Integrated circuit

Details Integrated circuit Integrated circuit

2000-10-31

2004-06-08

Chin, Vivian (Department: 2682)

Telecommunications

Receiver or analog modulated signal frequency converter

Frequency modifying or conversion

C327S203000, C327S211000, C327S215000, C327S218000

Reexamination Certificate

active

06748205

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an integrated circuit and an evaluation method for the integrated circuit. More particularly, the invention relates to an integrated circuit having a driver circuit for outputting a high-speed signal to the outside or a receiver circuit for receiving a high-speed signal from the outside, and to an evaluation method for the integrated circuit.
2. Description of Related Art
Signal transmission between integrated circuits is in a tendency toward higher-speed transmission along with the increase in the amount of information (data) to be transmitted. In addition, serial conversion transmission is tried to inhibit an increase in the number of transmission lines and the number of pins in an integrated circuit, and, therefore, the tendency toward higher-speed transmission is further accellerated.
FIG. 1
illustrates a typical example of configuration of small-signal differential transmission based on a conventional integrated circuit, which copes with high-speed signal transmission of 1 Gbps (giga-bits/second). High-speed signal transmission is accomplished by a sending-side integrated circuit
8
including a driver circuit
2
, a transmission line
5
, a terminal resistor R
0
, and a receiving-side integrated circuit
9
including a receiver circuit
6
.
Data S
1
to be transmitted is converted into a differential signal by a differentiating circuit composed of inverters B
1
to B
9
in the driver circuit
2
. A positive-polarity signal of the differential signal is inputted to the gate of a CMOS (complementary metal-oxide semiconductor) transistor M
1
, and a negative-polarity signal of the differential signal is inputted the gate of a CMOS transistor M
2
. The CMOS transistors M
1
and M
2
are source-coupled to each other, and a current I
1
is supplied to the sources of the CMOS transistors M
1
and M
2
. Resistors R
1
and R
2
are connected between the drains of the CMOS transistors M
1
and M
2
and a power supply VCC, respectively. The drains of the CMOS transistors M
2
and M
1
are connected to pins P
1
and N
1
of the integrated circuit
8
, respectively, and high-speed signals (P
1
/N
1
) are outputted from the integrated circuit
8
via the pins P
1
and N
1
.
The transmission line
5
is connected to the aforementioned pins P
1
and N
1
. The receiving side of the transmission line
5
ends with the terminal resistor R
0
, and the signals (P
1
/N
1
) to be transmitted are connected to pins P
4
and N
4
of the receiving-side integrated circuit
9
.
The signals (P
4
/N
4
) having passed through the pins P
4
and N
4
are inputted to the gates of CMOS transistors M
5
and M
6
in the receiver circuit
6
, respectively. The CMOS transistors M
5
and M
6
are source-coupled to each other, and a current I
3
is supplied to the sources of the CMOS transistors M
5
and M
6
. Resistors R
5
and R
6
are connected between the drains of the CMOS transistors MS and M
6
and a power supply VCC, respectively. Differential receiving signals are obtained at the drains of the CMOS transistors MS and M
6
. The differential receiving signals are outputted, as signals P
5
and N
5
, to a signal processing circuit (not shown) in the integrated circuit
9
at such a voltage of about 0.5 Vpp as to facilitate handling in the CMOS transistor circuit.
A twisted-pair transmission line available at a relatively low cost is commonly used for the aforementioned transmission line
5
. The characteristic impedance between lines of the twisted-pair transmission line is about 100 &OHgr;. For the purpose of ensuring matching, the above-mentioned resistors R
1
and R
2
are set to 50 &OHgr;, and the above-mentioned resistor R
0
is set to 100 &OHgr;. Further, since a transmission amplitude of about 0.3 Vpp is used, the current I
1
is set to about 12 mA.
However, the conventional integrated circuit coping with high-speed signal transmission as described above has the following problems to be solved.
In order to confirm the transmission quality of a high-speed signal of 1 Gbps, the user of a particular integrated circuit is required to satisfy very difficult measuring conditions including the measuring device and probing. The particular integrated circuit must be guaranteed for accurate actions. For this purpose, the evaluation of the sending-side integrated circuit
8
and the receiving-side integrated circuit
9
in mass production thereof should be carried out under strict actual operating conditions. For example, the measurement of changes in data at intervals of 1 ns (nano-second) requires a high-accuracy measuring device under 100 ps (pico-second). An IC tester satisfying this function is expensive, so that IC shipping inspections have increased the cost of integrated circuits.
BRIEF SUMMARY OF THE INVENTION
It is an object of the present invention to provide an integrated circuit performing the sending and receiving of high-speed signals and an evaluation method therefor, which permit the achievement of simplified IC evaluation and the prevention of a cost increase of integrated circuits.
It is another object of the invention to provide an integrated circuit and an evaluation method therefor, which enable a user of integrated circuits to conduct stable and high-accuracy measurement without the need for an expensive measuring device and difficult probing, and in addition, make it possible for the user of integrated circuits to easily perform the optimization of a transmission line and a terminal resistor.
To attain the above objects of the invention, in accordance an aspect of the invention, there is provided an integrated circuit, which comprises a driver circuit for outputting a signal outside, a receiver circuit for receiving a signal from outside, and a time-axis expanding circuit for time-axis-expanding an output signal of the receiver circuit.
In accordance with another aspect of the invention, there is provided an integrated circuit, which comprises a receiver circuit for receiving a signal from outside, and a time-axis expanding circuit for time-axis-expanding an output signal of the receiver circuit.
In accordance with a further aspect of the invention, there is provided an evaluation method of evaluating a sending-side integrated circuit, the evaluation method comprising the steps of preparing an inspected integrated circuit including a first driver circuit for outputting a signal outside, a first receiver circuit for receiving a signal from outside, and a first time-axis expanding circuit for time-axis-expanding an output signal of the first receiver circuit, and an inspecting integrated circuit including a second driver circuit having the same configuration as that of the first driver circuit, a second receiver circuit having the same configuration as that of the first receiver circuit, and a second time-axis expanding circuit having the same configuration as that of the first time-axis expanding circuit, connecting the first driver circuit of the inspected integrated circuit to the second receiver circuit of the inspecting integrated circuit by a transmission line and a terminal resistor, inputting a signal to the first driver circuit of the inspected integrated circuit, and measuring a time-axis-expanded signal outputted from the second time-axis expanding circuit of the inspecting integrated circuit, on the basis of a measuring clock signal having a predetermined period, with a counter.
In accordance with a still further aspect of the invention, there is provided an evaluation method of evaluating a receiving-side integrated circuit, the evaluation method comprising the steps of preparing a driver circuit of an integrated circuit for outputting a signal outside, and an inspected integrated circuit including a receiver circuit for receiving a signal from outside, and a time-axis expanding circuit for time-axis-expanding an output signal of the receiver circuit, connecting the driver circuit to the receiver circuit of the inspected integrated circuit by a transmission line and a terminal resistor, i

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