Surface-Mountable Capacitors for RF Decoupling

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Solution Overview

Problem

The high cost of radio frequency (RF) devices is attributed to the use of specialized lumped element devices, particularly high-cost capacitors and inductors, which are a significant source of expense in RF devices.

Innovation Solution

The use of surface-mountable capacitors in a shunt configuration between transistors and a power supply to decouple them, reducing the need for expensive wire-bondable capacitors and minimizing parasitic inductance by placing the capacitor close to the RF cold point.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If specialized wire-bondable capacitors are used for decoupling transistors from power supply, then decoupling performance is improved, but device cost increases significantly

Engineering Contradiction:

Improvedecoupling performanceVSAvoiddevice cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces expensive wire-bondable capacitors with inexpensive surface-mountable capacitors. The surface-mountable capacitors achieve sufficient decoupling performance for the application while being significantly cheaper and easier to manufacture, directly addressing the cost issue without sacrificing essential functionality

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the mounting configuration from wire-bondable to surface-mountable, and positions the capacitor close to the RF cold point. This parameter change reduces parasitic inductance and achieves effective decoupling with a lower-cost component type, resolving the contradiction between cost and performance

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If capacitors are placed close to the RF cold point, then parasitic inductance is minimized, but device complexity increases

Engineering Contradiction:

Improveparasitic inductanceVSAvoiddevice complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent combines the decoupling capacitor placement with the existing RF cold point location in the device layout. By positioning the surface-mountable capacitor at or near the RF cold point, the design achieves minimal parasitic inductance without adding separate complex routing or additional components, thus reducing overall device complexity

Inventive Principle:

Principle #5Merging (Combining)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach significantly reduces the overall cost of RF devices while maintaining high performance by using surface-mountable capacitors instead of expensive wire-bondable capacitors, and by positioning them close to the RF cold point to minimize parasitic inductance.

Implementation Method 1

a surface-mountable capacitor, the surface-mountable capacitor coupled in a shunt configuration between the at least one transistor and a power supply to decouple the at least one transistor from a power supply

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

minimizing parasitic inductance by placing the capacitor close to the RF cold point

Methodology Applied

Scientific EffectParasitic inductance minimization: Inductor

Data Source

PatentUS9800208B2Radio frequency devices with surface-mountable capacitors for decoupling and methods thereof

Publication Date: 2017.10.24 NXP USA INC

AI summary

An embodiment of a radio-frequency (RF) device includes at least one transistor, a package, and a surface-mountable capacitor. The package contains the at least one transistor and includes at least one termination. The surface-mountable capacitor is coupled in a shunt configuration between the at least one transistor and a power supply terminal of the device to decouple the at least one transistor from a power supply.