PHYSICAL QUANTITY SENSING APPARATUS HAVING AN INTERNAL CIRCUIT, A FILTER CIRCUIT HAVING RESISTORS, POWER SUPPLY, GROUNDING, AND OUTPUT PADS, WITH THE LENGTH AND WIDTH OF WIRING BETWEEN THE OUTPUT OR POWER SUPPLY PAD AND THE INTERNAL CIRCUIT SET SO THAT THE RESISTANCE OF RESISTORS AND THE PARASITIC RESISTANCE COMPONENT OF THE WIRING SATISFY A CERTAIN RELATIONAL EXPRESSION

• US 20100109647A1
• Filed: 01/14/2010
• Published: 05/06/2010
• Est. Priority Date: 04/28/2005
• Status: Abandoned Application

• Current Assignee: Fuji Electric Device Technology Company Limited (Fuji Electric Systems Company Limited)
• Original Assignee: Fuji Electric Device Technology Company Limited (Fuji Electric Systems Company Limited)
• Inventors: UEYANAGI, Katsumichi, UEMATSU, Katsuyuki
• Application Number:
  US12/687,392
• Publication Number:
  US 20100109647A1
• Time in Patent Office: Days
• US Class Current: 324/123.R
• CPC Class Codes: G01D 3/032 affecting incoming signal, e.g. by averaging; gating undesired signals
• CPC Class Codes: G01L 19/0084 to the outside of the housing other details about the housing see G01L19/14
• CPC Class Codes: G01L 19/069 Protection against electromagnetic or electrostatic interferences
• CPC Class Codes: G01L 19/141 Monolithic housings, e.g. molded or one-piece housings
• CPC Class Codes: G01L 9/06 of piezo-resistive devices

Abstract

In a semiconductor device, in particular a physical quantity sensing apparatus, the length and the width of the wiring connecting a sensor internal circuit and an output or power supply pad are adjusted so that the total parasitic resistance components R1 parasitic on the wiring and the sum Rf of the resistance values of resistors in the filter circuit for countermeasuring against electromagnetic noises satisfy the relational expression R1/Rf×100<25. Also, the length and the width of the wiring between the output or power supply pad and the capacitor(s) and the length and the width of the wiring between the capacitor(s) and the grounding pad are adjusted so that the impedance Za caused by the parasitic resistance component Ra and the inductance component La of the wiring between the output or power supply pad and the capacitor(s), the impedance Zk caused by the parasitic resistance component Rk and the inductance component Lk of the wiring between the capacitor(s) and the grounding pad, and the impedance Zc caused by the capacitance component of the capacitor(s) always satisfy the relational expression Za+Zk<Zc in the frequency range of the electromagnetic noises to be cut. The semiconductor apparatus and the physical quantity sensing apparatus are provided with countermeasures against electromagnetic noises to meet the demand for automotive sensors.

Claims

1. A physical quantity sensing apparatus comprising:

an internal circuit comprising a physical quantity detecting element and an amplifier circuit for amplifying the signal output from the physical quantity detecting element;

a power supply pad for applying a power supply potential from the outside;

a grounding pad for applying a ground potential;

an output pad for outputting signals to the outside; and

a filter circuit for countermeasuring against electromagnetic noises, the filter circuit comprising capacitance means connected between the output or power supply pad and the grounding pad,

wherein the length and the width of wiring between the output or power supply pad and the capacitance means and the length and the width of wiring between the capacitance means and the grounding pad are set so that the impedance Za caused by the parasitic resistance component Ra and the inductance component La of the wiring between the output or power supply pad and the capacitance means, the impedance Zk caused by the parasitic resistance component Rk and the inductance component Lk of the wiring between the capacitance means and the grounding pad, and the impedance Zc caused by the capacitance component of the capacitance means always satisfy the relational expression Za+Zk<

Zc in the frequency range up to 2 GHz of the electromagnetic noises.

2. The physical quantity sensing apparatus according to claim 1, wherein the internal circuit, the filter circuit, the power supply pad, the grounding pad, and the output pad are formed in a single semiconductor chip.

3. The physical quantity sensing apparatus according to claim 1, wherein the capacitance means comprises a capacitor connected between the output pad and the ground pad.

4. The physical quantity sensing apparatus according to claim 1, wherein the capacitance means comprises a capacitor connected between the power supply pad and the ground pad.

5. The physical quantity sensing apparatus according to claim 1, wherein the frequency range is up to 1 GHz.