Semiconductor device with bus terminating function

• US 20040080339A1
• Filed: 03/19/2003
• Published: 04/29/2004
• Est. Priority Date: 10/23/2002
• Status: Active Grant

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Kubo, Takashi
• Granted Patent: US 7,106,092 B2
• Time in Patent Office: Days
• US Class Current: 326/83
• CPC Class Codes: G06F 13/4086 Bus impedance matching, e.g. termination
• CPC Class Codes: H03K 19/0005 Modifications of input or output impedance
• CPC Class Codes: H03K 19/00315 in field-effect transistor circuits
• CPC Class Codes: H04L 25/0278 Arrangements for impedance matching
• CPC Class Codes: H04L 25/028 Arrangements specific to the transmitter end
• CPC Class Codes: H04L 25/0298 Arrangement for terminating transmission lines

Abstract

The distance between a drain contact and gate electrode in a terminating transistor, which couples a termination resistor connected to an output terminal to a power source node, is set shorter than in an output transistor, which drives an output node in accordance with an internal signal. The area of the terminating circuit is reduced while the reliability against the surge is maintained. Thus, an output circuit containing the terminating circuit that occupies a small area and is capable of transmitting a signal/data at high speed is provided.

Claims

1. A semiconductor device, comprising:

a first output transistor for driving an output node in accordance with an internal signal;

a first resistance element having one end connected to said output node; and

a first terminating transistor connected between other end of said first resistance element and a first power supply node, and selectively made conductive in accordance with an operation mode designating signal, a distance between a control electrode and a contact of one conduction terminal in said first terminating transistor being shorter than in said first output transistor.

2. The semiconductor device according to claim 1, further comprising

a second output transistor for driving, in operation, said output node complementarily to said first output transistor in accordance with a signal corresponding to said internal signal, a distance between said control electrode and said contact of one conduction terminal in said first terminating transistor being shorter than in said second output transistor.

3. The semiconductor device according to claim 1, further comprising:

a second resistance element having one end connected to said output node; and

a second terminating transistor connected between other end of said second resistance element and a second power supply node, and selectively made conductive in accordance with said operation mode designating signal, a distance between a control electrode and a contact of one conduction terminal in said second terminating transistor being shorter than in said first output transistor.

4. The semiconductor device according to claim 1, further comprising:

a second output transistor for driving, in operation, said output node complementarily to said first output transistor in accordance with a signal corresponding to said internal signal;

a second resistance element having one end connected to said output node; and

a second terminating transistor connected between other end of said second resistance element and a second power supply node, and selectively made conductive in accordance with said operating mode designating signal, a distance between a control electrode and a contact of one conduction terminal in said second terminating transistor being shorter than in the first and second output transistors.

5. The semiconductor device according to claim 1, wherein

said first resistance element is arranged further away from said output node relative to said first output transistor, and

said first resistance element and said first output transistor are coupled to said output node via a common interconnection line.

6. The semiconductor device according to claim 1, wherein

a distance between said control electrode and said contact of one conduction terminal in said first terminating transistor is set to minimum design size.