JPH04137559A - Variable resistance device in master slice lsi - Google Patents

Abstract

PURPOSE:To increase the mounting density of a printed board, by constituting a variable resistance element by utilizing the gates of transistors arranged in the internal region of a master slice LSI. CONSTITUTION:Resistance elements 3a-3d are formed by utilizing gates of transistors arranged in the internal region of a master slice LSI. Different resistance values are obtained as follows; one or more parts between terminals of two or more parts between terminals led out from both ends and the middle parts of the resistance elements 3a-3d are shorted or opened. That is, when a selection circuit 5 is opened, a resistance value of series connection of resistance elements 3a-3d of polysilicon gates is obtained. When the selection circuit 5 is shorted, a resistance value of series connection of the resistance elements 3a, 3b is obtained. Two kinds of resistance value can be obtained by the states of the selection circuit 5.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a gamma variable resistance device that allows the internal resistance value of a master slice LS Il to be changed after the chip is completed.

[Conventional technology]

One method for adjusting the clock skew between different LSI chips is to adjust the resistance value of the clock line after the LSI chip is completed.

FIG. 2 is a circuit diagram of a conventional variable resistance device for adjusting clock skew.

(lb) is a variable resistor that is split into two parts on the outside of the LSI chip for adjusting the γ clock skew, (2a), (2b)
is an LSI chip.

The following operation will be explained in detail. variable resistance (Ia),
By changing the resistance value of (lb), LSI chip (2a),
(2b) Manage the clock skew between the two.

[Problem to be solved by the invention]

Since the conventional variable resistance device is configured as described above, it is necessary to provide a variable resistance element on the printed circuit board, which increases the number of elements on the printed circuit board.

The problem is that the packaging density decreases. Also, L.S.
The problem is that the resistance value of any part within the I-chip cannot be adjusted.

The present invention was made in order to solve the above-mentioned problems, and an object of the present invention is to provide a variable resistance device in a master slice LSI that has a variable resistance element and a circuit that can select the resistance value of the variable resistance element. Means for Solving the Problems] This invention (this variable resistance device is a master slice LS
A resistor element is formed by connecting the gate of the transistor f to the internal region of I, and two or more terminals are taken out from both ends and part of the resistor element.

It has a circuit that controls short-circuiting and opening between at least l terminals.

[Effect]

The variable resistance device in this invention is a master slice LS.
A resistive element is formed using the internal region of I (tightly packed) using the gate of the transistor. Take out the resistive element from both ends and the middle and short-circuit the terminals at at least one place between two or more terminals. Or open it to obtain a different resistance value.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. 1st
In the figure, (3al, (3b), (3cL
(3d) is a resistive element using the polysilicon gate of a transistor which is located in the internal area of the master slice LSI, (4a).

(4b) and (4c') are each resistance element (3a)
, (3bl, (3c), (3d) take out T
This terminal, (5) is terminal (4a), (4b), (4c
) is a selection circuit that has the function of selecting short-circuit or open-circuit between G. When the selection circuit (5) is opened, the resistor element of 2 poly/recon gates (3&l
.

(3bl, (3c1. f3d) are connected in series to obtain one resistance value.

When the selection circuit (5) is short-circuited, the resistance elements (, (a),
(3b) are connected in series to obtain one resistance value, and by checking the state of the one selection circuit (5), two types of resistors II can be obtained.

In the above embodiment, the selection circuit 15) is used at one location.
Although a small one is shown, the selection circuit (5) may be used at more than 2a locations, and depending on the combination with the positions of the terminals (4a) to (4c) taken out from the resistive elements (3a) to (, 3d),
Variable resistance elements having various resistance values can be formed.

〔Effect of the invention〕

As described above, according to the present invention, the master slice LSI
The gate of the transistor is used to configure a variable resistance element, which is tightly packed in the internal region of the transistor.This makes it possible to increase the packaging density of the printed circuit board. This has the effect that the resistance value at the position can be changed one by one depending on the situation. Furthermore, the variable resistance device according to the present invention can be realized by only a wiring process.

This can be easily realized in a master slice LSI.

[Brief explanation of the drawing]

FIG. 1 shows a master slice LS according to an embodiment of the present invention.
FIG. 2 is a circuit diagram of a conventional variable resistance device. In the figure, (3a) to (3d) are resistance elements, (4
al to (4c) are terminals, and (5) is a selection circuit. In Figure 2, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] A resistive element formed by connecting the gates of transistors tightly arranged in the internal region of the master slice LSI;
A variable resistance device in a master slice LSI, which includes a circuit that can take out two or more terminals from both ends and the middle of the terminal and control shorting and opening between the terminals at at least one location.