D/A conversion circuit, oscillator, electronic apparatus, and moving object

Patent metadata

Field	Value
Publication number	US-9515673-B2
Application number	US-201614995473-A
Country	US
Kind code	B2
Filing date	Jan 14, 2016
Priority date	Jan 19, 2015
Publication date	Dec 6, 2016
Grant date	Dec 6, 2016

Abstract

A D/A conversion circuit includes a plurality of resistors that are connected to each other in series, and a plurality of MOS transistors that are connected to terminals of the plurality of resistors, respectively. The plurality of resistors and the plurality of MOS transistors are formed on a semiconductor substrate. Each of the plurality of resistors is constituted by a resistive element and a plurality of contacts provided in the resistive element. The plurality of MOS transistors are disposed so that a plurality of virtual straight lines that pass through each of the plurality of contacts and are perpendicular to a longitudinal direction of the resistive element pass between gate electrodes of two adjacent MOS transistors, when seen in a plan view of the semiconductor substrate.

First claim

What is claimed is:

1. A D/A conversion circuit comprising:
a plurality of resistors that are connected to each other in series; and
a plurality of MOS transistors that are connected to terminals of the plurality of resistors, respectively,
wherein the plurality of resistors and the plurality of MOS transistors are formed on a semiconductor substrate,
wherein the plurality of resistors are constituted by a resistive element and a plurality of contacts provided in the resistive element, and
wherein the plurality of MOS transistors are disposed so that a plurality of virtual straight lines that pass through each of the plurality of contacts and are perpendicular to a longitudinal direction of the resistive element pass between gate electrodes of two adjacent MOS transistors, when seen in a plan view of the semiconductor substrate.

2. The D/A conversion circuit according to claim 1 , wherein each of the plurality of resistors has a recess formed on a side facing the MOS transistor, when seen in a plan view of the semiconductor substrate.

3. The D/A conversion circuit according to claim 2 , wherein each of the plurality of resistors has the recess formed along the gate electrode of the MOS transistor opposite thereto, when seen in a plan view of the semiconductor substrate.

4. The D/A conversion circuit according to claim 1 , wherein the gate electrode of the MOS transistor is formed of polysilicon.

5. The D/A conversion circuit according to claim 1 , wherein a distance between each of the plurality of resistors and the gate electrode of the MOS transistor is equal to or less than 1 μm.

6. The D/A conversion circuit according to claim 1 ,
wherein the plurality of MOS transistors are constituted by a plurality of P-channel type MOS transistors and a plurality of N-channel type MOS transistors, and
wherein, when seen in a plan view of the semiconductor substrate, each of the plurality of P-channel type MOS transistors is disposed so as to face one end parallel to the longitudinal direction of the resistive element, and
wherein each of the plurality of N-channel type MOS transistors is disposed so as to face the other end parallel to the longitudinal direction of the resistive element.

7. The D/A conversion circuit according to claim 1 ,
wherein, when seen in a plan view of the semiconductor substrate, the resistor that faces the MOS transistor has a recess formed on a side facing the MOS transistor, and
wherein the resistor that does not face the MOS transistor faces a dummy electrode different from electrodes of the plurality of MOS transistors and has a recess formed on a side facing the dummy electrode.

8. An oscillator including the D/A conversion circuit according to claim 1 .

9. An oscillator including the D/A conversion circuit according to claim 2 .

10. An oscillator including the D/A conversion circuit according to claim 3 .

11. An oscillator including the D/A conversion circuit according to claim 4 .

12. An electronic apparatus including the D/A conversion circuit according to claim 1 .

13. An electronic apparatus including the D/A conversion circuit according to claim 2 .

14. An electronic apparatus including the D/A conversion circuit according to claim 3 .

15. An electronic apparatus including the D/A conversion circuit according to claim 4 .

16. A moving object including the D/A conversion circuit according to claim 1 .

17. A moving object including the D/A conversion circuit according to claim 2 .

18. A moving object including the D/A conversion circuit according to claim 3 .

19. A moving object including the D/A conversion circuit according to claim 4 .

Assignees

• Seiko Epson Corp

Inventors

• Isozaki Shigenori

Classifications

• H10D84/85

  Complementary IGFETs, e.g. CMOS · CPC title

• H10D89/10

  Integrated device layouts · CPC title

• H10D84/811

  Combinations of field-effect devices and one or more diodes, capacitors or resistors · CPC title

• H10D64/661

  the conductor comprising a layer of silicon contacting the insulator, e.g. polysilicon having vertical doping variation (having lateral variation in the gate structure H10D64/671) · CPC title

• H10D1/47 Primary

  Resistors having no potential barriers · CPC title