KR100904466B1 - Termination circuit of On Die Termination Device - Google Patents

Abstract

The present invention relates to an on die termination device capable of compensating a mismatch between a calibration circuit and a termination circuit. The calibration circuit of the on die termination device according to the present invention includes a pull-up calibration code for each pull-up termination drive. And pull-up parallel resistors that pull up and drive the input / output node while being turned on and off, wherein at least one of the pull-up parallel resistors controls the amount of current flowing through the pull-up control signal at turn-on. Pull-up termination resistors; And pull-down parallel resistors that pull-down drive the input / output node while the pull-down termination is driven in response to pull-down calibration codes, wherein at least one of the pull-down parallel resistors is turned on by a pull-down control signal. It includes a pull-down termination resistor portion, characterized in that the amount of current flowing through it.

On Die Termination, Calibration, Output Driver

Description

Termination Circuit of On Die Termination Device

The present invention relates to a technique for ensuring that the termination circuit of an on die termination device, such as the termination resistor of an output driver or input buffer, has the correct target resistance value and IV curve.

Various semiconductor devices implemented as integrated circuit chips, such as CPUs, memories and gate arrays, are incorporated into various electrical products such as personal computers, servers or workstations. In most cases, the semiconductor device has a receiving circuit for receiving various signals transmitted from the outside world through an input pad and an output circuit for providing an internal signal to the outside through an output pad.

Meanwhile, as the operating speed of an electrical product is increased, the swing width of a signal interfaced between the semiconductor devices is gradually reduced. The reason is to minimize the delay time for signal transmission. However, as the swing width of the signal decreases, the influence on external noise increases, and the reflection of the signal due to impedance mismatching (also referred to as mismatch) at the interface stage becomes more severe. The impedance mismatch occurs due to external noise, fluctuations in power supply voltage, change in operating temperature, change in manufacturing process, or the like. When impedance mismatching occurs, high-speed data transfer is difficult and output data output from the data output terminal of the semiconductor device may be distorted. Therefore, when the semiconductor device on the receiving side receives the distorted output signal to the input terminal, problems such as setup / hold fail or input level determination error may occur frequently.

In particular, a memory device requiring high speed of operation employs an impedance matching circuit called on die termination in the vicinity of a pad in an integrated circuit chip to solve the above problems. In general, in an on die termination scheme, source termination is performed by an output circuit on the transmission side, and parallel termination is performed by a termination circuit connected in parallel to a receiving circuit connected to the input pad on the receiving side.

ZQ calibration refers to the process of generating pull-up and pull-down calibration codes that change as PVT (Process, Voltage, Temperature) conditions change, which is generated as a result of ZQ calibration. The above codes are used to adjust the resistance value of the on-die termination device (the termination resistance value on the DQ pad side in the case of a memory device). (Calibration is performed using the ZQ node, which is a node for calibration.) It is called ZQ calibration because it loses.)

Hereinafter, the ZQ calibration performed in the on die termination device will be described.

1 is a configuration diagram of a portion (calibration circuit) for performing a ZQ calibration operation in a conventional on-die termination device.

As shown in the figure, the conventional on-die termination device is a pull-up calibration resistor 110, a dummy calibration resistor 120, a pull-down calibration resistor 30, a reference voltage generator 102, Comparators 103 and 104 and counters 105 and 106 are included to perform a ZQ calibration operation. The pull-up calibration resistor unit 110 is configured to include a plurality of pull-up resistors that are turned on / off by receiving the pull-up calibration codes PCODE <0: N>. In addition, the dummy calibration resistor 120 is configured in the same manner as the pull-up calibration resistor 110, and the pull-down calibration resistor 130 receives the pull-down calibration code NCODE <0: N>. It consists of a number of pull-down resistors that receive inputs on and off.

The pull-up calibration resistor unit 110 is used to generate a primary calibration code (PCODE <0: N>) while calibrating with an external resistor 101 connected to a ZQ node, and a dummy calibration resistor. The unit 120 and the pull-down calibration resistor unit 130 may use a second calibration code (PCODE <0: N>) generated using the pull-up calibration resistor unit 110. To generate NCODE <0: N>).

In operation, the comparator 103 is a ZQ generated by connecting an external resistor 101 (typically 240?) Connected to a ZQ pin (outside the chip of the ZQ node) and the pull-up calibration resistor 110. The voltage of the node is compared with the reference voltage generated by the internal reference voltage generator 102 (generally set to VDDQ / 2) to generate an UP / DOWN signal.

The counter 105 receives the up / down signal UP / DOWN to generate a binary code PCODE <0: N>. The counter 105 generates a pull-up calibration resistor with the generated binary code PCODE <0: N>. Adjust the resistance value by turning on / off the resistors connected in parallel in 110). The resistance value of the adjusted pull-up calibration resistor unit 110 again affects the voltage of the ZQ node and the operation as described above is repeated. That is, the pull-up calibration resistor circuit 110 is calibrated so that the total resistance value of the pull-up calibration resistor circuit 110 is equal to the resistance value of the external resistor 101 (typically 240?). (Pull-Up Calibration)

The binary code (PCODE <0: N>, pull-up calibration code) generated during the above-described pull-up calibration process is input to the dummy calibration resistor 120 and the entire dummy calibration resistor 120 The resistance value is determined (finally the dummy calibration resistor circuit has the same resistance value as the pull-up calibration resistor circuit). The pull-down calibration operation now begins, similar to the pull-up calibration, using the comparator 104 and the counter 106 so that the voltage at node a equals the reference voltage (VREF), that is, the pull-down calibration resistor. The total resistance value of the unit 130 is calibrated to be equal to the total resistance value of the dummy calibration resistance unit 120 (pull-down calibration).

The binary codes PCODE <0: N> and NCODE <0: N> generated as a result of the above-described ZQ calibration (pull-up and pull-down calibration) are the pull-up and pull-down of the calibration circuit of FIG. The resistance value of the die termination device input to the pull-up and pull-down resistors (termination resistors) on the input / output pad side laid out in the same manner as the calibration resistors 110 and 130 is determined. The pullup and pulldown termination resistors on the DQ pad side.

2 is a diagram illustrating an output driver (termination circuit of an on die termination device) of a semiconductor memory device using calibration codes PCODE <0: N> and NCODE <0: N> generated by the calibration circuit of FIG. 1. It is a figure which shows the determination of termination resistance value.

The output driver outputs data from the semiconductor memory device, and as shown in the figure, pre-drivers 210 and 220 provided for up / down and pull-up termination resistors for outputting data ( 230 and a pull-down termination resistor 240.

In brief, the pre-drivers 210 and 220 provided in the up / down control the pull-up termination resistor 230 and the pull-down termination resistor 240, respectively. When the resistor unit 230 is turned on to make the data pin DQ high, and the output low data, the pull-down termination resistor 240 is turned on to bring the data pin DQ low. Make. In other words, the data pin DQ is terminated by pull-up or pull-down to output 'high' or 'low' data.

At this time, the number of resistors in the pull-up termination resistor 230 and the pull-down termination resistor 240 that are turned on is the pull-up calibration code (PCODE <0: N>) and the pull-down calibration code (NCODE <0: N>). Determined by That is, whether the pull-up termination resistor 230 is turned on or the pull-down termination resistor 240 is turned on depends on the logic state of the output data, but each resistor in the turned-on termination resistor 230 or 240 is turned on. The on / off of is determined by the calibration codes PCODE <0: N> and NCODE <0: N>.

For reference, the resistance value target values of the pull-up termination resistor 230 and the pull-down termination resistor 230 must be equal to the resistance values 240Ω of the calibration resistors 110, 120, and 130 of FIG. 1. It is not the same, but it can have values such as 120Ω, 60Ω, which is 1/2, 1/4 of 240Ω, and the termination resistance part 230, 120, 60Ω for 240, 120, 60Ω because the termination resistance value may vary depending on the applied system. It is also possible to adopt the method of having all of them) and using them selectively.

DQp_CTRL and DQn_CTRL input to the predrivers 210 and 220 of the drawing represent a group of control signals input to the predrivers 210 and 220.

In the case where the termination circuit of the on-die termination device is the output driver (Fig. 2) of the semiconductor memory device, the termination circuit is terminated by the pull-up termination resistor 230 and the pull-down termination because the input / output node DQ is terminated by pull-up and pull-down. Although all resistors 240 are provided, the termination circuit may include only pull-up termination resistors 230 or only pull-down termination resistors 240.

For example, in the case of a GDDR semiconductor memory device, when data is input from the outside, the data is input while the input / output node DQ is terminated only by the pull-up. Accordingly, the termination circuit of the on-die termination device may include only the pull-up termination resistor 230 or the pull-down termination resistor 240 according to the definition of the input / output interface.

In the calibration operation of the on-die termination device, the calibration resistors 110 and 130 of the calibration circuit (FIG. 1) and the termination resistors 230 and 240 of the termination circuit (FIG. 2) are configured in the same manner. Similarly, it is proposed under the assumption that it is affected by PVT. In practice, however, the configuration of the ZQ pad side of the calibration circuit (FIG. 1) and the configuration of the DQ pad side with the termination circuit (FIG. 2) cannot be exactly the same.

For example, in the calibration circuit (FIG. 1), the pull-up calibration resistor 110 is located at the ZQ node and the pull-down calibration resistor 130 is located at the A node, while the termination circuit (FIG. 2) is used. The pull-up termination resistor 230 and the pull-down termination resistor 240 of both are connected to the DQ pad, but inevitably bring a difference in the configuration, and because the target resistance value may also be different from the calibration circuit (FIG. 1). ) And a certain mismatch always exists between the termination circuit (FIG. 2).

Therefore, even after the calibration operation is performed, there is a problem that a mismatch occurs in which the termination resistance value of the termination circuit falls short of or exceeds the original target.

An object of the present invention is to reduce the mismatch occurring between the calibration circuit and the termination circuit of the on-die termination device and to adjust the termination strength in the termination circuit.

The termination circuit of the on-die termination device according to an embodiment of the present invention includes pull-up parallel resistors that pull up and drive an input / output node while being turned on and off in response to each pull-up calibration code during pull-up termination driving. At least one of the pull-up parallel resistors are pull-up termination resistors characterized in that the strength of the turn-on is controlled by the pull-up control signal; And pull-down parallel resistors that pull down the input / output node while being turned on / off in response to each pull-down calibration code during pull-down termination driving, wherein at least one of the pull-down parallel resistors is turned on by a pull-down control signal. And a pull-down termination resistor, characterized in that the strength is controlled.

Here, the control of the strength of the turn-on means that the amount of current flowing when it is turned on is controlled.

Therefore, the strength of the turn-on of some of the parallel resistors can be adjusted by the pull-up and pull-down control signals. The intensity of the turn-on is adjusted to cause a change in the overall resistance of the pull-up termination resistor and pull-down termination resistor, which allows the termination resistance to reach the target resistance.

In addition, by adjusting the strength of the turn-on of some resistors, a change occurs in the termination strength, which makes it possible to adjust the current value flowing in the input / output node. That is, it is possible to change the I-V curve (current-voltage curve) characteristics of the input and output nodes by adjusting the strength of the turn-on of some resistors.

The calibration circuit of the on-die termination device according to another embodiment of the present invention (showing a case having only one, not all of the pull-up or pull-down termination resistors) is turned on / off in response to each of the calibration codes. And a parallel resistor for terminating the input / output node while being off, wherein at least one of the parallel resistors includes a termination resistor, characterized in that the strength of the turn-on is controlled by a control signal.

Therefore, the intensity of the turn-on of some of the parallel resistors can be adjusted by the control signal. The intensity of the turn-on of some resistors is adjusted to cause a change in the overall resistance value of the termination resistor portion, which allows the termination resistance value to reach the target resistance value.

In addition, the strength of the turn-on of some resistors is controlled to cause translational termination, which makes it possible to adjust the current value flowing through the input / output nodes. That is, it is possible to change the I-V curve characteristics of the input and output nodes by adjusting the strength of the turn-on of some resistors.

The termination circuit of the on-die termination device according to the present invention is characterized by being capable of changing the amount of current flowing at the turn-on of some termination resistors under the control of a control signal.

Therefore, it is possible to change the termination resistance value, which has the effect of correcting the error so that the termination circuit reaches the target resistance value. In addition, since the amount of current flowing through the input / output node can be controlled by controlling the strength of the turn-on, the characteristic of the I-V curve of the input / output node can be changed.

DETAILED DESCRIPTION Hereinafter, the most preferred embodiments of the present invention will be described with reference to the accompanying drawings so that those skilled in the art may easily implement the technical idea of the present invention.

3 is a configuration diagram of a termination circuit of an on die termination apparatus according to an embodiment of the present invention.

As shown in the figure, the termination circuit of the on-die termination device according to an embodiment of the present invention, the pull-up calibration code (UP <0: 5>, the pull-up termination driving PCODE <0: 5 when the pull-up termination driving > = UP <0: 5>) and pull-up parallel resistors 330, 340, and 350 that pull up and drive the input / output node DQ in response to each of the pull-up parallel resistors 330, One or more of the 340, 350 (350) is a pull-up termination resistor 320, characterized in that the amount of current flowing at its turn on by the pull-up control signals (TM_UP0, TM_UP1) is controlled; And I / O nodes (DQ) that are turned on and off in response to pulldown calibration codes (DN <0: 5> and pulldown termination NCODE <0: 5> = DN <0: 5>) respectively. And pull down parallel resistors 380, 390, and 400, and one or more of the pull down parallel resistors 380, 390, and 400 are connected by their pull-down control signals TM_DN0 and TM_DN1. And a pull-up termination resistor unit 370, characterized in that the amount of current flowing at turn-on is controlled.

The figure shows an output driver (Dout Driver or Output Driver) of a semiconductor memory device as an example of a termination circuit. In this case, the termination circuit includes a predriver 300 as a control circuit. The pre-driver unit 300 turns on the pull-up termination resistor 320 when the high-output data is output so that the pull-up termination resistor 320 drives the input / output node DQ to pull up the input / output node ( When the DQ) is 'high' and the 'low' data is output, the pull-down termination resistor 370 is turned on so that the pull-down termination resistor 370 pulls down the input / output node DQ to drive input / output. Put the output node DQ 'low'.

When the pre-driver 300 outputs the 'high' data, the pre-driver 300 adjusts the pull-down calibration code (DN <0: 5>) input to the pull-down termination resistor 370 to be inactivated and adjusts the 'low' data. When outputting, all of the pull-up calibration codes UP <0: 5> input to the pull-up termination resistor 320 are deactivated. In summary, when high data is output (PCODE <0: 5> = UP <0: 5>, DN <0: 5> = all are disabled), when low data output is (NCODE <0: 5> = DN <0: 5>, UP <0: 5> = all disabled).

When the termination circuit is a circuit other than the output driver of the semiconductor memory device, the termination circuit may include a control circuit of another type other than the predriver 300 shown in the drawing. Regardless of which control circuit is included, the pull-up termination resistor 320 is used to terminate the input / output node DQ as a pull-up, and the pull-down termination resistor 370 is used to terminate the input / output node DQ as a pull-down. There is no change in the fact that it is used, and the termination resistors 320 and 370 terminate the input / output node DQ only by pull-up or pull-down only or pull-up and pull-down under the control of the control circuit. Depends on the interface regulations of the system to which the circuit is applied).

The pull-up termination resistor 320 is internally responsive to the pull-up calibration code UP <0: 5> during pull-up termination driving and UP <0: 5> = PCODE <0: 5> during pull-up termination driving. The pull-up parallel resistors 330, 340, and 350 are turned on and off and drive the input / output node DQ. However, unlike the prior art, some of the internal pull-up parallel resistors 330, 340, and 350 are characterized in that the strength of the turn-on is controlled by the pull-up control signals TM_UP0 and TM_UP1.

In detail, the pull-up termination resistor 320 includes pull-up switching means 331, 341, and 351 turned on / off in response to each of the pull-up calibration codes UP <0: 5>; And pull-up parallel resistors 330, 340, and 350 that are turned on and off by the pull-up switching means 331, 341, and 351, respectively, and at least one of the pull-up switching means 331, 341, and 351. In step 351, the strength of the turn-on is adjusted by the pull-up control signals TM_UP0 and TM_UP1.

That is, the pull-up switching means 351 whose intensity of turn-on is adjusted is determined by the pull-up calibration code UP <5> assigned to it whether the pull-up switching means 351 is turned on or off, but how strongly it is turned on. And controlled by pull-up control signals TM_UP0 and TM_UP1.

The pull-up switching unit 351 to which the intensity of the turn-on is adjusted includes a plurality of pull-up transistors 352, 353, and 354 connected in parallel. Whether the pull-up transistors 352, 353 and 354 are turned on or off is determined by the pull-up calibration code UP <5> assigned to the pull-up switching means 351 itself. How many transistors 354 to turn on (i.e., the number of transistors to be used) is determined by the pull-up control signals TM_UP0 and TM_UP1.

This may be configured such that some of the pull-up transistors 353 and 354 ignore the pull-up calibration code UP <5> under the control of the pull-up control signals TM_UP0 and TM_UP1. In detail, some of the pull-up transistors 353 and 354 are not configured to directly receive the pull-up calibration code UP <5>, but the pull-up control signals TM_UP0 and TM_UP1 and the pull-up calibration code UP <5. Is configured to be logically input by the oragates 355 and 356, the pull-up transistors (UP <5>) are independent of the pull-up calibration code UP <5> when the pull-up control signals TM_UP0 and TM_UP1 are enabled. 353 and 354 are always off.

The pull-down termination resistor unit 370 responds to the pull-down calibration code DN <0: 5> when the pull-down termination is driven and DN <0: 5> = NCODE <0: 5> when the pull-down termination is driven. The parallel resistors 380, 390, and 400 are turned on and off and pull down the input / output node DQ. In addition, some of the internal pull-down parallel resistors 380, 390, and 400 may adjust the strength of the turn-on by the pull-down control signals TM_DN0 and TM_DN1.

That is, the pull-down termination resistor unit 370 operates in the same manner as the pull-up termination resistor unit 320 and has the same characteristics as the pull-up termination resistor unit 370.

The pull-down termination resistor unit 370 includes pull-down switching means 381, 391, and 401 turned on / off in response to each of the pull-down calibration codes DN <0: 5>; And pull-down parallel resistors 380, 390, and 400 that are turned on and off by pull-down switching means 381, 391, and 401, respectively. 401 is characterized in that the strength of the turn-on is controlled by the pull-down control signals (TM_DN0, TM_DN1).

The pull-down switching means 401 whose intensity of turn-on is adjusted includes a plurality of pull-down transistors 402, 403, and 404 connected in parallel, and pull-down switching means to turn on or off the pull-down transistors 402, 403, and 404. 401 is determined by the pull-down calibration code DN <5> assigned to it, but how many of the pull-down transistors 402, 403, and 404 are to be turned on by the pull-down control signals TM_DN0 and TM_DN1. Characterized in that it is determined.

This may be configured so that some of the pull-down transistors 403 and 404 ignore the pull-down calibration code DN <5> under the control of the pull-down control signals TM_0 and TM_1. In detail, some of the pull-down transistors 403 and 404 do not directly input the pull-down calibration code DN <5>, but instead of the inverted pull-down control signals TM_DN0b and TM_DN1b and the pull-down calibration code DN. <5> is configured to be logically inputted by the AND gates 405 and 406 to enable input of the pull-down control signals TM_UP0 and TM_UP1 (TM_DN0b, TM_DN1b 'low') pull-down calibration code (DN <). 5>, pull-down transistors 403 and 404 are always off.

The present invention allows the strength of the turn-on of some parallel resistors 350 and 400 in the pull-up and pull-down termination resistors 320 and 370 to be adjusted by the pull-up and pull-down control signals TM_UP0, TM_UP1, TM_DN0 and TM_DN1. When the strength of the turn-on of the pull-up and pull-down switching means 351 and 401 is adjusted by adjusting the pull-up and pull-down control signals TM_UP0, TM_UP1, TM_DN0 and TM_DN1, the pull-up parallel resistor 350 and the pull-down parallel resistor 400 are adjusted. It is possible to adjust the amount of current flowing through each. If the amount of current flowing through the pull-up parallel resistor 350 and the pull-down parallel resistor 400 is different, it affects the voltage level of the input / output node DQ, which has the same effect as the termination resistance value is actually changed (transistor used. Since the number of the transistors is also controlled, a resistance value change is caused by a transistor having a resistance component). Therefore, it is possible to overcome the error of the termination resistance value due to mismatch between the calibration circuit (FIG. 1) and the termination circuit (FIG. 3).

In addition, since the amount of current flowing through the input / output node DQ can be directly controlled by the pull-up and pull-down control signals TM_UP0, TM_UP1, TM_DN0, TM_DN1, the current-voltage curve of the input / output node DQ ( If the IV curve is out of the desired value, it can be adjusted.

In FIG. 3, only one resistor 350 and 400 in each of the pull-up termination resistor 320 and the pull-down termination resistor 370 are controlled to adjust the amount of current flowing at turn-on. However, this is only one example. Even if many resistors (eg, 340, 350, 390, 400) are configured to control the amount of current flowing at turn-on, the object of the present invention can be achieved equally. In the case where only a small number of resistors 350 and 400 allow the amount of current flowing at turn-on, as shown in FIG. It is advantageous to set the resistors 350 and 400 having a large resistance value among the 390 and 400. This is because a large range of errors can be corrected even if the amount of current flowing at the turn-on of one resistor 350 or 400 is adjusted for each resistor unit 320 or 370.

The pull-up and pull-down control signals TM_UP0, TM_UP1, TM_DN0 and TM_DN1 are test mode signals that allow the logic level to be changed by the mode register setting (MRS) or to change the logic level according to the cutting information of the fuse circuit. It can be controlled in various ways.

4 is a diagram illustrating a change in a current-voltage curve at an input / output node DQ according to the present invention.

The upper part of the figure shows the current-voltage curve at the input / output node DQ at the pull-up termination and the lower part at the pull-down termination. As shown in the figure, the pull-up and pull-down control signals TM_UP0, TM_UP1, TM_DN0, when the current current-voltage curve is out of the target current-voltage curve that the input / output node DQ should originally have TM_DN1) may be adjusted to draw the same curve as the target current-voltage curve.

Arrows in the figure indicate that the current-voltage curve of the input / output node DQ is changed by adjusting the control signals TM_UP0, TM_UP1, TM_DN0, TM_DN1.

5 is a configuration diagram of a termination circuit of an on die termination device according to another embodiment of the present invention.

As shown in the figure, the termination circuit of the on-die termination device is turned on in response to each of the calibration codes UP <0: 5> and PCODE <0: 5> = UP <0: 5> in the termination operation. And parallel resistors 520, 530, and 540 for terminating the input / output node DQ while being turned on and off, wherein one or more of the parallel resistors 520, 530, and 540 are control signals TM0 and TM1. Termination resistance unit 510, characterized in that the amount of current flowing through it is controlled by the turn on. And it may include a control circuit 500 for controlling this. Although termination resistor 510 is shown in the form of a pull-up in the drawing, it may be implemented in the form of a pull-down depending on the system to which the termination circuit is applied.

The control circuit 500 is a circuit for enabling the termination resistor unit 510 during the termination operation. When the termination circuit does not need to be performed, all the control codes input to the termination resistor unit 510 are UP <0: 5>) value is turned off to turn off the termination resistor unit 510. In the case of a GDDR semiconductor memory device, when data is input, it is prescribed to receive data while the input / output node DQ is terminated by a pull-up. Therefore, when the termination circuit of FIG. 5 is applied to the input buffer side of the GDDR semiconductor memory device, the control circuit 500 activates the termination resistor unit 510 when data is input.

5 and 3 only differ in whether the termination resistors 320, 370, 510 have both pull-up and pull-down or only one. For example, when the termination circuit is an output driver, both the pull-up and pull-down termination resistors 320 and 370 should be provided as shown in FIG. 3, but when the termination circuit is applied to the input buffer side, a single one as shown in FIG. Only the termination resistor unit 510 is provided.

When the termination resistor unit 510 of FIG. 5 is a pull-up termination resistor unit as shown in the drawing, the configuration and operation of the pull-up termination resistor unit 320 described with reference to FIG. 3 are the same, and the termination resistor unit 510 of FIG. In the case of the pull-down termination resistor unit shown in FIG. 3, the configuration and operation of the pull-down termination resistor unit 370 described in FIG. 3 are the same, and thus the detailed description thereof will be omitted.

Although the technical spirit of the present invention has been described in detail according to the above preferred embodiment, it should be noted that the above-described embodiment is for the purpose of description and not of limitation. In addition, it will be appreciated by those skilled in the art that various embodiments are possible within the scope of the technical idea of the present invention.

1 is a block diagram of a portion (calibration circuit) for performing a ZQ calibration operation in a conventional on-die termination device.

2 is a diagram illustrating an output driver (termination circuit of an on die termination device) of a semiconductor memory device using calibration codes PCODE <0: N> and NCODE <0: N> generated by the calibration circuit of FIG. 1. Figure showing determining the termination resistance value.

3 is a block diagram of a termination circuit of the on-die termination device according to an embodiment of the present invention.

4 shows that a change occurs in the current-voltage curve at an input / output node DQ in accordance with the present invention.

5 is a configuration diagram of a termination circuit of an on die termination device according to another embodiment of the present invention.

Claims (14)

A pull-up parallel resistor that pulls up an input / output node while being turned on / off in response to each pull-up calibration code when the pull-up termination is driven, wherein at least one of the pull-up parallel resistors is turned on by the pull-up control signal. A pull-up termination resistor, characterized in that the amount of current flowing in the control is controlled; And Pull down parallel resistors that pull down the input / output node while being turned on and off in response to each of the pull down calibration codes during pull down termination driving, one or more of the pull down parallel resistors being turned on by a pull down control signal; Pull-down termination resistor, characterized in that the amount of current flowing through it is controlled Termination circuit of the on-die termination device comprising a. The method of claim 1, The termination circuit is, An output driver of a semiconductor memory device, When outputting 'high' data, the pull-up termination resistor pulls up the input / output node. The pull-down termination resistor unit pulls down the input / output node when outputting the 'low' data, the termination circuit of the on-die termination device. The method of claim 2, The termination circuit is, Further comprising a pre-driver section for controlling the pull-up termination resistor and the pull-down termination resistor, The predriver section, Deactivating all pull-down termination codes input to the pull-down termination resistor section when outputting 'high' data, and deactivating all pull-up termination codes input to the pull-up termination resistor section when outputting 'low' data. Termination circuit of the on-die termination device. The method of claim 1, The pull-up termination resistor unit may include pull-up switching means turned on / off in response to each of the pull-up calibration codes; And the pull-up parallel resistors each turned on / off by the pull-up switching means, The pull-down termination resistor unit may include pull-down switching means turned on / off in response to each of the pull-down calibration codes; And the pull-down parallel resistors each turned on / off by the pull-down switching means, One or more of the pull-up switching means adjusts the amount of current that they pass at turn-on in response to the pull-up control signal, and one or more of the pull-down switching means passes at their turn-on in response to the pull-down control signal. Termination circuit of the on-die termination device, characterized in that for controlling the amount of current to be. The method of claim 4, wherein Pull-up switching means that the current amount is adjusted, It includes a plurality of pull-up transistors connected in parallel, it is determined by the pull-up calibration code assigned to it whether to turn on or off the pull-up transistors, but how many of the pull-up transistors to turn on the pull-up control signal Is determined by Pull-down switching means that the current amount is adjusted, It includes a plurality of pull-down transistors connected in parallel, it is determined by the pull-down calibration code assigned to it whether to turn on or off the pull-down transistors, but how many of the pull-down transistors to turn on the pull-down control signal Termination circuit of the on-die termination device, characterized in that determined by. The method of claim 1, The pull-up control signal and the pull-down control signal, The logic of the on-die termination device characterized in that the logic value is determined by the mode register setting or the cutting information of the fuse circuit. The method of claim 1, The pull-up parallel resistance in which the amount of current is adjusted during the turn-on of the pull-up parallel resistors, characterized in that the pull-up parallel resistor having a relatively large resistance value of the pull-up parallel resistors, The pull-down parallel resistance of the current pull-down parallel resistance of the pull-down parallel resistance is a pull-down parallel resistance having a relatively large resistance value of the pull-down parallel resistance, the termination circuit of the on-die termination device. And parallel resistors for terminating an input / output node while being turned on and off in response to each calibration code, wherein at least one of the parallel resistors is configured to control the amount of current flowing in itself when turned on by a control signal. Termination resistor Termination circuit of the on-die termination device comprising a. The method of claim 8, The termination circuit is, And a termination circuit of the on-die termination device, which is applied to an input buffer side of a semiconductor memory device and terminates the input / output pad with a pull-up when receiving data. The method of claim 9, The termination circuit is, And a control circuit for controlling the termination resistor unit to terminate the operation only when data is input. The method of claim 8, The termination resistor unit, Switching means turned on / off in response to each of the calibration codes; And Parallel resistors connected in parallel to the calibration node and turned on / off by the switching means, At least one of said switching means adjusts the amount of current it passes through at turn-on in response to said control signal. The method of claim 11, The switching means for adjusting the amount of current, It includes a plurality of transistors connected in parallel and whether to turn them on or off is determined by the calibration code assigned to them. How many of the transistors to turn on the termination circuit of the on-die termination device characterized in that determined by the control signal. The method of claim 8, The control signal is The logic of the on-die termination device characterized in that the logic value is determined by the mode register setting or the cutting information of the fuse circuit. The method of claim 8, Among the parallel resistors, a parallel resistor in which the amount of current is adjusted at turn-on, And a parallel resistor having a relatively large resistance value among the parallel resistors.

Images