KR20100077642A - On die termination and method for controlling the same, semiconductor memory device including the same - Google Patents

Abstract

PURPOSE: An on-die termination and a method for controlling the same are provided to compensate the variation of the whole resistance of the semiconductor memory device by comparing on-die termination resistance with reference resistance. CONSTITUTION: A termination resistor unit(201) comprises a plurality of resistance units(203,205,207,209,211,213). The resistance of a plurality of resistance unit is controlled in response to a termination control signal. A resistance sensor(219) senses the resistance error of the termination resistor unit. The resistance sensor outputs a resistance sensing signal. Resistance control parts(215,217) are connected in parallel with the termination resistor unit and control the resistance.

Description

ON DIE TERMINATION AND METHOD FOR CONTROLLING THE SAME, SEMICONDUCTOR MEMORY DEVICE INCLUDING THE SAME}

The present invention relates to an on die termination device and a control method, and a semiconductor memory device including the same, and more particularly, to an on die termination device and a control method capable of maintaining a constant resistance value, and a semiconductor memory device including the same.

As the operating speed of electrical products increases, the swing width of signals interfaced between semiconductor devices is gradually decreasing. The reason is to minimize the delay time for signal transmission. As the swing width of the signal decreases, the influence on external noise increases, and the reflection of the signal due to impedance mismatching in the interface stage becomes more severe. Impedance mismatch occurs due to external noise, fluctuations in power supply voltage, changes in operating temperature, or changes in manufacturing processes. When impedance mismatch occurs, it is difficult to transmit data at high speed, and output data output from the data output terminal of the semiconductor device may be distorted.

Therefore, in order to solve the above-mentioned problems, a memory device requiring a high speed of operation employs an impedance matching circuit called On Die Termination in the vicinity of a pad in an integrated circuit chip. 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. The signal integrity characteristic can be improved by the on die termination device.

1 is a diagram illustrating a conventional on-die termination apparatus 101 and an output driver 115 together.

The on-die termination device 101 includes a plurality of pull-up termination resistors 103, 105, and 107 and pull-down termination resistors which are turned on / off in response to the termination control signals PCODE <1: 3> and NCODE <1: 3>. Means 109, 111, 113. Each of the pull-up termination resistors 103, 105, and 107 and each of the pull-down termination resistors 109, 111, and 113 are turned on one by one in response to the termination control signals PCODE <1: 3> and NCODE <1: 3>. Is turned off. The termination control signal PCODE <1: 3> may be adjusted to a code value from '111' to '110', '100', or '000', and correspondingly to the termination control signal NCODE <1: 3>. The code value may be adjusted from '000' to '001', '011', and '111'. The termination control signals PCODE <1: 3> and NCODE <1: 3> may be generated in the mode register set (MRS), and the on die termination device 101 may be enabled by the mode register set (MRS). It can work.

For example, the resistance value of each of the pull-up termination resistors 103, 105 and 107 and the pull-down termination resistors 109, 111 and 113 may be 300 ohms, and the pull-up termination resistors 103, 105 and 107 and the pull-down As the termination resistance means 109, 111, 113 are turned on one by one, the total resistance of the on-die termination device 101 decreases to 150 ohms, 75 ohms, and 50 ohms. Impedance matching with the outside of the semiconductor device is achieved by the overall resistance value of the on die termination device 101.

The output driver 115 drives the data DATA and outputs the data to the DQ pad 117.

On the other hand, the on die termination device 101 may simultaneously perform the role of the output driver 115. The on-die termination device 101 outputs 'high' data by the pull-up termination resistors 103, 105, and 107 in response to the data, and pull-down termination resistors 109, 111, and 113 pull down. You can output 'low' data by performing an operation. At this time, the on-die termination apparatus 101 may further include a pre-driver, and the pre-driver inputs data and termination control signals PCODE <1: 3> and NCODE <1: 3>. The pull-up termination resistors 103, 105, and 107 and the pull-down termination resistors 109, 111, and 113 may be pulled up or pulled down.

Meanwhile, the resistance values of the pull-up termination resistance means 103, 105, and 107 and the pull-down termination resistance means 109, 111, and 113 may fluctuate due to PVT (Process, Voltage, Temperature) variation. In particular, the resistance value of the MOS transistor may be changed in response to the change in the process. Fluctuations in the resistance values of the pull-up termination resistance means 103, 105, 107 and pull-down termination resistance means 109, 111, 113 cause fluctuations in the overall resistance value of the on-die termination device 101, and thus the on-die termination device (101) The total resistance value cannot be the intended resistance value. That is, the overall resistance value of the on die termination device 101 may be a value other than 150 ohms, 75 ohms, and 50 ohms intended by design.

As a result, variations in the overall resistance value of the on-die termination device 101 may cause impedance mismatch and deteriorate signal fidelity (SI) characteristics.

SUMMARY OF THE INVENTION The present invention has been proposed to solve the above problems, and an object thereof is to provide an on die termination apparatus and a control method capable of compensating for a variation in a resistance value of an on die termination apparatus, and a semiconductor memory device including the same.

The present invention for achieving the above object is a termination resistor unit including a plurality of resistance means for adjusting the resistance value in response to the termination control signal; A resistance value detector for detecting a resistance value error of the termination resistor and outputting a resistance value detection signal; And a resistance value adjusting unit connected in parallel with the termination resistor and on / off in response to the resistance value detecting signal and adjusting a resistance value.

The present invention also provides an output driver for outputting data by terminating a data output node by pull-up or pull-down using a plurality of resistance means turned on / off in response to a termination control signal; A resistance value detector for detecting a difference between resistance values of the plurality of resistance means and outputting a resistance value detection signal; And a resistance value controller connected in parallel to the termination resistor and on / off in response to the resistance value detection signal and configured to adjust a resistance value.

In addition, the present invention for achieving the above object comprises the steps of performing a pull-up termination operation with a first resistance value according to the termination control signal for impedance matching; Performing a pull-down termination operation with a second resistance value according to the termination control signal for impedance matching; Detecting a difference between the first resistance value and the second resistance value and outputting a resistance value detection signal; And adjusting each of the first and second resistance values in response to the resistance value detection signal.

According to the present invention, the resistance value of the on-die termination device is compared with a predetermined reference voltage and adjusted according to the comparison result to compensate for the variation in the overall resistance value of the on-die termination device and the semiconductor memory device including the same according to the PVT variation. Can be.

Therefore, impedance mismatch and SI characteristic deterioration can be prevented.

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.

2 is a diagram illustrating an on-die termination device according to a first embodiment of the present invention.

As shown in FIG. 2, the on-die termination apparatus according to the present invention includes a termination resistor 201, a resistance value detector 219, and resistance resistors 215 and 217.

The termination resistor unit 201 is turned on / off in response to the termination control signals PCODE <1: 3> and NCODE <1: 3> for impedance matching, and includes a plurality of resistance means 203 and 205 for adjusting the resistance value. , 207, 209, 211, and 213.

The plurality of resistor means 203, 205, 207, 209, 211, 213 includes pull-up termination resistor means 203, 205, 207 and pull-down termination resistor means 209, 211, 213. In FIG. 2, the plurality of resistance means 203, 205, 207, 209, 211, and 213 include three pull-up termination resistance means 203, 205, and 207 and pull-down termination resistance means 209, 211, and 213. The case is described as an embodiment.

 Each of the pull-up termination resistors 203, 205 and 207 and the pull-down termination resistors 209, 211 and 213 are turned on / off in response to the termination control signals PCODE <1: 3> and NCODE <1: 3>. , Is connected to node X. The total resistance value of the termination resistor unit 201 is determined according to the on / off of each of the pull-up termination resistor means 203, 205, and 207 and the pull-down termination resistor means 209, 211, and 213. The termination control signals PCODE <1: 3> and NCODE <1: 3> may be generated in the mode register set MRS. In FIG. 2, the case where the resistance values of each of the pull-up termination resistance means 203, 205, and 207 and the pull-down termination resistance means 209, 211, and 213 are all the same will be described as an example.

The resistance value detector 219 is a difference between the total resistance value of the pull-up termination resistance means 203, 205, and 207 and the total resistance value of the pull-down termination resistance means 209, 211, and 213 according to the PVT variation, that is, the termination resistance portion. The resistance value error of 201 is sensed and the resistance value detection signals TRIM_P <1: 2> and TRIM_N <1: 2> are output according to the detection result.

As described above, although the pull-up termination resistance means 203, 205 and 207 and the pull-down termination resistance means 209, 211 and 213 are each designed to have the same resistance value, the pull-up termination resistance means 203 and 205 due to PVT fluctuations. 207 and the pull-down termination resistance means 209, 211 and 213 may vary in resistance, which may cause impedance mismatch. The resistance value detector 219 detects the difference in the resistance value, that is, the difference between the total resistance value of the pull-up termination resistance means 203, 205, and 207 and the total resistance value of the pull-down termination resistance means 209, 211, and 213. The result is output as a resistance value detection signal TRIM_P <1: 2> and TRIM_N <1: 2>. The resistance value adjusting units 215 and 217 to be described later may perform impedance matching in response to the resistance value detection signals TRIM_P <1: 2> and TRIM_N <1: 2>.

The resistance value detector 219 compares the voltage VX of the node X with the reference voltage VREF. The reference voltage VREF may be generated by the resistance value detector 219. The reference voltage VREF is the voltage VX of the node X when the total resistance value of the pull-up termination resistance means 203, 205, 207 and the total resistance value of the pull-down termination resistance means 209, 211, 213 are the same. / 2. Therefore, when the voltage VX of the node X does not become VDD / 2, the total resistance values of the pull-up termination resistance means 203, 205, and 207 and the pull-down termination resistance means 209, 211, and 213 are varied, and the resistance The value detector 219 detects this and outputs resistance value detection signals TRIM_P <1: 2> and TRIM_N <1: 2>. A detailed description of the resistance value detector 219 will be described later with reference to FIG. 3.

The resistance value controllers 215 and 217 are connected in parallel to the termination resistor unit 201 and are turned on / off in response to the resistance value detection signals TRIM_P <1: 2> and TRIM_N <1: 2>. Adjusted. That is, each of the resistance value adjusting units 215 and 217 is connected in parallel to each of the plurality of resistance means 203 and 209, and the overall resistance value and the pull-down termination resistance means 209 of the pull-up termination resistance means 203, 205 and 207. , 211, 213 to compensate for the difference in the total resistance values. In FIG. 2, each of the resistance value adjusting units 215 and 217 includes two resistance means turned on / off in response to the resistance value detection signals TRIM_P <1: 2> and TRIM_N <1: 2>. Described as one embodiment.

Each of the resistance adjusting units 215 and 217 includes NMOS transistors and PMOS transistors as active resistors. The resistance value adjusting units 215 and 217 may further include a resistor (passive element), such as a plurality of resistance means 203, 205, 207, 209, 211, and 213.

Since each of the resistance value adjusting units 215 and 217 is connected in parallel to each of the pull-up and pull-down termination resistor units 203 and 209, the resistance value adjustment as the resistance means included in the resistance value adjusting units 215 and 217 is turned on. The total resistance values of the portions 215 and 217 and the plurality of resistance means 203, 205, 207, 209, 211 and 213 become small. Here, the total resistance value means the total sum of resistance values connected in parallel.

For example, when the resistance means of the resistance value adjusting unit 215 is turned on, the overall resistance values of the pull-up termination resistance means 203, 205, and 207 and the resistance value adjusting unit 215 are reduced, and the resistance value adjusting unit ( When the resistance means of 217 is turned on, the total resistance values of the pull-down termination resistance means 209, 211, and 213 and the resistance value adjusting part 217 are reduced. On the other hand, since the on-die termination device according to the present invention is turned on and off from the pull-up and pull-down termination resistors 203 and 209 in response to the termination control signals PCODE <1> and NCODE <1>, the resistance value is adjusted. The resistance value adjusting units 215 and 217 are preferably connected in parallel to the pull-up and pull-down termination resistors 203 and 209.

As a result, according to the present invention, the overall resistance value is adjusted by the resistance value adjusting units 215 and 217, the voltage VX of the node X can be maintained at VDD / 2, and impedance matching can be performed, and deterioration of the SI characteristic is achieved. Can be prevented.

3 is a diagram illustrating the resistance value detector 219 shown in FIG. 2 in more detail.

As shown in FIG. 3, the resistance value detector 219 according to the present invention includes a reference voltage generator 301 and a voltage comparator 303.

The reference voltage generator 301 includes a plurality of resistors and distributes the power supply voltage VDD to generate the reference voltage VREF of VDD / 2. The reference voltage generator 301 further generates additional reference voltages VREF_A and VREF_B so that the voltage comparator 303 can detect the change in the node X voltage VX of the on-die termination device in more detail. . Each of the additional reference voltages VREF_A and VREF_B is larger or smaller than the reference voltage VREF by a predetermined value.

The voltage comparator 303 includes a plurality of comparison means 304 to 306 for comparing the voltage VX of the node X with the reference voltage VREF and the additional reference voltages VREF_A and VREF_B.

Each of the comparison means 304 to 306 outputs a low level signal when the reference voltage VREF and the additional reference voltages VREF_A and VREF_B are larger based on the voltage VX of the node X. If VREF) and the additional reference voltages VREF_A and VREF_B are smaller, a high level signal is output. More specifically, the first comparing means 304 compares the voltage VX of the node X with the additional reference voltage VREF_A and outputs a resistance value detection signal TRIM_N <2>. The second comparing means 305 compares the voltage VX of the node X with the reference voltage VREF and outputs the resistance value detection signals TRIM_N <1> and TRIM_P <1>. Finally, the third comparing means 306 compares the voltage VX of the node X with the additional reference voltage VREF_B and outputs a resistance value detection signal TRIM_P <2>.

Hereinafter, the operation of the resistance value detector 219 will be described in more detail.

When the voltage VX of the node X is smaller than the additional reference voltage VREF_B, the resistance value of the pull-up termination resistance means 203, 205, and 207 in the termination resistor portion 201 is the pull-down termination resistance means 209, 211, and 213. This is larger than the resistance value of). The plurality of comparison means 304 to 306 all output low-level resistance value detection signals TRIM_P <1: 2> and TRIM_N <1: 2>. Therefore, all the resistance means of the resistance value adjusting unit 215 is turned on, and all the resistance means of the resistance value adjusting unit 217 are turned off. As a result, the overall resistance of the resistance adjusting unit 215 and the pull-up termination resistance means 203, 205, and 207 can be reduced.

When the voltage VX of the node X is smaller than the reference voltage VREF and larger than the additional reference voltage VREF_B, the resistance values of the pull-up termination resistors 203, 205, and 207 are also pull-down termination resistors 209 and 211. , 213). In this case, however, the resistance values of the pull-up termination resistance means 203, 205, and 207 and the pull-down termination resistance means 209, 211, and 213 are smaller than the voltage VX of the node X is smaller than the additional reference voltage VREF_B. This is the case where the difference in resistance is small.

The third comparison means 306 outputs a high level resistance value detection signal TRIM_P <2>, and the remaining comparison means 304 and 305 are low level resistance value detection signals TRIM_P <1> and TRIM_N <1: 2>). Therefore, only the resistance means receiving the resistance detection signal TRIM_P <1> from the resistance adjustment unit 215 is turned on. The overall resistance of the resistance adjusting unit 215 and the pull-up termination resistance means 203, 205, 207 can be reduced, but less than if the voltage VX of the node X is smaller than the additional reference voltage VREF_B. .

When the voltage VX of the node X is greater than the reference voltage VREF and less than the additional reference voltage VREF_A, the resistance value of the pull-down termination resistance means 209, 211, 213 is the pull-up termination resistance means 203, 205, 207. This is larger than the resistance value of). In this case, only the first comparing means 303 outputs the low level resistance value detection signal TRIM_N <2>. Therefore, only the resistance means receiving the resistance value detection signal TRIM_N <1> from the resistance value controller 217 is turned on. Therefore, the overall resistance value of the resistance value adjusting unit 217 and the pull-down termination resistance means 209, 211, and 213 can be reduced.

When the voltage VX of the node X is larger than the additional reference voltage VREF_A, the resistance value of the pull-down termination resistance means 209, 211, and 213 is also larger than the resistance value of the pull-up termination resistance means 203, 205, and 207. to be. However, the resistance value of the pull-down termination resistor means 209, 211, and 213 and the pull-up termination resistor means 203 and 205 are greater than the case where the voltage VX of the node X is larger than the reference voltage VREF and smaller than the additional reference voltage VREF_A. , 207) has a large difference in resistance.

The plurality of comparison means 304 to 306 all output high-level resistance value detection signals TRIM_P <1: 2> and TRIM_N <1: 2>. Therefore, the resistance means of the resistance value control unit 217 is all turned on, the total resistance value of the resistance value control unit 217 and the pull-down termination resistance means (209, 211, 213) can be reduced.

According to the design, the number of resistance means included in each of the resistance value adjusting units 215 and 217 may be changed, and the resistance value detecting unit 219 may output a resistance value detecting signal in response thereto. When the number of resistance means included in each of the resistance value controllers 215 and 217 increases, the resistance value detector 219 decodes the signals output from the plurality of comparison means 304 to 306 to adjust the resistance value controller. The resistance value detection signals corresponding to 215 and 217 may be output.

As described above, the termination resistor unit 201 outputs 'high' data to the DQ pad 221 by the pull-up termination resistor means 203, 205, and 207 in response to the data, and pull-down termination resistor. The means 209, 211, and 213 perform a pull-down operation to output 'low' data to the DQ pad 221 and operate as an output driver. Here, node X transfers data to DQ pad 221 as a data output node.

4 is a diagram illustrating an on-die termination device according to a second embodiment of the present invention.

As shown in FIG. 4, the on-die termination apparatus according to the present invention includes a termination resistor 401, a resistance value detector 421, and a resistance value controller 415 to 420.

The operation process of the on die termination apparatus shown in FIG. 2 and the on die termination apparatus shown in FIG. 4 are the same. However, unlike the on-die termination device shown in FIG. 2, the on-die termination device shown in FIG. 4 includes pull-up termination resistance means 403, 405, and 407 and pull-down termination resistance means 409 included in the termination resistor part 401. Resistance controllers 415 to 420 are connected in parallel to each of, 411 and 413.

Meanwhile, as described above, each of the pull-up termination resistance means 403, 405, 407 and the pull-down termination resistance means 409, 411, 413 is connected to the termination control signals PCODE <1: 3> and NCODE <1: 3>. Answer on / off. The resistance value detection signals TRIM_P <1: 2> and TRIM_N <1: 2> are not inputted to the resistance value control unit connected to the pull-up and pull-down termination resistors which are turned off by using a predetermined passgate, and are turned off. The resistance value controller connected in parallel to the pull-up and pull-down termination resistors can be designed to be turned off. In this case, the predetermined passgate may be turned on / off in response to a termination control signal input to the turned-up pull-up termination resistor and pull-down termination resistor.

Although the present invention has been described in terms of the apparatus, the operation of each component constituting the on-die termination device according to the present invention can be easily understood from the process point of view. Therefore, the operation of each component constituting the on-die termination device according to the present invention can be understood as each step of configuring the on-die termination device control method according to the principles of the present invention. Hereinafter, a method of controlling an on die termination apparatus will be described with reference to FIGS. 2 to 3.

The on-die termination control method according to the present invention includes performing a pull-up termination operation with a first resistance value according to a termination control signal (PCODE <1: 3>) for impedance matching; Performing a pull-down termination operation with a second resistance value according to the termination control signal NCODE <1: 3> for impedance matching; Detecting a difference between the first resistance value and the second resistance value and outputting a resistance value detection signal (TRIM_P <1: 2>, TRIM_N <1: 2>); And adjusting each of the first and second resistance values in response to the resistance value detection signals TRIM_P <1: 2> and TRIM_N <1: 2>.

The pull-up termination resistors 203, 205, and 207 perform a termination operation with the first resistor value in response to a termination control signal PCODE <1: 3>. The pull-down termination resistors 209, 211, and 213 In response to a termination control signal NCODE <1: 3>, a termination operation is performed with the second resistance value. The first resistance value and the second resistance value are designed to be the same, but may vary with PVT variation.

The outputting of the resistance value detection signals TRIM_P <1: 2> and TRIM_N <1: 2> may be performed by the same voltage as the termination voltage when the first resistance value and the second resistance value are the same. Generating a quasi-voltage VREF; And comparing the reference voltage VREF with the voltage VX according to the termination operation and outputting the resistance value detection signals TRIM_P <1: 2> and TRIM_N <1: 2>.

That is, when the first resistance value and the second resistance value are the same, the voltage VX of the node X to which the pull-up termination resistance means 203, 205, 207 and the pull-down termination resistance means 209, 211, 213 are connected is VDD / 2. In the step of outputting the resistance value detection signals TRIM_P <1: 2> and TRIM_N <1: 2>, the voltage comparison unit includes the reference voltage VREF of VDD / 2 and the voltage VX of the node X according to the termination operation. Compared by 303, the resistance value detection signals TRIM_P <1: 2> and TRIM_N <1: 2> according to the comparison result are output.

The resistance value adjusting units 215 and 217 are connected in parallel to the pull-up termination resistor unit 203 and the pull-down termination resistor unit 209 and are connected to the resistance value detection signals TRIM_P <1: 2> and TRIM_N <1: 2>. In response, the first and second resistance values are adjusted while being turned on and off. In more detail, the resistance values of the resistance value adjusting units 215 and 217 are adjusted according to the resistance value detecting signal, and each of the resistance value adjusting units 215 and 217 is a pull-up termination resistor unit 203 and a pull-down termination resistor unit 209. The first and second resistance values are adjusted according to the resistance values of the resistance value adjusting units 215 and 217 because they are connected in parallel with each other.

Although the present invention has been described by means of limited embodiments and drawings, the present invention is not limited thereto and is intended to be equivalent to the technical idea and claims of the present invention by those skilled in the art to which the present invention pertains. Of course, various modifications and variations are possible.

1 is a view showing a conventional on-die termination apparatus 101 and an output driver 115 together,

2 is a view showing an on die termination device according to a first embodiment of the present invention;

3 is a view showing in detail the resistance value detector 215 shown in FIG.

4 is a diagram illustrating an on-die termination device according to a second embodiment of the present invention.

Claims (15)

A termination resistor unit including a plurality of resistor units whose resistance values are adjusted in response to the termination control signal; A resistance value detector for detecting a resistance value error of the termination resistor and outputting a resistance value detection signal; And A resistance value adjusting unit connected in parallel to the termination resistor and on / off in response to the resistance value detecting signal and adjusting the resistance value On die termination device comprising a. The method of claim 1, The plurality of resistance means At least one pull-up termination resistor connected to a predetermined node to turn on / off in response to the termination control signal and perform a pull-up termination operation; And At least one pull-down termination resistor connected to the predetermined node to turn on / off in response to the termination control signal and perform a pull-down termination operation; On die termination device comprising a. 3. The method of claim 2, The resistance value detector Detecting a difference between the total resistance of the pull-up termination resistor and the total resistance of the pull-down termination resistor On die termination device. The method of claim 3, wherein The resistance value detector A reference voltage generator for generating a reference voltage equal to a voltage of the predetermined node when resistance values of the pull-up termination resistance means and the pull-down termination resistance means coincide; And A voltage comparison unit comparing the voltage of the predetermined node with the reference voltage and outputting the resistance detection signal according to a comparison result On die termination device comprising a. The method of claim 4, wherein The reference voltage generator To generate a voltage larger and smaller than the reference voltage by a predetermined value. On die termination device. The method of claim 5, The voltage comparison unit Comparing the voltage of the predetermined node with each of the plurality of voltages generated by the reference voltage generator to output the resistance value detection signal On die termination device. The method of claim 1, The resistance value adjusting unit At least one resistance means connected in parallel to each of the plurality of resistance means and on / off in response to the resistance value detection signal; On die termination device comprising a. The method of claim 1, The termination control signal is Generated in the mode register set On die termination device. An output driver for outputting data by terminating the data output node by pull-up or pull-down using a plurality of resistance means turned on / off in response to the termination control signal; A resistance value detector for detecting a resistance value error of the plurality of resistance means and outputting a resistance value detection signal; And A resistance value adjusting unit connected in parallel to the termination resistor and on / off in response to the resistance value detecting signal and adjusting the resistance value Semiconductor memory device comprising a. The method of claim 9, The resistance value detector Detecting a difference between the resistance values of the pull-up termination resistors performing the pull-up termination and the pull-down termination resistors performing the pull-down termination of the plurality of resistors; Semiconductor memory device. The method of claim 10, The resistance value detector A reference voltage generator for generating a predetermined reference voltage; And A voltage comparator for comparing the voltage of a predetermined node to which the pull-up termination resistance means and the pull-down termination resistance means are connected with the reference voltage and outputting the resistance detection signal according to a comparison result Semiconductor memory device comprising a. The method of claim 11, The predetermined reference voltage Is equal to the voltage of the predetermined node when the total resistance value of the pull-up termination resistance means and the total resistance value of the pull-down termination resistance means coincide. Semiconductor memory device. The method of claim 9, The resistance value adjusting unit At least one resistance means connected in parallel to each of the plurality of resistance means and on / off in response to the resistance value detection signal; Semiconductor memory device comprising a. Performing a pull-up termination operation on the first resistance value according to the termination control signal for impedance matching; Performing a pull-down termination operation with a second resistance value according to the termination control signal for impedance matching; Detecting a difference between the first resistance value and the second resistance value and outputting a resistance value detection signal; And Adjusting each of the first and second resistance values in response to the resistance value detection signal; On die termination control method comprising a. 15. The method of claim 14, The step of outputting the resistance value detection signal Generating a reference voltage equal to a voltage according to a termination operation when the first resistance value and the second resistance value are the same; And Comparing the reference voltage with a voltage according to the termination operation and outputting the resistance detection signal; On die termination control method comprising a.

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