1. An integrated circuit chip pin electromagnetic coupling energy estimation method, each side of the integrated circuit chip is respectively provided with a grounding pin and a plurality of signal pins, and the four grounding pins are rotationally symmetrical about the center of the integrated circuit chip, the method is characterized by comprising the following steps:

s1, selecting any two adjacent edges of the integrated circuit chip, reserving a signal pin between two grounding pins on the two adjacent edges, and deleting other signal pins to obtain a simplified model;

and S2, selecting the signal pin with the maximum average absorbed power from the simplified model as the maximum average absorbed power signal pin, and measuring the electromagnetic coupling energy of the pin of the integrated circuit chip by adopting the average absorbed power of the maximum average absorbed power signal pin.

2. The method according to claim 1, wherein the selecting the pin with the largest average absorbed power signal from the simplified model comprises: and calculating the average absorption power of each signal pin in the simplified model under the irradiation of random incident electromagnetic waves, selecting the maximum average absorption power and taking the corresponding signal pin as the maximum average absorption power signal pin.

3. The method according to claim 1, wherein the selecting the pin with the largest average absorbed power signal from the simplified model comprises:

s21, determining a signal pin at the middle position and a signal pin at the corner position of the simplified model;

the middle position signal pin and one grounding pin in the simplified model are separated by M signal pins, and if the number N of the signal pins in the simplified model is an odd number, M is (N-1)/2; if the number N of the signal pins in the simplified model is an even number, M is N/2 and N/2-1;

the corner position signal pin is the signal pin on the two adjacent edges which is closest to the junction of the two adjacent edges;

s22, calculating the average absorption power of the middle position signal pin and the corner position signal pin under the irradiation of random incident electromagnetic waves, selecting the maximum average absorption power and taking the corresponding signal pin as the maximum average absorption power signal pin.

4. The method according to any one of claims 1 to 3, wherein the average absorbed power is calculated as follows:

wherein, P_oAnd P_iRespectively loading Z to the outward tail end of any signal pin under the irradiation of random incident electromagnetic waves in the reverberation chamber_oAnd an inward end load Z_iUpper absorbed power, V_oAnd V_iRespectively, any signal pin is loaded with a load Z towards the outer end_oAnd an inward end load Z_iA voltage across;<P_o>、<P_i>respectively loads Z towards the outer tail end of a signal pin under the irradiation of random incident electromagnetic waves in a reverberation chamber_oAnd an inward end load Z_iThe average absorbed power of the power,<|V_o|²>、<|V_i|²>loads Z for the outward tail end of a signal pin under the irradiation of random incident electromagnetic waves in a reverberation chamber_oAnd an inward end load Z_iThe mean square value of the voltage on the surface, alpha, gamma, theta and phi are respectively the phase angle, the incident angle, the polarization angle and the azimuth angle of the incident electromagnetic wave,<>mean values at all angles of incidence, polarization and phase angles are indicated, and conjugate operation is indicated.

Background

High performance electronic systems continue to develop with ever higher demands on the degree of integration of the circuits, and modern electronic products and devices use a large number of integrated circuit chips (ICs). Electromagnetic energy coupled into an IC package can have a significant impact on the performance of internal circuitry, thereby affecting overall system performance. The evaluation of this energy level is therefore an important element in the field of electromagnetic compatibility. There is a great deal of research work and standards currently available to model, analyze, and test IC electromagnetic interference and electromagnetic radiation. However, computing the electromagnetic energy coupled into the IC package also takes up a lot of computer memory, and the computation result file also takes up a lot of storage space. The diversity of the package types, the numerous pins, and the cross-coupling between the pins due to high integration and miniaturization also complicate the research process, making it difficult to establish a suitable equivalent circuit for analysis and calculation.

Disclosure of Invention

In view of the above, the present invention provides a method for estimating electromagnetic coupling energy of an integrated circuit chip pin, which can quickly estimate the influence level of external interference on an internal circuit, thereby saving computation time and occupied memory.

In order to achieve the above object, the present invention provides a method for estimating electromagnetic coupling energy of pins of an integrated circuit chip, wherein each side of the integrated circuit chip is respectively provided with a ground pin and a plurality of signal pins, and four ground pins are rotationally symmetric with respect to the center of the integrated circuit chip, comprising the following steps:

s1, selecting any two adjacent edges of the integrated circuit chip, reserving a signal pin between two grounding pins on the two adjacent edges, and deleting other signal pins to obtain a simplified model;

and S2, selecting the signal pin with the maximum average absorbed power from the simplified model as the maximum average absorbed power signal pin, and measuring the electromagnetic coupling energy of the pin of the integrated circuit chip by adopting the average absorbed power of the maximum average absorbed power signal pin.

Further, the selecting a pin of the maximum average absorbed power signal from the simplified model specifically includes: and calculating the average absorption power of each signal pin under the irradiation of random incident electromagnetic waves, selecting the maximum average absorption power and taking the corresponding signal pin as the maximum average absorption power signal pin.

Further, the selecting a pin of the maximum average absorbed power signal from the simplified model specifically includes:

s21, determining a signal pin at the middle position and a signal pin at the corner position of the simplified model;

the middle position signal pin and one grounding pin in the simplified model are separated by M signal pins, and if the number N of the signal pins in the simplified model is an odd number, M is (N-1)/2; if the number N of the signal pins in the simplified model is an even number, M is N/2 and N/2-1;

the corner position signal pin is the signal pin on the two adjacent edges which is closest to the junction of the two adjacent edges;

s22, calculating the average absorption power of the middle position signal pin and the corner position signal pin under the irradiation of random incident electromagnetic waves, selecting the maximum average absorption power and taking the corresponding signal pin as the maximum average absorption power signal pin.

Further, the calculation formula of the average absorbed power is shown as follows:

wherein, P_oAnd P_iRespectively loading Z to the outward tail end of any signal pin under the irradiation of random incident electromagnetic waves in the reverberation chamber_oAnd an inward end load Z_iUpper absorbed power, V_oAnd V_iRespectively, any signal pin is loaded with a load Z towards the outer end_oAnd an inward end load Z_iA voltage across;<P_o>、<P_i>respectively loads Z towards the outer tail end of a signal pin under the irradiation of random incident electromagnetic waves in a reverberation chamber_oAnd an inward end load Z_iThe average absorbed power of the power,<|V_o|²＞、<|V_i|²load Z of signal pin towards outer end under irradiation of random incident electromagnetic wave in reverberation chamber_oAnd an inward end load Z_iMean square value of voltage, alpha, gamma, theta, phiIncluding the phase angle, incident angle, polarization angle and azimuth angle of the incident electromagnetic wave,<>mean values at all angles of incidence, polarization and phase angles are indicated, and conjugate operation is indicated.

Compared with the prior art, the pin electromagnetic coupling energy estimation method provided by the invention shortens a large amount of computer simulation time, saves consumed memory and also saves the storage space occupied by a simulation result file; the calculation of the coupled electromagnetic energy in the IC package is greatly simplified into the calculation of the average absorbed power by selecting a proper signal pin, so that a good reference is provided for solving the problem that a proper equivalent circuit is difficult to establish for analysis and calculation due to the cross coupling between pins caused by the large number of package pins, high integration level and miniaturization, and a simple and convenient estimation method is provided for the electromagnetic compatibility design of the integrated circuit.

Drawings

FIG. 1 is a schematic diagram of an IC package structure according to an embodiment of the present invention;

FIG. 2 is a diagram of a complete package model of an IC according to an embodiment of the present invention;

FIG. 3 is a simplified model of an IC provided by an embodiment of the present invention;

FIG. 4 is a graph of average absorbed power versus average absorbed power for signal pins numbered 1, 51, 52 in a full package model and a simplified model;

fig. 5 is a graph comparing the average absorbed power of different signal pins in a complete package model of an IC according to an embodiment of the present invention.

Reference numerals: 1. four sides grounding IC; 11. a signal pin; 111. randomly incident electromagnetic waves; 12. a ground pin; 13. an inner local ground ring; 2. a PCB; 21. a dielectric substrate; 22. and (4) a metal ground.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.

As shown in fig. 1, the LQFP 52IC used in the IC package provided by the embodiment of the present invention is a quad-grounded IC, that is, a set with only one ground pin 12 on each quad sideForming a circuit chip. The LQFP 52IC is arranged on a Printed Circuit Board (PCB), the PCB 2 for assembly comprises a dielectric substrate 21 and a metal ground 22 arranged on the back of the dielectric substrate, the dielectric substrate 21 adopts FR4 dielectric substrate, and the dielectric constant epsilon_rThickness t 4.4_s1.55mm, size 40mm x 40 mm. The four-side grounding IC is internally provided with an internal local grounding ring 13, the four-side grounding IC is provided with a plurality of grounding pins 12 and a plurality of signal pins 11, and the signal pins 11 are connected with an external circuit through microstrip lines with 115 omega characteristic impedance and connected with an internal circuit through transmission lines with 50 omega characteristic impedance.

According to the IC package shown in fig. 1, the complete package model of the IC shown in fig. 2 is built in full wave analysis software CST child SUITE 2019, and a four-side grounded IC is disposed on a PCB including a dielectric substrate 21 and a metal ground 22 disposed on the back side of the dielectric substrate. An internal local grounding ring 13 is arranged in the four-side grounding IC, a grounding pin 12 is arranged in the middle of each side, the inward tail end of the grounding pin 12 is connected with the internal local grounding ring 13, and the outward tail end of the grounding pin 12 is connected with a metal ground 22; each side is provided with a plurality of signal pins 11, the signal pins 11 are two-port networks, the outward tail end is provided with a 115 omega port, and the inward tail end is provided with a 50 omega port. The external incident electromagnetic wave excites a coupling current on the signal pin 12, and then flows into the IC along the signal pin 12, thereby being absorbed by the internal load.

Two adjacent edges are arbitrarily selected from the IC complete package model, denoted as a first edge and a second edge, signal pins between the ground pin on the first edge and the ground pin on the second edge (signal pins numbered 1-5 and 46-52) are retained, and the other signal pins are deleted, resulting in the simplified model shown in fig. 3. In the simplified model, the number of signal pins N is 12. The number is one fourth of the number of signal pins in the complete model.

In full-wave analysis software CST STUDIO SUITE 2019, 64 plane waves are incident into an analysis model based on a Gauss-Legendre Quadrature method, and simulation is carried out. The simulation hardware conditions are as follows: the CPU adopts Intel Core i7-8^thGen @2.20GHz and RAM 64.0 GB.

Based on the above conditions, the complete package model and the simplified model are simulated, the absorption power of each signal pin in the two models under the irradiation of 64 incident plane waves is obtained respectively, and the calculation time, the peak occupation memory and the size of the calculation result file are shown in table 1.

TABLE 1 complete model and simplified model in CST simulation calculation time, peak occupied memory and calculation result file size

Model (model)	Calculating time	Peak memory usage	Calculating a result file size
				Complete model	5h7m59s	383652kB	3520MB
Simplified model	2h5m16s	176936kB	932MB

As can be seen from Table 1, compared with the complete model, the simplified model occupies less time and memory and the calculation result file is smaller when the absorbed power is analyzed and calculated.

Finding a middle position signal pin and a corner position signal pin in the simplified model shown in fig. 3;

the signal pin at the middle position is separated from one grounding pin by M signal pins, and if the number N of the signal pins in the simplified model is an odd number, M is (N-1)/2; if the number N of the signal pins in the simplified model is an even number, M is N/2 and N/2-1;

in the simplified model of the embodiment of the present invention, the number N of signal pins is 12, and is an even number, then according to the formula, M is 6 and 5, starting from the ground pin numbered 6, the signal pins are separated by 5 and 6 signal pins, and the signal pins numbered 52 and 51 are selected as the middle position signal pins.

Then in a simplified model of an embodiment of the present invention, signal pins numbered 1 and 52 are selected as corner position signal pins.

The average absorption power of the middle position signal pin and the corner position signal pin of the simplified model in the reverberation chamber under the irradiation of the random incident electromagnetic wave is calculated, the maximum average absorption power is selected, and the corresponding signal pin is used as the maximum average absorption power signal pin.

The average absorbed power is calculated as follows:

wherein, P_oAnd P_iRespectively loading Z to the outward tail end of any signal pin under the irradiation of random incident electromagnetic waves in the reverberation chamber_oAnd an inward end load Z_iUpper absorbed power, V_oAnd V_iRespectively, any signal pin is loaded with a load Z towards the outer end_oAnd an inward end load Z_iA voltage across;<P_o>、<P_i>respectively loads Z towards the outer tail end of a signal pin under the irradiation of random incident electromagnetic waves in a reverberation chamber_oAnd an inward end load Z_iThe average absorbed power of the power,<|V_o|²＞、<|V_i|²load Z of signal pin towards outer end under irradiation of random incident electromagnetic wave in reverberation chamber_oAnd an inward end load Z_iThe mean square value of the voltage on the surface, alpha, gamma, theta and phi are respectively the phase angle, the incident angle, the polarization angle and the azimuth angle of the incident electromagnetic wave,<>mean values at all angles of incidence, polarization and phase angles are indicated, and conjugate operation is indicated. This embodiment only analyzes the coupling energy into the internal circuit, so the average absorbed power calculation uses the inward end load Z_iVoltage V on_i。

The average absorbed power under random incident electromagnetic wave illumination for signal pins numbered 1, 51 and 52 was calculated in the simplified model and the complete package model, respectively, as shown in fig. 4 for the comparison graph. As can be seen from fig. 4, in the frequency range below 6GHz, the matching degree of the average absorbed power in the simplified model and the average absorbed power in the complete encapsulation model is higher, and is about 6dB higher than that in the complete model only at 7 GHz. In addition, fig. 5 again analyzes the average absorbed power of pins 1 and 46-52 in the complete package model, and it can be seen that the farther from the ground pin (12), the more the absorbed power is, i.e. the absorbed power of pin 1 and pin 52 is the largest, and the two are equivalent. From an EMC evaluation point of view, the maximum coupling into the IC should be considered, and this value can be quickly calculated from a simplified model as an estimate of the EMC coupling energy.

Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.