JPH02291714A - Integrating circuit - Google Patents

Abstract

PURPOSE:To set the oscillation frequency of an oscillation circuit with high accuracy by preparing the EEPROM transistors TR in relation to one or plural resistances and changing the switching states of these EEPROM TRs for control of the synthetic resistance value. CONSTITUTION:The EEPROM TR 10-12 are formed in parallel to the resistances 4-6 of an oscillation circuit 2 respectively. A frequency measuring device 15 is used for control of the oscillation frequency of the circuit 2. Then the output of a waveform generating circuit 13 and therefore the oscillation frequency of the circuit 2 is measured. In this case, all EEPROM TR 10-12 are turned off. Then these TR 10-12 are individually set in the switching states of each checking process based on the data received from a checking device 17. Then the switching states of the EEPROM TR 10-12 are selectively set so that the circuit 2 is set at a desired oscillation frequency.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an integrated circuit incorporating a so-called CR oscillation circuit. Conventional technology Conventional hybrid! In the f1 circuit, a resistor is formed on an electrically insulating substrate and trimmed using a laser beam to adjust the resistance value V&. The resistance value of the resistor thus adjusted, the capacitor, and the electric circuit connected thereto constitute a CR oscillation circuit.

Problems to be Solved by the Invention In such prior art, the oscillation frequency of the oscillation circuit is measured, data for trimming the resistor is collected, and based on this data, the resistor is actually trimmed using laser light. Then, perform a final test on the oscillation frequency. In this way, the work process is very time consuming and the productivity is poor. There is also a need to improve the performance of devices that perform trimming using laser light. Therefore, in the prior art, since trimming is performed using a laser beam, the 4'P workability is poor and time is required for this, and it is desired to simplify the process.

The purpose of the present invention is to set the oscillation frequency to a desired value with high precision.
The object of the present invention is to provide an integrated circuit with a built-in oscillation circuit that can be adjusted with simple work. Means for Solving the Problems The present invention incorporates an oscillation circuit constituted by a capacitor, a resistor, and an electric circuit connected in relation to these, the oscillation frequency of which is determined by the capacitance of the capacitor and the resistor. In an integrated circuit that depends on the resistance value of E
This is an integrated circuit characterized in that the forming resistance value can be adjusted by the switching state of the R OM transistor. According to the present invention, a plurality of resistors are provided for determining the oscillation frequency of the oscillation circuit, and an EEPROM transistor is connected in association with one or more of these resistors.

By changing the switching state of this EEPROM} transistor, the formed resistance values of the plurality of resistors can be adjusted. This makes it possible to set the oscillation frequency of the oscillation circuit with high precision. Embodiment drawings are diagrams schematically showing an integrated circuit chip according to an embodiment of the present invention. Inside the semiconductor integrated circuit thousand knob 1, there is a CR
Oscillation circuit 2 is built-in. This CR oscillation circuit 2 includes a capacitor 3, a plurality (three in this embodiment) of resistors 4, 5, 6 connected in series, and electrical circuits 7, 8, . It takes 9. These electrical circuits? ，
8.9 is an inverter. An EE P ROM is connected in parallel to the second resistor 4 to 6 of the oscillation circuit.
}Transistors 10 to 12 are formed, respectively. Capacitor 3, resistor 4-6, electric circuit 7-9 and EEPRO
The Mh transistors 10 to 12 can be manufactured using a semiconductor manufacturing process. The output of the oscillation circuit 2 is
A frequency-divided or predetermined waveform is periodically obtained by being applied to the waveform generating circuit 13, and its output is derived from the output terminal 14.

The signal from the output terminal 14 has a frequency of 1! It is measured by the L measuring device 15. The semiconductor integrated circuit chip 1 is operated by being supplied with electric power f by a DC power supply 16. The semiconductor integrated circuit nut 11 is molded with, for example, synthetic resin, and is laterally formed as an integrated circuit.

The procedure for adjusting the oscillation frequency of oscillation circuit 2 will be described. A DC power supply 16 is connected to the semiconductor integrated circuit chip 1,
This causes the semiconductor integrated circuit TIG1 to move by 4%. Using the frequency measurement device 15, the output of the waveform generation circuit 13,
Therefore, measure the oscillation frequency of oscillation circuit 2. At this time, first, in order to make all of EEPR OM 1 0 to 12 into off-state calendars, the inspection equipment r! The data is given to the semiconductor integrated circuit chip 11 from 116. These E E P R
O M 1 If all of 0 to 12 are off and the oscillation circuit 2 does not perform an oscillation operation, the semiconductor integrated circuit nap 1 is treated as a defective product. Regarding the semiconductor integrated circuit circuit 1 that performs oscillation operation, based on data from the inspection equipment 216, EEPROM} transistors 10 to
12 is individually set to the switching state of each inspection process shown in Table 1, and their EEPROM
Select and set the switching state from 0 to 12. EE
A PROM transistor is a transistor that uses MOS (metal oxide semiconductor) technology and whose switching state can be erased electrically. According to such an ellipse, the oscillation frequency of the oscillation circuit 2 can be finely adjusted using the frequency measurement device 15, and the workability is extremely good and the productivity is excellent. The trimming operation of the resistor using a laser beam, which was described in connection with the prior art, is not necessary, and the test efficiency can be improved.

Effects of the Invention As described above, according to the present invention, multiple 1! I. E E P RO M } in relation to one or more of the resistors.
transistors are provided, and their E E P R O M
By changing the switching state of the transistor and adjusting the six-element resistance value, it becomes possible to set the oscillation frequency of the oscillation circuit with high precision. Such a trimming operation achieves an excellent effect of higher productivity than the trimming operation using a laser beam described in connection with the prior art described above.

[Brief explanation of drawings]

The drawing is a diagram schematically showing the configuration of a semiconductor integrated circuit chip 1 according to an embodiment of the present invention. 1...Semiconductor integrated circuit chip, 2...CR oscillation circuit,
3... Capacitor, 4-6... Resistor, 7-9...
Electric circuit v each, 10 to 12... EEPROM transistor, 13... Waveform generation circuit, 15... Frequency measuring device, 16... DC power supply, 17... Inspection device

Claims (1)

[Claims] The oscillation circuit includes a capacitor, a resistor, and an electric circuit connected to these, and the oscillation frequency is determined by the capacitance of the capacitor and the resistance value of the resistor. The dependent integrated circuit is characterized in that a plurality of the resistors are provided, and EEPROM transistors are connected in association with these resistors, so that the combined resistance value can be adjusted by the switching state of the EEPROM transistors. integrated circuit.