Semiconductor driver circuit with signal swing balance and enhanced testing

• US 7,598,762 B2
• Filed: 10/04/2005
• Issued: 10/06/2009
• Est. Priority Date: 12/14/2004
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Byun, Gyung-Su, Kim, Kyu-Hyoun, Kim, Woo-Seop
• Primary Examiner(s): Nguyen; Ha Tran T
• Assistant Examiner(s): Chan; Emily Y
• Application Number:
  US11/243,369
• Publication Number:
  US 20060126403A1
• Time in Patent Office: 1,463 Days
• Field of Search: 324754-765, 327/334
• US Class Current: 324/764.01
• CPC Class Codes: G11C 2029/5006 Current
• CPC Class Codes: G11C 2207/105 Aspects related to pads, pins or terminals
• CPC Class Codes: G11C 29/02 Detection or location of defective auxiliary circuits, e.g. defective refresh counters
• CPC Class Codes: G11C 29/022 in I/O circuitry
• 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 7/1048 Data bus control circuits, e.g. precharging, presetting, equalising

Abstract

A semiconductor driver circuit includes impedance units for generating impedances at data pads, independently of each-other. Thus, signal swing widths of data signals generated at the data pads may be easily adjusted to be substantially equal for high operating speed. The semiconductor driver circuit also includes switching units for uncoupling at least one of the impedance units from at least one of the data pads for enhanced testing of the data pads.

Claims

1. A semiconductor driver circuit comprising:

a first impedance unit for generating a first impedance at a first data pad in response to a first control signal;

a second impedance unit for generating a second impedance at a second data pad in response to a second control signal independent of the first control signal;

wherein the first data pad outputs a first data signal, and wherein the second data pad outputs a second data signal that is complementary of the first data signal;

wherein the first and second data signals have respective voltage swings; and

means for adjusting the first and second control signals until the respective voltage swings of the first and second data signals are substantially equal.

2. The semiconductor driver circuit of claim 1, wherein the first data pad outputs a first data signal, and wherein the second data pad outputs a second data signal that is complementary to the first data signal.

3. The semiconductor driver circuit of claim 1, wherein the first impedance unit includes first transistors, each coupled in series with a respective first resistor, and wherein the first control signal determines which of the first transistors is turned on and which of the first respective resistors is coupled to the first data pad.

4. The semiconductor driver circuit of claim 3, wherein the second impedance unit includes second transistors, each coupled in series with a respective second resistor, and wherein the second control signal determines which of the second transistors is turned on and which of the second respective resistors is coupled to the second data pad.

5. The semiconductor driver circuit of claim 1, further comprising:

a first switching unit coupled between the first impedance unit and the first data pad; and

a second switching unit coupled between the second impedance unit and the second data pad,

wherein at least one of the first and second switching unit uncouples at least one of the first and second impedance units from at least one of the first and second data pads during testing.

6. The semiconductor driver circuit of claim 1, wherein the semiconductor driver circuit is formed within a semiconductor memory device.

7. A semiconductor driver circuit comprising:

a first impedance unit for generating a first impedance at a first data pad in response to a first control signal;

a second impedance unit for generating a second impedance at a second data pad in response to a second control signal independent of the first control signal;

a first switching unit coupled in series between the first impedance unit and the first data pad, wherein the first switching unit is used to couple or uncouple the first switching unit from the first data pad during testing of the semiconductor driver circuit; and

a second switching unit coupled in series between the second impedance unit and the second data pad, wherein the second switching unit is used to couple or uncouple the second switching unit from the second data pad during the testing of the semiconductor driver circuit,

wherein at least one of the first and second switching unit uncouples at least one of the first and second impedance units from at least one of the first and second data pads during the testing of the semiconductor driver circuit.

8. The semiconductor driver circuit of claim 7, wherein the semiconductor driver circuit is formed within a semiconductor memory device.

9. The semiconductor driver circuit of claim 7, wherein the first control signal affects the first impedance at the first data pad without affecting the second impedance at the second data pad, and wherein the second control signal affects the second impedance at the second data pad without affecting the first impedance at the first data pad.

10. The semiconductor driver circuit of claim 7, wherein the first data pad outputs a first data signal, and wherein the second data pad outputs a second data signal that is complementary to the first data signal.

11. The semiconductor driver circuit of claim 7, wherein the first impedance unit includes first transistors, each coupled in series with a respective first resistor, and wherein the first control signal determines which of the first transistors is turned on and which of the first respective resistors is coupled to the first data pad.

12. The semiconductor driver circuit of claim 11, wherein the second impedance unit includes second transistors, each coupled in series with a respective second resistor, and wherein the second control signal determines which of the second transistors is turned on and which of the second respective resistors is coupled to the second data pad.

13. A semiconductor device comprising:

a driver circuit including;

a first impedance unit for generating a first impedance at a first data pad in response to a first control signal; and

a second impedance unit for generating a second impedance at a second data pad in response to a second control signal independent of the first control signal;

wherein the first data pad outputs a first data signal, and wherein the second data pad outputs a second data signal;

a voltage detecting unit that compare voltage swings of the first and second data signals to generate at least one comparison result signal; and

a code converting unit, coupled to the voltage detecting unit, that adjusts the first and second control signals according to the at least one comparison result signal from the voltage detecting unit until the voltage swings of the first and second data signals are substantially equal.

14. The semiconductor device of claim 13, wherein the first impedance unit includes first transistors, each coupled in series with a respective first resistor, and wherein the first control signal determines which of the first transistors is turned on and which of the first respective resistors is coupled to the first data pad.

15. The semiconductor device of claim 14, wherein the second impedance unit includes second transistors, each coupled in series with a respective second resistor, and wherein the second control signal determines which of the second transistors is turned on and which of the second respective resistors is coupled to the second data pad.

16. The semiconductor device of claim 13, wherein the first and second data signals are complementary to each-other.

17. The semiconductor device of claim 13, wherein the semiconductor device is a semiconductor memory device.