparatus and a method for constructing such an apparatus decrease access time significantly over a prior art memory using address transition detection.

Abstract: A memory which contains a global data line pair and a plurality of loads for the global data line pair distributed thereon. The global data lines run the length of the memory, and are connected to a set of arrays distributed along the global data lines, of which each array provides a voltage on the global data lines when selected. The first load is located above the first array and the last is located below the last array. Other global data line loads are placed between consecutive arrays. In a read mode of operation a pair of loads associated with each array is enabled when a corresponding array is selected. Placement of the loads in this manner decreases an access time considerably.

Abstract: In integrated circuits which include both ECL and CMOS circuits, there is an ECL to CMOS translator which converts ECL logic levels to CMOS logic levels. To convert from ECL to CMOS levels, the ECL logic high is coupled to the base of an NPN transistor which provides a CMOS logic low. The ECL logic low is prevented from being coupled to the base of the NPN transistor. The CMOS logic high is obtained by an analogous second circuit which is responsive to a complementary ECL signal the output of which is coupled to a P channel transistor. The P channel transistor either provides the CMOS logic high output or is non-conductive.