TESTING IMPEDANCE ADJUSTMENT

• US 20160258997A1
• Filed: 03/05/2015
• Published: 09/08/2016
• Est. Priority Date: 03/05/2015
• Status: Active Grant

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Tang, Qiang, Guo, Xiaojiang, Ha, Chang Wan
• Granted Patent: US 9,912,498 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 13/4086 Bus impedance matching, e.g. termination
• CPC Class Codes: G11C 29/025 in signal lines
• CPC Class Codes: G11C 29/028 with adaption or trimming of parameters
• CPC Class Codes: G11C 29/50008 of impedance
• CPC Class Codes: G11C 5/04 Supports for storage elements , e.g. memory modules; Mounting or fixing of storage elements on such supports
• CPC Class Codes: H04L 25/0278 Arrangements for impedance matching

Abstract

Methods of operating integrated circuit devices are useful in testing impedance adjustment. Methods include connecting a node of the integrated circuit device to a first voltage node through a reference resistance and connecting the node to a second voltage node through a termination device, and comparing a voltage level at the node to a reference voltage for at least one resistance value of the termination device. When no available resistance value of the termination device generates a voltage level at the node that is deemed to match the reference voltage, the voltage level of the reference voltage may be altered, and the voltage level at the node may be compared to the altered reference voltage. When the voltage level at the node is deemed to match the altered reference voltage, the termination device may be deemed as passed. Otherwise, the termination device may be deemed as failed.

Claims

1. A method of operating an integrated circuit device, comprising:

connecting a node of the integrated circuit device to a first voltage node through a reference resistance and connecting the node to a second voltage node through a termination device of a signal driver circuit;

comparing a voltage level at the node to a reference voltage for at least one resistance value of the termination device;

determining that no available resistance value of the termination device generates a voltage level at the node that is deemed to match the reference voltage;

altering a voltage level of the reference voltage;

comparing the voltage level at the node to the altered reference voltage;

when the comparing of the voltage level at the node to the altered reference voltage is deemed a match of the voltage level at the node and the altered reference voltage, deeming the termination device as passed; and

when the comparing of the voltage level at the node to the altered reference voltage is not deemed a match of the voltage level at the node and the altered reference voltage, deeming the termination device as failed.

2. The method of claim 1, wherein altering a voltage level of the reference voltage comprises increasing the reference voltage if it is determined that no available resistance value of the termination device generates a voltage level at the node that is deemed to match the reference voltage when the resistance value of the termination device is at a highest adjustable resistance value of the termination device.

3. The method of claim 1, wherein altering a voltage level of the reference voltage comprises decreasing the reference voltage if it is determined that no available resistance value of the termination device generates a voltage level at the node that is deemed to match the reference voltage when the resistance value of the termination device is at a lowest adjustable resistance value of the termination device.

4. The method of claim 1, wherein determining that no available resistance value of the termination device generates a voltage level at the node that is deemed to match the reference voltage occurs after comparing the voltage level at the node to the reference voltage for only one resistance value of the termination device.

5. The method of claim 1, wherein determining that no available resistance value of the termination device generates a voltage level at the node that is deemed to match the reference voltage comprises determining that an only resistance value of the termination device fails to generate a voltage level at the node that is deemed to match the reference voltage.

6. The method of claim 1, further comprising:

adjusting a resistance value of the termination device; and

comparing the voltage level at the node to the reference voltage for each adjusted resistance value of the termination device.

7. The method of claim 6, wherein adjusting a resistance value of the termination device comprises incrementally adjusting the resistance value of the termination device.

8. The method of claim 7, wherein incrementally adjusting the resistance value of the termination device comprises incrementally adjusting the resistance value of the termination device from a lowest adjustable resistance value of the termination device.

9. The method of claim 1, wherein comparing a voltage level at the node to a reference voltage for at least one resistance value of the termination device comprises applying the voltage level at the node to a first input of a voltage comparator and applying the reference voltage to a second input of the voltage comparator.

10. The method of claim 9, wherein comparing of the voltage level at the node to the reference voltage is deemed a match when a logic level of an output of the voltage comparator transitions.

11. A method of operating an integrated circuit device, comprising:

connecting a node of the integrated circuit device to a first voltage node through a reference resistance and connecting the node to a second voltage node through a termination device of a signal driver circuit;

comparing a voltage level at the node to a reference voltage for at least one resistance value of the termination device;

determining that no available resistance value of the termination device generates a voltage level at the node that is deemed to match the reference voltage;

altering a voltage level of the reference voltage in response to a tolerance for the resistance value of the termination device;

comparing the voltage level at the node to the altered reference voltage;

when the comparing of the voltage level at the node to the altered reference voltage is deemed a match of the voltage level at the node and the altered reference voltage, deeming the termination device as passed; and

when the comparing of the voltage level at the node to the altered reference voltage is not deemed a match of the voltage level at the node and the altered reference voltage, deeming the termination device as failed.

12. The method of claim 11, wherein altering a voltage level of the reference voltage in response to a tolerance for the resistance value of the termination device comprises setting the voltage level of the reference voltage to a value according to the equation:

{Vhigh+Vlow*(1+x)}/(2+x)

where Vhigh is a voltage level of the second voltage node;

where Vlow is a voltage level of the first voltage node; and

where x is a positive or negative value indicative of the tolerance for the resistance value of the termination device.

13. The method of claim 12, wherein x has the negative value when it is determined that no available resistance value of the termination device generates a voltage level at the node that is deemed to match the reference voltage when the resistance value of the termination device is at a highest adjustable resistance value of the termination device.

14. The method of claim 12, wherein x has the positive value when it is determined that no available resistance value of the termination device generates a voltage level at the node that is deemed to match the reference voltage when the resistance value of the termination device is at a lowest adjustable resistance value of the termination device.

15. The method of claim 11, wherein determining that no available resistance value of the termination device generates a voltage level at the node that is deemed to match the reference voltage comprises determining that the voltage level at the node is greater than the reference voltage when the resistance value of the termination device is at a highest adjustable resistance value of the termination device.

16. The method of claim 11, wherein determining that no available resistance value of the termination device generates a voltage level at the node that is deemed to match the reference voltage comprises determining that the voltage level at the node is less than the reference voltage when the resistance value of the termination device is at a lowest adjustable resistance value of the termination device.

17. A method of operating an integrated circuit device, comprising:

connecting a node of the integrated circuit device to a first voltage node at a first voltage level through a reference resistance and connecting the node to a second voltage node at a second voltage level through a termination device of a signal driver circuit, wherein the second voltage level is greater than the first voltage level;

applying a voltage level at the node to a first input of a voltage comparator and applying a reference voltage that is half-way between the first voltage level and the second voltage level to a second input of the voltage comparator for at least one resistance value of the termination device;

determining that no available resistance value of the termination device results in a transition of a logic level of an output signal of the voltage comparator;

altering a voltage level of the reference voltage to increase the voltage level of the reference voltage in response to a tolerance for the resistance value of the termination device if the termination device is at a highest adjustable resistance value of the termination device, and to decrease the voltage level of the reference voltage in response to the tolerance for the resistance value of the termination device if the termination device is at a lowest adjustable resistance value of the termination device;

applying the voltage level at the node to the first input of the voltage comparator and applying the altered reference voltage to the second input of the voltage comparator;

deeming the termination device as passed if the logic level of the output signal of the voltage comparator transitions in response to applying the altered reference voltage to the second input of the voltage comparator; and

deeming the termination device as failed if the logic level of the output signal of the voltage comparator does not transition in response to applying the altered reference voltage to the second input of the voltage comparator.

18. The method of claim 17, wherein altering a voltage level of the reference voltage in response to a tolerance for the resistance value of the termination device comprises setting the voltage level of the reference voltage to a value according to the equation:

{Vhigh+Vlow*(1+x)}/(2+x)

where Vhigh is the second voltage level;

where Vlow is the first voltage level; and

where x is a positive or negative value indicative of the tolerance for the resistance value of the termination device.

19. The method of claim 17, wherein determining that no available resistance value of the termination device results in a transition of a logic level of an output signal of the voltage comparator comprises incrementally adjusting the resistance value from a lowest adjustable resistance value of the termination device to a highest adjustable resistance value of the termination device without transitioning the logic level of the output signal of the voltage comparator.

20. The method of claim 17, wherein determining that no available resistance value of the termination device results in a transition of a logic level of an output signal of the voltage comparator comprises determining that the logic level of the output signal of the voltage comparator indicates that the voltage level at the node is greater than or less than the reference voltage when the resistance value of the termination device is at a highest adjustable resistance value of the termination device or lowest adjustable resistance value of the termination device, respectively.