Abstract: A Flash memory sense amplifier precharge device having a self-bias circuit and a precharge circuit. The self-bias circuit is coupled to precharge a data node in response to a first control signal. The precharge circuit is coupled to precharge the data node in response to a second control signal, wherein the precharge circuit aids the self-bias circuit precharge the data node faster than the self-bias circuit could itself.

Abstract: A sense amplifier for sensing an input voltage level of a data signal. Such a sense amplifier pre-charges, and subsequently discharges, a pair of nodes through a respective pair of discharge paths. Each of those discharge paths is capable of performing the discharge operation at a rate that is related to either a system voltage supply or an input logic level of the data signal. Because the discharge path that is associated with the data signal includes a greater amount of conductance, it can perform the discharge operation at a faster rate, even where the input logic level does not exceed the voltage of the system voltage supply. A determination is made as to which of the discharge is the faster and, responsively, a rail-to-rail output signal having the same polarity as the data signal, is generated.

Abstract: A circuit configured to correct a duty cycle error or vary the duty cycle of a clock signal. The circuit includes a differential amplifier or control circuit that receives differential signal inputs. At least one differential pair of transistors is connected to outputs of the differential amplifier or control circuit. Outputs of the one or more differential pairs of transistors are connected to inputs of a differential circuit. The differential amplifier or control circuit is connected to the outputs of the differential circuit. The one or more differential pairs of transistors is configured to change a DC level of at least one of the inputs of the differential circuit in order to shift a cross over point of the inputs of the differential circuit and thereby effect a duty cycle change (or correction) at the outputs of the differential circuit.

Abstract: A receiver is provided which quickly and efficiently recognizes signals by including with the receiver a resolving circuit which is coupled to a signal generation circuit which provides a differential current. The resolving circuit is coupled to a latching circuit. The resolving circuit can operate with supply voltage levels as low as one threshold voltage. Also, the signal setup and hold times are inherently vary small due to the high intrinsic bandwidth of the receiver. Other advantages include reduced power consumption, high speed operation, good rejection of input noise and power supply noise, ability to resolve small (e.g., 1.0 mVolt) voltage differences, reduced capacitive loading, and the ability to function with a variety of types of drivers, including HSTL, DTL and PECL.

Abstract: To reduce current consumption in a sense amplifier circuit in a semiconductor integrated-circuit device, in particular, in a semiconductor integrated-circuit having a non-volatile memory as a memory element thereof. A Switching element for cutting off a direct current at the end of data reading from a memory is arranged in a path through which the direct current flows. In this way, the switching element cuts off the direct current at the moment of completion of the data reading from the memory, thereby substantially reducing current consumption.

Abstract: A differential receiver circuit includes: a current source 20; a differential pair 22 and 24 coupled to the current source 20; a first transistor 26 coupled to a first branch of the differential pair 22 and 24; a second transistor 28 coupled to a second branch of the differential pair 22 and 24, the first and second transistors 26 and 28 are cross coupled; a third transistor 54 coupled in series with the first transistor 26; a fourth transistor 56 coupled in series with the second transistor 28; a fifth transistor 30 coupled in parallel with the first and third transistors 26 and 54; and a sixth transistor 32 coupled in parallel with the second and fourth transistors 28 and 56.

Abstract: An amplifier in a semiconductor integrated circuit includes a current-mirror typed differential amplifier and a cross-coupled differential amplifier, whereby a minute voltage difference from a bit line signal or a data bus signal is amplified. The amplifier for generating an amplified signal includes a load for coupling to a first voltage potential, a first sense amplifier responsive to a first data signal, and a second sense amplifier responsive to a second data signal. The first and second sense amplifiers are commonly coupled to the load, and the amplified signal of the first or second data signal is generated.

Abstract: A sense amplifier having dual differential inputs configured to accept differential analog input voltages. The differential analog input voltages are fused to determine a weighted signal digitally representative of the differential analog input voltages. An input offset voltage cancellation circuit may be coupled to the sense amplifier to reduce an input offset voltage of the sense amplifier.

Abstract: An integrated differential buffer circuit and its method of operation are described in which the buffer circuit has an internal bias line for controlling the supply of voltage to the buffer circuit. When the buffer circuit is first enabled, a start voltage is initially applied to the bias line and then removed to ensure proper operation of the buffer circuit when first enabled.

Abstract: Method and device for reducing the time constant of a system having a conductor connected thereto by connecting an impedance between the conductor and a potential as the voltage on said conductor exceeds a preselected value.

Abstract: An integrated circuit interconnection comprising a transmission line having a low characteristic impedance, and including a first end and a second end. A driver is coupled to the first end of the transmission line, and the transmission line is terminated with a current sense amplifier having an input impedance corresponding to the characteristic impedance of the transmission line. A plurality of components selected from the group consisting of capacitive elements, inductive elements and a combination of capacitive and inductive elements are connected at spaced intervals to the transmission line between the first and second ends.

Abstract: An output circuit is driven by a first differential amplification circuit having an N-channel differential amplification stage that compares a reference voltage VREF with an input signal IN, and a second differential amplification circuit having a P-channel differential stage. An output of the first differential amplification circuit is given as the gate voltage of P-channel MOS transistors in the output circuit, and an output of the second differential amplification circuit is given as the gate voltage of N-channel MOS transistors in the output circuit. This realizes an input buffer with reduced error operations even under threshold voltage variations caused by process variations and others.

Abstract: A circuit that senses changes in the electrical characteristics of a guard ring, and generates one or more signals based, at least in part, on the electrical characteristics that are sensed, is incorporated into an integrated circuit The one or more signals generated by the circuit are indicative of the reliability of the integrated circuit. In one embodiment of the present invention, a first point of the guard ring is electrically coupled to a voltage supply node by a switchable element such as a MOSFET, and at least two points of the guard ring are electrically coupled respectively to two input terminals of a differential amplifier circuit in such a way that voltage changes across the guard ring can be sensed.

Abstract: The device for the comparison of the levels of two input signals MI, PI includes a first comparator COMP1, the switching of the comparator being expressed by a change-over of the output OUT1 of the comparator from a first logic state into a second logic state, the change-over of the output OUT1 from one logic state “0” into the other state “1” being faster than the change-over in the other direction. The device also includes a second comparator COMP2 with an identical structure, to whose input the signals to be compared are applied invertedly so that the switching operations in the comparators are inverted. The output of each comparator is applied to an associated logic circuit 1, 2 capable of accelerating the inverse switching in the other comparator for a change in the output corresponding to the fastest change-over.

Abstract: A data transfer arrangement. The data transfer arrangement includes two active pull up/active pull down bus drivers and a voltage precharge source. A differential bus is coupled to the bus drivers and to the voltage precharge source. A latching sense amplifier is coupled to the differential bus and serves as the bus receiver. The bus drivers operate in a precharge phase and a data transfer phase. The bus receiver operates in an analogous but opposite manner, i.e., when the bus drivers are in the precharge phase, the bus receiver is in the data transfer phase and when the bus drivers are in the data transfer phase, the bus receiver is in a precharge phase.

Abstract: Disclosed herein is a sense amplifier for use in a semiconductor memory device. The sense amplifier of the present invention is comprised of a reference voltage generator, a sense voltage generator, and an inverter. The reference voltage generator produces a reference voltage at a reference node, and the sense voltage generator produces a sense voltage at a sense node in response to an on or off state of a memory cell. In addition, the inverter is coupled to the sense node, for detecting whether the sense voltage is higher than a predetermined trip voltage of the inverter, and for outputting a logic low or high signal representation of the on or off state of the memory cell. The sense amplifier of the present invention secures a stable, speedy sensing operation despite increases in degree of integration and decreases in power supply voltages, thereby to increase the operational speed of the device.

Abstract: An amplifier in a semiconductor integrated circuit includes a current-mirror typed differential amplifier and a cross-coupled differential amplifier, whereby a minute voltage difference from a bit line signal or a data bus signal is amplified. The amplifier for generating an amplified signal includes a load for coupling to a first voltage potential, a first sense amplifier responsive to a first data signal, and a second sense amplifier responsive to a second data signal. The first and second sense amplifiers are commonly coupled to the load, and the amplified signal of the first or second data signal is generated.

Abstract: A digital differential receiver IC that rejects the inter-symbol interference (ISI) that is imposed upon differential digital signals when long runs of a digital state (0 or 1) are transmitted over long cables. The ISI-rejecting differential receiver IC is implemented in either bipolar technology (n-p-n or p-n-p) or in insulated gate FET technology (p-channel or n-channel). The primary differential pair of transistors is connected to a secondary differential pair of transistors through a filter network so that a high pass “shelf” filter transfer function exists between the differential input signals and the output signals. This transfer function mitigates ISI by reducing the gain for long runs of a digital state (low frequencies) and enhancing the gain for the state transition edges (high frequencies).

Abstract: A power on reset (POR) circuit in a semiconductor device which is process independent and resistant to noise present in a power supply voltage when the power supply voltage has not yet obtained a predetermined operational voltage level. The POR circuit includes a differential amplifier, a non-inverting input control circuit and an inverting input control circuit. The differential amplifier senses and amplifies a difference in voltage between the non-inverting input terminal and the inverting input terminal. The non-inverting input control circuit controls a voltage of the non-inverting input terminal of the differential amplifier. The inverting input control circuit controls a voltage of the inverting input terminal of the differential amplifier.

Abstract: Various circuit techniques for implementing ultra high speed circuits use current-controlled CMOS (C3MOS) logic with inductive broadbanding fabricated in conventional CMOS process technology. Optimum balance between power consumption and speed for each circuit application is achieve by combining high speed C3MOS logic with inductive broadbanding/C3MOS logic with low power conventional CMOS logic. The combined C3MOS logic with inductive broadbanding/C3MOS/CMOS logic allows greater integration of circuits such as high speed transceivers used in fiber optic communication systems.

Abstract: A sense amplifier circuit including a current difference amplification circuit and a voltage difference amplification circuit, and a precharge circuit for precharging digit lines, are provided between the digit lines. A memory cell including one transistor and one capacitor is connected to the digit line. The voltage difference amplification circuit includes an n-channel flip flop and a p-channel flip flop, and is provided with nodes. The nodes are connected to the digit lines via a sense amplifier connection circuit.

Abstract: A sense amplifier includes a pair of differential input terminals and a pair of differential output terminals. Each of a pair of precharge circuits connects a respective one of the differential output terminals to precharge potential and has a clocking input. The precharge circuits maintains the respective differential output terminals at ground in response to a precharge state of a signal at the clocking input. The sense amplifier also may include a pair of evaluation circuits, each connecting a respective one of the differential output terminals to an evaluation potential and coupled to a respective one of the differential input terminals. The evaluation circuits may transition the respective output terminal to an evaluation voltage in response to an evaluation state of a signal at the respective differential input terminal.

Abstract: A semiconductor integrated circuit includes a sense amplifier for amplifying an input signal and an complementary input signal, a full differential amplifier for amplifying the output of the sense amplifier, and a latch for latching the output of the full differential amplifier and outputting the latched output.

Abstract: A current sense amplifier circuit using a dummy bit line is provided. The current sense amplifier circuit includes a cell current generator, a reference current generator, and a sense amplifier. The cell current generator includes a memory cell connected to a word line and a bit line and generates memory cell current applied to the memory cell and bit line charge current for charging the bit line. The reference current generator includes a dummy bit line and a reference cell and generates reference cell current applied to the reference cell and dummy bit line charge current for charging the dummy bit line. The sense amplifier includes a first input terminal, connected to the cell current generator, for receiving the memory cell current and the bit line charge current and a second input terminal, connected to the reference current generator, for receiving the reference cell current and the dummy bit line charge current.

Abstract: A clock circuit on an integrated circuit chip includes a driver having an output for deriving an output clock wave responsive to a clock wave of a clock wave source, a clock line having a first end coupled to the output of the driver, and a receiver having an input coupled to a second end of the clock line. The receiver has a resistive input impedance causing the clock line carrying the output clock wave to the input of the receiver to present to the driver output an impedance having a resistance-capacitance time constant that is a relatively small fraction of a period of the clock wave.

Abstract: A low-voltage differential dual receiver for a SCSI bus uses a symmetrical driver by doing without a termination bias voltage. The data phase and protocol phase of SCSI communication are separated by using two receivers and optimizing each receiver for its particular function. A high-speed receiver is used when transmitting data at high-speeds, and a lower performance, low-speed receiver is used for other SCSI phases. A built-in offset allows the low-speed receiver to operate correctly during bus arbitration. The built-in offset in the low-speed receiver takes the place of the termination bias voltage in a traditional SCSI bus and is implemented in a variety of ways. In a first example, an N-well generation circuit produces a bulk voltage for one transistor of the differential transistor pair that is different than a supply voltage supplied to the bulk of the other transistor.

Abstract: A differential comparator is disclosed including first and second input amplifier circuits. The input amplifier circuits have respective signal input terminals for receiving respective first and second complementary input signals and respective output terminals. The first and second input amplifier circuits cooperate to produce a difference signal. Reference signal circuitry is coupled to the input amplifier circuits and is operative to produce a predetermined reference signal for comparison to the difference signal. The input amplifier circuits and the reference signal circuitry cooperate to define a single stage.

Abstract: An embodiment of the invention is directed to a metal oxide semiconductor field effect transistor (MOSFET) comparator, which includes a differential amplifier having first and second inputs and first and second outputs. A first offset storage device is connected to the first input at one end and receives a first input signal of the comparator at another end. A second offset storage device is connected to the second input at one end and receives the first input signal during an autozero time interval and a second input signal of the comparator thereafter. During the autozero time interval, offset voltages are stored. Thereafter, the offsets are cancelled when the input signals are applied to their respective storage device. In a particular embodiment of the invention, the amplifier features a dual purpose load that causes the amplifier to first preamplify and then regeneratively drives the outputs.

Abstract: An inventive sense amplifier in a memory device includes a feedback-controlled differential amplifier with a pair of differential output terminals, one of which is driven to ground and the other of which is driven to the supply voltage VCC when a logic “1” or “0” bit is sensed by the sense amplifier. Pre-charge circuitry pre-charges the output terminals of the differential amplifier to the supply voltage VCC before a logic bit is sensed so little or no time is wasted pulling one of the terminals up to the supply voltage VCC when a logic bit is sensed. Tri-state output circuitry connected to the differential amplifier outputs a sensed logic bit to an internal data bus of the memory device, and the tri-state nature of the output circuitry allows the circuitry to present a high impedance to the internal data bus. As a result, the sense amplifier can share the internal data bus with other sense amplifiers without interfering with the operation of the other sense amplifiers.

Abstract: A programmable voltage divider has normal and test modes of operation. The divider includes first and second supply nodes, a divider node that provides a data value, and a first divider element that is coupled between the first supply node and the divider node. The divider also includes a controlled node, a second divider element that has a selectable resistivity and that is coupled between the divider node and the controlled node, and a test circuit that is coupled between the controlled node and the second supply node. During the normal mode of operation, the first and second divider elements generate the data value having a first logic level when the second divider element has a first resistivity, and generate the data value having a second logic level when the second divider element has a second resistivity. The test circuit generates a first voltage at the controlled node during the normal mode of operation, and generates a second voltage at the controlled node during the test mode of operation.

Abstract: A semiconductor integrated circuit device for a magnetic disk apparatus has analog circuits such as a read/write circuit and digital circuits such as an interface driver circuit, a control circuit, and a stepping motor driver circuit, all of these circuits operating on a single supply voltage. The semiconductor integrated circuit device further has a voltage regulator whose output voltage is lower than the supply voltage and variable according to the voltage applied to an output voltage adjustment terminal. The control circuit operates on the output voltage of this regulator.

Abstract: In an high-frequency LSI chip, a clock signal generating circuit establishes accurate synchronization between an input clock signal and an internal clock signal to prevent an input circuit from causing a synchronization shift. The clock signal generating circuit includes an input circuit for amplifying an input signal and outputting an amplified signal as a first internal signal; a variable delay circuit, on the basis of a control signal, for delaying the first internal signal and outputting a delayed signal as a second internal signal; a phase comparator for finding a phase difference between the input signal and second internal signal and outputting a phase difference signal indicative of the phase difference; and a control circuit for generating the control signal on the basis of the phase difference signal. Thus, the influences of a delay caused by the input circuit, which would not be avoided in the prior art, can be avoided and the accurate internal clock signal can be generated.

Abstract: A latch type sense amplifier circuit comprises first and second latch circuits which output the same output signals when a potential difference between a bit line pair is equal to or greater than a predetermined value. The first and second latch circuits output different output signals when the potential difference between the bit line pair is less than the predetermined value. The latch type sense amplifier circuit further comprises a comparison result signal generating circuit which compares the output signals from the first and second latch circuits and outputs a signal indicative of the comparison result.

Abstract: A CMOS-based circuit for translating a differential-input into a single-ended output capable of driving large loads with little or no compromise in speed. This translator provides a symmetric single-ended output signal capable of driving a wide range of loads with minimal distortion. In contrast to earlier such translators, the circuit of the present invention ensures that the output signal is coupled directly to the high-voltage rail after being switched to logic HIGH and that that coupling remains in effect until an input signal causing the output to switch to logic LOW is received. Similarly, when the output signal is switched to logic LOW, it is coupled directly to the low-voltage rail of the circuit and left so coupled until it is affirmatively switched to logic HIGH. This feature ensures that regardless of load, the output signal completely switches to the proper logic stage.

Abstract: A dynamic logic circuit where a duality logic tree is connected to a sense amplifier through a switch, which reduces the power consumption and suppresses coupling noise by controlling the connection of the logic tree and the sense amplifier by the voltages of the input and output nodes of the sense amplifier.

Abstract: A sense amplifier includes a voltage supply terminal, first and second differential bit line inputs and a differential amplifier. The differential amplifier has first and second amplifier inputs, which are coupled to the first and second differential bit line inputs, respectively, and has an amplifier output. A first transistor is coupled between the voltage supply terminal and the first bit line input and has a current control terminal coupled to the second bit line input. A second transistor is coupled between the voltage supply terminal and the second bit line input and has a current control terminal coupled to the first bit line input.

Abstract: A silicon-on-insulator (SOI) complementary metal oxide semiconductor (CMOS) sense amplifier is provided with improved matching characteristics and sense point tolerance under no penalty of performance degradation. The sense amplifier includes a silicon-on-insulator (SOI) field effect transistor. A flooding field effect transistor is coupled to a body of the silicon-on-insulator (SOI) field effect transistor. The flooding field effect transistor is activated before the sense amplifier is set. The flooding field effect transistor has an opposite polarity of the silicon-on-insulator (SOI) field effect transistor. The flooding field effect transistor provides a charging path to a voltage supply rail. A pair of flooding field effect transistors serve as charging to voltage supply rail elements for silicon-on-insulator (SOI) field effect transistors on each side of complementary bitline structures of the sense amplifier.

Abstract: An integrated circuit operational amplifier (op amp) is protected from input voltage levels which may cause output phase reversal of the op amp. Voltage comparators monitor the input voltages to the op amp differential input transistor pair. The op amp and comparators may be fabricated on an integrated circuit substrate and packaged in an integrated circuit package. When the input voltage is of such a value which may cause output phase reversal, a comparator senses same and is coupled to circuits within the op amp which prevent the op amp output voltage from going into phase reversal.

Abstract: In a sense amp/latch, the reset/sense phase of the sense amp/latch is separated into two separately controllable operations. By separating the reset/sense phase into two separately controllable operations, the parameters associated with optimization (speed and/or completeness of reset vs. larger gain during sensing) are substantially independent of each other and therefore do not conflict with each other. The separation of the reset/sense phase into two separately controllable operations is accomplished by setting a load impedance of the sense amp/latch to a first level during a reset phase, to a second level during a sensing phase, and to a third level during a latching phase.

Abstract: An input buffer circuit for receiving digital data signals from a transmission line includes a monitor section for monitoring data signals at the input of the buffer circuit. A power control section receives a control signal from the monitor section depending on whether the data is detected at the input of the input buffer circuit. The power control section can switch the input buffer into a low power standby mode or into an operating mode depending on whether a data signal transmitted via the transmission line is available at the input of the monitor section.

Abstract: A static, low-power differential sense amplifier (DSA) and method includes operation of cross-linked channels having complementary differential nodes separated from ground by corresponding parallel-transistor pairs. The DSA output channels have complementary output nodes separated from ground by corresponding parallel-transistor pairs. The DSA further includes logic gates to produce a sense amplifier output. Each logic gate is driven by a corresponding complementary differential node and an opposite complimentary output node. The DSA includes transistors activating a done line under control of the complementary differential nodes.

Abstract: A sense amplifier includes cross-coupled n-transistors that provide, from a predetermined time during one sample period to the start of the next precharge period, a path from a discharging internal node to the low supply voltage VSS. The n-transistors provide a discharge path from the time the internal node falls sufficiently below a precharge voltage to cause the transistors to operate differentially, until the time the node is again precharged, regardless of changes in the state of the input signals. The gate voltages of the cross-coupled transistors are controlled by the internal nodes, and the transistors participate in a positive feedback loop that drives the non-discharging internal node to a high supply voltage VDD through a cross-coupled p-transistor that is controlled by the discharging node.

Abstract: An amplifier is provided that includes a current amplifying and current/voltage converting part that performs current amplification with respect to signals received from a first data bus and a second data bus. The current amplifying and current/voltage converting part further converts the amplified signal currents into a voltage. The amplifier further includes a voltage amplifying part that amplifies the voltage from the current amplifying part and current/voltage converting part to produce an amplified output.

Abstract: The present invention provides a limiter amplifier using a differential pair of MOS transistors in an input stage. A plurality of MOS transistors each having a drain and a gate connected to each other as a load transistor, are connected in series to the drains of the differential pair of MOS transistors in the input stage. MOS transistors are current-mirror-connected to the load transistors to perform feedback on the differential pair of MOS transistors in the input stage. The outputs of the differential pair of MOS transistors in the input stage are amplified by another differential pair of MOS transistors in an output stage.

Abstract: The present invention provides a sense amplifier that incorporates a logic function. Specifically, that logic function is incorporated into the sense amplifier such that the propagation time of the logic function is avoided and the effective data set-up time of the sense amplifier is reduced. The sense amplifier includes a pair of discharge paths having a true or a complementary version of the logic function associated therewith. When the true or complementary version of the logic function is asserted, one of the discharge paths is turned-on. The output signal that is associated with that discharge path is discharged to a logic low level and the other output signal is pulled to a logic high level. Accordingly, the resulting logic level of the logic function is generated and latched using only the sense amplifier circuit.

Abstract: A circuit for use in comparing input voltages includes switching elements initially configured in a reset mode to minimize charge or current conduction before entering a comparison mode. A strobe signal reconfigures the switching elements to transition from the reset mode to the comparison mode. Finally, a determination is made as to which of the input voltages is larger or smaller.

Abstract: A sensor for measuring a current passing through a load. The sensor has a power transistor having a first terminal connected to substantially constant voltage and a second terminal connected to the load. The sensor can sample a voltage difference with a variable capacitor, and a controller can be configured to cause a variable capacitor in the current sensor to have a capacitance inversely proportional to a resistance of the power transistor, whereby a charge stored on the variable capacitor is proportional to the current passing through the power transistor when the sampling switches are opened. A comparator can compare the current through the power transistor to a known reference current to generate a digital output signal. The sensor can include a power transistor, reference transistor and amplifier connected and configured so as to generate a signal on a reference line having a current of known proportion to the current passing through the load.

Abstract: In an amplifier having an input terminal to which input data is supplied and an output terminal from which output data corresponding to the input data is output, the input and output terminals are disposed between a power supply node to which a power supply is applied and a reference voltage node to which a reference voltage is applied. The output terminal and the reference voltage node are connected to each other and the input terminal and the output terminal are disconnected from each other, before the input data is supplied to the input terminal. The output terminal and the reference voltage node are disconnected from each other and the input terminal and the output terminal are connected to each other, after the input data is supplied to the input terminal.

Abstract: A semiconductor integrated circuit including an input circuit constituted as a single-input differential circuit which has a first MOSFET to whose gate a reception signal with a small amplitude with respect to a power supply voltage is supplied and a second MOSFET to whose gate a reference voltage corresponding to an intermediate value of the reception signal is supplied. A dummy circuit is provided and transmits substantially the same power supply noise as the power supply noise transmitted to the gate of the first MOSFET through a electrostatic protection circuit provided to an external terminal which receives the reception signal.

Abstract: A method of processing data having one of four voltage levels stored in a DRAM cell is comprised of sensing whether or not the data voltage is above or below a voltage level midway between a highest and a lowest of the four levels, setting the voltage on a reference line higher than the lowest and lower than the next highest of the four levels in the event the data voltage is below the midway voltage level, and setting the voltage on the reference line higher than the second highest and lower than the highest of the four levels in the event the data voltage is above the midway point, and sensing whether the data voltage is higher or lower than the reference line, whereby which of the four levels the data occupies is read.