# US 11,121,685 B2 · Operational amplifier > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,121,685 B2 - Document ID: US11121685B2 - Status: Granted - Kind: B2 - Application number: 16/640,321 - Filed: 2018-08-06 - Published: 2020-11-12 - Granted: 2021-09-14 - Earliest claimed: 2017-08-22 - Assignees: Rohm Co., Ltd. - Applicants: Rohm Co., Ltd. - Inventors: Hiroyuki Makimoto; Yusuke Yoshii; Yuki Inoue - Web page: https://patentgrep.com/patent/US11121685B2 ## CPC - H03F 3/4508: {using bipolar transistors as the active amplifying circuit (H03F3/45278 takes precedence)} - H03F 3/45475: {using IC blocks as the active amplifying circuit} - H03F 1/083: {in transistor amplifiers (H03F1/10 - H03F1/22 take precedence)} - H03F 1/26: Modifications of amplifiers to reduce influence of noise generated by amplifying elements - H03F 3/19: with semiconductor devices only - H03F 3/45085: {Long tailed pairs (H03F3/45112, H03F3/45139 take precedence)} - H03F 3/45179: {using MOSFET transistors as the active amplifying circuit (H03F3/45278 takes precedence)} - B60R 16/02: electric {constitutive elements} - H03F 2200/129: there being a feedback over the complete amplifier - H03F 2200/372: Noise reduction and elimination in amplifier - H03F 2200/451: the amplifier being a radio frequency amplifier - H03F 2203/45116: Feedback coupled to the input of the differential amplifier - H03F 2203/45528: the FBC comprising one or more passive resistors and being coupled between the LC and the IC - H03F 2203/45594: the IC comprising one or more resistors, which are not biasing resistor - H03F 2203/45601: the IC comprising one or more passive resistors by feedback - H03F 2203/45612: the IC comprising one or more input source followers as input stages in the IC - H10D 84/63: Combinations of vertical and lateral BJTs - H03F: AMPLIFIERS - B60R: VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR - H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES ## Abstract An operational amplifier 1 comprises transistors Q1 and Q2 forming an input stage, and input resistors R1 and R2 which form a filter together with parasitic capacitors C1 and C2 accompanying the transistors Q1 and Q2. Resistance values R of the resistors R1 and R2 may be set to R=1/(2π·fc·C), where C is the capacitance value of each of the parasitic capacitors C1 and C2, and fc is the target cutoff frequency of the filter. The operational amplifier 1 may also include a power supply resistor R0 which forms a filter together with a parasitic capacitor C0 accompanying a power supply line. ## Claims ### Claim 1 A semiconductor device comprising: an operational amplifier; a reference current setting portion configured to set a reference current of the operational amplifier; a power supply line configured to be laid between a power supply terminal and each of the operational amplifier and the reference current setting portion; a ground line configured to be laid between a ground terminal and each of the operational amplifier and the reference current setting portion; and a reference current setting line configured to be laid between the operational amplifier and the reference current setting portion, wherein the operational amplifier comprises: a transistor configured to form an input stage; and an input resistor configured to form a filter together with a parasitic capacitor of the transistor, wherein in plan view of the semiconductor device, the power supply line and the reference current setting line are laid one above another so as to partially overlap with each other, and wherein, in plan view of the semiconductor device, a part of the reference current setting line that overlaps with the power supply line is laid in a grid pattern. ### Claim 2 (depends on 1) The semiconductor device according to claim 1, wherein a resistance value R of the input resistor is set based on a capacitance value C of the parasitic capacitor and a target cutoff frequency fc of the filter such that R=1/(2π·fc·C). ### Claim 3 (depends on 1) The semiconductor device according to claim 1, wherein the operational amplifier further comprises a power supply resistor configured to form a filter together with a parasitic capacitor of the power supply line. ### Claim 4 (depends on 1) The semiconductor device according to claim 1, further comprising a capacitor configured to be connected between the power supply line and the reference current setting line. ### Claim 5 (depends on 4) The semiconductor device according to claim 4, wherein the capacitor is a parasitic capacitor between the power supply line and the reference current setting line. ### Claim 6 (depends on 1) The semiconductor device according to claim 1, wherein, in plan view of the semiconductor device, in a region enclosed by the reference current setting line laid in the grid pattern, a transistor is formed which functions as a reference current source of the operational amplifier. ### Claim 7 (depends on 6) The semiconductor device according to claim 6, wherein the transistor is composed of a plurality of unit transistors, and in plan view of the semiconductor device, the plurality of unit transistors are respectively formed in a plurality of regions enclosed by the reference current setting line laid in the grid pattern. ### Claim 8 (depends on 1) The semiconductor device according to claim 1, wherein, in plan view of the semiconductor device, a proportion of an area occupied by the power supply line in a region enclosed by the reference current setting line laid in the grid pattern is equal to or more than ½. ### Claim 9 (depends on 5) The semiconductor device according to claim 5, wherein the reference current setting line is laid using a first wiring layer, the power supply line is laid using a second wiring layer, the capacitor is formed in a region where the power supply line and the reference current setting line overlap with each other, with the first wiring layer and the second wiring layer as electrodes, and with an insulating layer laid between the electrodes as a dielectric body. ### Claim 10 (depends on 1) The semiconductor device according to claim 1, wherein a width of the ground line and a width of the reference current setting line are each narrower than a width of the power supply line. ### Claim 11 (depends on 1) An electronic appliance comprising the semiconductor device according to claim 1. ### Claim 12 (depends on 11) A vehicle comprising the electronic appliance according to claim 11. ### Claim 13 (depends on 1) The semiconductor device according to claim 1, further comprising a shield member configured to be inserted between the power supply line and each of another wiring and another element. ### Claim 14 A semiconductor device comprising: an operational amplifier; a reference current setting portion configured to set a reference current of the operational amplifier; a power supply line configured to be laid between a power supply terminal and each of the operational amplifier and the reference current setting portion; a ground line configured to be laid between a ground terminal and each of the operational amplifier and the reference current setting portion; and a reference current setting line configured to be laid between the operational amplifier and the reference current setting portion, wherein the operational amplifier comprises: a transistor configured to form an input stage; and an input resistor configured to form a filter together with a parasitic capacitor of the transistor, and wherein the semiconductor device further comprises a shield member configured to be inserted between the power supply line and each of another wiring and another element. ### Claim 15 (depends on 14) The semiconductor device according to claim 14, wherein the shield member is the ground line. ### Claim 16 (depends on 14) The semiconductor device according to claim 14, wherein the width of the ground line and the width of the reference current setting line are each equal to or less than half the width of the power supply line. ### Claim 17 (depends on 14) The semiconductor device according to claim 14, wherein the semiconductor device comprises, integrated therein, a plurality of channels of the operational amplifier. ### Claim 18 (depends on 17) The semiconductor device according to claim 17, wherein external terminals for a first channel are provided on a first side of a package, and external terminals for a second channel are provided on a second side of the package. ### Claim 19 (depends on 14) The semiconductor device according to claim 14, wherein, in plan view of the semiconductor device, a proportion of an area occupied by the power supply line in a region enclosed by the reference current setting line laid in the grid pattern is equal to or more than ½. ### Claim 20 (depends on 14) The semiconductor device according to claim 14, wherein a width of the ground line and a width of the reference current setting line are each narrower than a width of the power supply line.