JPH0249462A - semiconductor integrated circuit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a semiconductor integrated circuit in which circuit blocks such as an FM/AM tuner having different signal frequencies and signal levels are formed on the same semiconductor substrate.

(0) Conventional technology Electronic devices such as TV tuners and FM/AM tuners are
Since the audio signal is extracted from the F (Radio Frequency) signal, the frequency of the signal handled by each circuit block divided by function is often different. For example, an FM tuner for Japan only has an RF signal of 76 to 9
0MHz, the intermediate frequency signal is 10.7MHz, and 2
0 to 200001 (z audio signal and 20Hz to
It will handle a wide range of signals of 90MHz.

An example of the above FM/AM tuner is shown in FIG. In the figure, (1) selects an FM broadcast and mixes the received frequency signal with the oscillation frequency signal of the local oscillation circuit (2).
3) is an FM front-end circuit that converts the frequency into an intermediate frequency by mixing the intermediate frequency signal (I
FM-IF amplification circuit that amplifies and limits the amplitude of the F-fold signal and detects it to obtain an audio signal (AF-fold signal, (5)
) is a noise canceling circuit having a function such as that described in Japanese Patent Publication No. 62-21461, (6) is a multiplex circuit that demodulates L channel and R channel signals in the case of stereo broadcasting, and (7) is an AM This is an AM tuner circuit that selects broadcasting stations and outputs audio signals.

For example, in the case of FM broadcast reception, the RF multiplied signal FM is input from the antenna (8) and high-frequency amplified by the RF amplifier circuit (9).
The oscillation frequency signal output by the local oscillation circuit (2) of the front end circuit (1) is connected to the FM front end circuit (1).
By mixing in the mixing circuit (3), the FM front end circuit (1) outputs the IP multiplied signal, and the IF multiplied signal F
A composite signal is output from the FM-IF amplifier circuit (4) by detection by the detection circuit of the M-IF amplifier circuit (4), and the composite signal is output from the output terminal (1) by the multiplex circuit (6).
0) to output upper channel and R channel audio signals, respectively. Furthermore, the FM tuner circuit with such a configuration is described in, for example, the article published on December 10, 1988, "
88 Sanyo Semiconductor Data Book, Bipolar Integrated Circuits for Portable Audio Edition, page 152.

Incidentally, electronic devices in recent years are required to be more and more compact and high-performance, and accordingly, the circuit shown in FIG. 4 is being made into a single chip as much as possible. However, in the example of the FM tuner mentioned above, the FM front end circuit (1) is several tens of M
Since it handles high frequency signals of Hz, interference with other circuits is likely to occur due to unnecessary radiation.

In addition, since the weak level signal from the antenna (8) is handled, the circuit operation tends to become unstable due to interference with other circuit blocks, and in severe cases, it may oscillate.
It was extremely difficult to integrate the front-end circuit (1) into a single chip.

(c) Problems to be Solved by the Invention As described above, conventionally there has been a drawback that it is extremely difficult to integrate the FM front-end circuit (1) because circuit interference is likely to occur.

(d) Means for Solving the Problems The present invention has been made in view of the above-mentioned drawbacks, and includes first and second electronic circuit blocks that operate simultaneously, and the first and second electronic circuit blocks. In a semiconductor integrated circuit having a third electronic circuit block that does not operate simultaneously with the third electronic circuit block, the third electronic circuit block is located between the first and second block regions in which the first and second electronic circuit blocks are formed. a third block area separating the first block area and the second block area;
This problem is solved by forming a third block region in which electronic circuit blocks are formed.

(*) Effect According to the present invention, when the first and second electronic circuit blocks are operating, the third electronic circuit block is not operating; The dedicated third ground line is a line dedicated to absorption, absorbs leakage current from both the first and second electronic circuit blocks, and connects the first and second electronic circuit blocks. Prevent mutual interference. Furthermore, a third block region with high impedance is provided between the first block region and the second block region,
Mutual interference between the first electronic circuit block and the second electronic circuit block can be prevented.

(F) Example A first example of the present invention will be described below with reference to FIG. First, there are first to third electronic circuit blocks,
The first to third block regions (21), (22), (
23).

These first to third block areas (21) and (22
).

(23) is a hatched area in which, for example, an FM front end block, an FM-IF block, and an AM tuner block are formed.

The first block area (21) in which the FM front end block is formed is integrally formed in a rectangular shape in an arbitrary area of the semiconductor chip (24).
) is surrounded by a third block area (23) in which the AM tuner block is formed. Furthermore, a second block area (22) forming the FM-IF block is formed at the outer periphery of the third block area (23).

Therefore, the third block area (23) separating the first block area (21) and the second block area (22)
) is formed.

The AM tuner block formed in this third block area (23) is located in the first and second block areas (21).
), (22) are stopped when the FM front end block and FM-IF block are in operation. Therefore, the third block area (23) has a high impedance, and mutual interference between the first and second block areas (21) and (22) can be prevented.

Furthermore, the AM tuner block itself has a huge capacity. Like the cosidenser shown in Fig. 2, this consists of an N-type epitaxial JW (25), a P+-type isolation region (26), an N-type epitaxial layer (25), and a P-type semiconductor substrate (27).
). Therefore, the first block area (2
Even if high frequency noise invades the semiconductor substrate (27) from the first block area (21) and the second block area (22), the huge capacitance will This high frequency noise is
The power line (
28) and each block area (21)
, (22), high-frequency noise does not enter and interference can be prevented.

On the other hand, around the first block area (21), there is a first ground line (29) dedicated to the first electronic circuit block.
is formed, and this first ground line (29) is connected to a first ground pad GND formed around the semiconductor chip (24).

Further, a third ground line (30) dedicated to the third electronic circuit block is provided around the third block area (23).
is completely formed and extends from the second ground pad GND formed around the semiconductor chip (24). Further, at the lower end of the second block area (22), there is a second ground line (31) dedicated to the second electronic circuit block.
is extended from the second ground pad GND.

Therefore, there is a first ground line (29) between the first block area (21) and the third block area (23).
A third ground line (
30) is provided.

In addition, the first power supply line (32
) extends from the first power supply rose l''VCCI provided around the semiconductor chip (24) and supplies power to the second and third electronic circuit blocks. 2 power line and 3rd power line (
33) and (2g) extend from the second power supply pad'/CC1 provided around the semiconductor chip (24) and supply power.

Here, the first to third ground lines (29), (
31) and (30) are connected to the P+ type isolation region (26) as shown in FIG.
) can absorb leakage xi. In addition, the second ground line (31) and the third ground line (
30) extends to the second ground pad GND on each side line, so the first block area (
21) to the third ground line (30
), and this leakage current is absorbed by the second ground pad G.
It can be passed to the outside via ND.

Therefore, the second ground line (31) is free from interference due to this leakage current.

Similarly, a second power line <33> and a third power line (28) extend from the second power supply pad VCC*, and a third power line (28) extends from the first electronic circuit block.
28> is no longer applied directly to the second electronic circuit block (22).

As is clear from the above description, the most distinctive feature of the present invention is that the first block area (21) and the second block area (22) are separated by triple barriers to prevent mutual interference. The reason is that it has been prevented. These threefold barriers are as follows.

First, the first barrier is to provide a first ground line (29) exclusively for the first electronic circuit block between the first block area (21) and the third block area (22). be. Therefore, this ground line (29)
block area (21) or the second block area (2
2), it is possible to absorb the leakage current of the substrate that causes interference to the second block area (22) or the first block area (21).

The second barrier is then a third block area (23) surrounding the first block area (21). Since the first electronic circuit block, the second electronic circuit block, and the third electronic circuit block do not work at the same time, when the first electronic circuit block and the second electronic circuit block are working, The electronic circuit block 3 is stopped. Therefore, the third electronic circuit block becomes high impedance, and the first
block area (21) or the second block area (2
2) can be prevented from interfering with the second block area (22) or the first block area (21).

Further, a third barrier is formed between the second block area (22) and the third block area (22).
A third ground line (30) dedicated to the third electronic circuit block is provided between the block area (23) and the third electronic circuit block. This third ground line (30) has the same effect as the first barrier described above. In other words, when the third block area is operating, it becomes the ground line of the third electronic circuit block, and when the first and second electronic circuit blocks are operating, it becomes the ground line exclusively for sucking. Interference between the first and second electronic circuit blocks is prevented.

Next, a second embodiment will be explained using FIG. 3.

As shown in the figure, the semiconductor chip (51) includes first and second electronic circuit blocks that operate simultaneously, a third electronic circuit block that does not operate simultaneously with the first and second electronic circuit blocks, and a third electronic circuit block that operates at all times. A fourth and a fifth electronic circuit block are incorporated therein.

In FIG. 3, for example, the first to fifth electronic circuit blocks are sequentially an FM front end block, an FM-IF
block, AM tuner block, multiplex block, and bias block are formed.

Here, the FM front end block is placed at the corner of the semiconductor chip (51) because interference with other blocks is the least desirable. Here, it is integrated in the upper left corner of the four corners in a rectangular shape.

Therefore, the first block area (52) in which the first electronic circuit block is integrated is located at the corner of the semiconductor chip (51).

Next, a third block area (53) in which third electronic circuit blocks are integrated in an L shape is formed to the right and below the first block area (52).

Here, the third block area (53) is formed in an L-shape on the side of the first block area (52) that is in contact with the area where components other than the first electronic circuit block are formed.

Further, a second block area (54) in which the second electronic circuit block can be integrated is formed on the lower side of the third block area (53).

Here, a second block area (54) is formed in a region other than the first block area (52) and third block area (53).

Finally, the first to third block areas (52),
(54) and (53) are formed in the remaining area,
Fourth and fifth block regions (55) and (56) are formed in which fourth and fifth electronic circuit blocks can be integrated.

The first power supply line (57) is connected to the first power supply pad VCC.
A first ground line (58) extends from the first block area (52) and the third block area (
53) and the first ground pad GND
, further extending to supply power to the first electronic circuit block.

The second power supply line (59) extends from the second power supply pad, and the second ground line (60) is provided on the lower side of the second block area (54) and extends from the second power supply pad. It supplies power to the electronic circuit block.

The third power line (61) is connected to the second power line (
59), and the third ground line (62
) extends in parallel with the second ground line (60), extends halfway between the second block area (54) and the third block area (53), and extends in parallel with the second ground line (60). It supplies power to the electronic circuit block.

(G) As described in detail, according to the present invention, the block areas (21) and (22) are located between the first block area (21> and the second block area (22)). By providing the third block area (23) so that the electronic circuit blocks are separated from each other, firstly, it is possible to prevent the intrusion of noise that causes mutual interference.Secondly, the first and second electronic circuit blocks are separated from each other. When in operation, the third electronic circuit block is not in operation, and the impedance between the first and second block regions is increased by the third block region, further preventing noise from entering. Thirdly, the third electronic circuit block has N
type epitaxial layer (25) and P type substrate (27),
An N-type epitaxial layer (25) and a P"-type isolation region (
26), and since the third block area (23) is connected to the third power line (28), high frequency noise passing through the third block area (23) is absorbed by the third power supply line (28). Therefore, mutual interference between the first and second electronic circuit blocks can be prevented.

In addition, the first block area (21) and the third block area (23), or the second block area (22) and the third block area
A P′″ type isolation region (
By providing the first ground line (29) or third ground line (30) in ohmink contact with 2 block area (22
) to the first block region (21) can be absorbed.

Therefore, when the first electronic circuit block and the second electronic circuit block are in operation, the first ground line (29), the third block area (23) and the third ground line (28 ) can act as a barrier and prevent mutual interference.

Furthermore, when the third electronic circuit block is operating,
The third block area and the third ground line operate as separate circuit functions, and when the first and second electronic circuit blocks are operating, the third block area and the third ground line operate as separate circuits. The ground line serves as a high-impedance ground line between the first and second block areas, and serves as a ground line dedicated to absorbing leakage current from the first and second block areas, and serves two functions.

Therefore, if the first to third electronic circuit blocks are an FM front-end block, an FM-IF block, and an AM tuner block, mutual interference between the FM front-end block and the FM-1F block can be prevented, and integration into one chip becomes possible. .

[Brief explanation of the drawing]

FIG. 1 is a plan view of a semiconductor integrated circuit according to an embodiment of the present invention, FIG. 2 is a schematic cross-sectional view taken along line AA' in FIG. 1,
FIG. 3 is a plan view of a semiconductor integrated circuit according to an embodiment of the present invention, and FIG. 4 is a block diagram of an FM/AM tuner. (2i), (52)...first block area,
(22), (54)...second block area,
(23), (53)...third block area,
(24), (51)...semiconductor chip, (29)
, (5g)...first ground line, (30
), (62)...Third ground line, (3
1) , (60)...Second ground line.

Claims (8)

[Claims] (1) In a semiconductor integrated circuit having first and second electronic circuit blocks that operate simultaneously and a third electronic circuit block that does not operate simultaneously with the first and second electronic circuit blocks, The first block area and the second block area are separated between a first block area in which the first electronic circuit block is formed and a second block area in which the second electronic circuit block is formed. A semiconductor integrated circuit characterized in that a third block region is formed in which a third electronic circuit block is formed. (2) The semiconductor integrated circuit according to claim 1, wherein a first ground line dedicated to the first electronic circuit block is provided between the first block area and the third block area. (3) The semiconductor integrated circuit according to claim 1, wherein a third ground line dedicated to the third electronic circuit is provided between the second block area and the third block area. (4) The first to third electronic circuit blocks include an FM front end block, an FM-IF block, and an AM
The semiconductor integrated circuit according to claim 1, which is a tuner block. (5) In a semiconductor integrated circuit having first and second electronic circuit blocks that operate simultaneously, and a third electronic circuit block that does not operate simultaneously with the first and second electronic circuit blocks, A first block region in which one electronic circuit block is formed is provided in a corner portion of the semiconductor chip, and the first block region is provided on a side of the first block region in contact with a region in which a block other than the first electronic circuit block is formed. a third block area in which three electronic circuit blocks are formed;
A semiconductor integrated circuit further comprising: a second block region in which the second electronic circuit block is formed in a region where components other than the first and third electronic circuits are formed. (6) The semiconductor integrated circuit according to claim 5, wherein a first ground line dedicated to the first electronic circuit block is provided between the first block area and the third block area. (7) The semiconductor integrated circuit according to claim 5, wherein a third ground line dedicated to the third electronic circuit is provided between the second block area and the third block area. (8) The first to third electronic circuit blocks include an FM front end block, an FM-IF block, and an AM
6. The semiconductor integrated circuit according to claim 5, which is a tuner block.