SU1613978A1 - Method and apparatus for measuring thermal resistance of digital integral circuits - Google Patents

Abstract

The invention relates to a technique for measuring the parameters of integrated circuits and can be used to control the quality of digital integrated circuits based on TTL and TTLS logic elements. The aim of the invention is to improve the measurement accuracy by reducing the influence of the parasitic resistance in the power supply circuit of the microcircuits on the measurement result. The essence of the method is illustrated by the example of measuring the thermal resistance of a microcircuit containing two IS-NOT elements and parasitic resistances corresponding to the resistances of the internal common power supply lines. 2 sec. f-ly, 3 ill.

Description

The invention relates to a technique for measuring the parameters of integrated circuits and can be used to control the quality of digital integrated circuits based on TTL and TTLS logic elements (LE).

The purpose of the invention is to improve the measurement accuracy by reducing the NLI of the parasitic resistance in the power supply circuit of the microcircuits by the measurement result.

Fig about 1 shows the block diagram of the device; Fig 2 is equivalent to the scheme of LE in the implementation of the method; in fig. 3 is a diagram of the base LE.

The essence of the method is illustrated by the example of measuring the thermal resistance of a microcircuit, which contains two LE-AND-NOT and parasitic resistances corresponding to the resistances of the internal common supply rails (Fig. 2). As the voltage of the temperature-sensitive parameter, the change in voltage di, LE No. 1 on the load resistance RH is selected, which is recorded by a voltmeter PV. The heating of the microcircuit is carried out at a constant logical state of grey-. LE 2 by switching its output, which has a low logic level, through the limiting resistance Rjjrp with a positive power bus by switch S. From the basic LE diagram (Fig. 3), it can be seen that at the level of the logical unit at the output

WITH

:about

00

PE No. 1, the current consumption ij ,,, branch is on the base-emitter transition of a multi-emitter transistor - external common power bus 1, in one direction and to the emitter follower of the output stage - load resistance Cc - external common power bus 14 in another. The resistance is excluded from the current path I noT, so it is completely reduced to heating element No. 2. Current 1, type LE No. 2, when heating power is applied, will change by the amount of change in the base current of the output transistor, which is in the end state. The voltage drop & U pairs R p will change, which, due to the small value of the base current change, will be insignificant and will not exceed 5 mV when the voltage of the useful signal is l / 200 mV, which is less than 2.5% o

The device contains a power source 3, the investigated chip 2, switches 3 and 4 of the installation of voltages of a logical unit at the output of a non-heating LE and a logical zero at the output of a heating LE, a constant voltage voltmeter 5 for measuring a heat-sensitive parameter on the voltage, a voltmeter of constant voltage 6, DC milliammeter 7, switch 8, limiting resistance 9 and resistance

load 10.

The device works in the following way. „

When switching commutators. J

and 4 fix the voltage of the output of the non-heating non-heating LE and Ugw-at the output of the heating heating PE.

A constant voltage voltmeter 5 measures the voltage Ugp, x of a cold microcircuit. When the contacts of the switch 8 are closed, the microcircuit starts to warm up due to the flow of current I from the positive power bus through the milliammeter of direct current. Restrictive resistance 9, switch 8 to the output transistor LE fixed by readings of 7 ampere meter and voltmeter constant voltage 6

I 1 l - -----

(and). A constant-voltage voltmeter 5 determines the voltage increment of the temperature-sensitive parameter. According to the results

determine the thermal resistance of the chip R by the expression

p luva1-. g TKU-IpUlb, x

deLi U - the increment of the heat-sensitive voltage

parameter;

Tkk - temperature coefficient of heat-sensitive parameter; one . ufu.v - increment of the heating power was

 TJnr "TtT

THE BOWL.

Formulas

and

3 gains

1. A method for measuring the thermal resistance of digital integrated circuits, concluded that the controlled integrated circuit is supplied with voltage, the first logic element of the integrated circuit is set to a predetermined state, the heating power is measured, the output thermal parameters of the first logic element are measured , the measurement results determine the thermal resistance of the integrated circuit, which is distinguished by the fact that, in order to increase the measurement accuracy, the thermal For example, by eliminating the influence of the parasitic resistances of the integrated circuit, the first logic element of the integrated circuit is set to the state of a logical unit at the output, the output voltage of the logical unit is taken as the output temperature-sensitive parameter, the second logic elements of the integrated chip are set to output, and the amount of heating power is set by passing a current through the outputs of the second logic elements of the integral micr oshemy.

.2, A device for measuring the thermal resistance of digital integrated circuits containing a power source, a milliammeter of direct current, the first output of which is connected to a power source, two constant-voltage voltmeters, the input of the first of which is connected to the power supply bus of the integrated circuit, and the second with the output of the first logical element of the integrated microcircuit 5u.

we, to which the first BI.I is connected to the load resistor, the second output of which is connected to the common secret of the first switch, the output of which is connected to the input of the second logic element of the integrated circuit, the first input of the switch is connected to the common bus, that, in order to increase the accuracy of thermal resistance measurements by eliminating the influence of the parasitic resistances of the integrated circuit, c. he entered the second and

13478

the third switches n orpaFmMnre bHHM resistor, the second terminal of the miliampermeter through the limiting resistor and the second switch is connected to the output of the second logic element, integrated circuit, the inputs of the third switch are connected to the common bus and pin power

accordingly, the output is connected to the input of the first logic element of the integrated circuit, the second input of the first switch is connected to the power bus.

Figg

About 1

/

X

th / gz

Claims (2)

Claim 1. A method of measuring the thermal resistance of digital integrated circuits, which consists in supplying the supply voltage to a controlled integrated circuit, setting the first logical element of the integrated circuit in a predetermined state, setting the value of the heating power, measuring the output thermal parameters of the first logical element, according to the measurement results determine the thermal resistance of the integrated circuit, characterized in that · that, in order to improve the accuracy of measurements, thermal due to elimination of the influence of parasitic impedances of the integrated circuit, the first logical element of the integrated circuit is set to the state of the logical unit at the output, the voltage of the logical unit is taken as the output thermosensitive parameter, the second logical elements of the integrated circuit are set to the state of logical zero at the output, and the value of the heating power is set by passing current through the outputs of the second logical elements of the integrated circuit. • 2, A device for measuring the thermal resistance of digital integrated circuits, containing a power source, a DC milliammeter, the first output of which is connected to a power source, two DC voltmeters, the input of the first of which is connected to the power supply bus of the integrated circuit, and the input of the second to the output logiches- first element ¹ whom we integrated circuits connected to the first terminal of the load resistor, a second terminal of which is connected to the common bus of the first switch, whose output Cpd ene with input of the second NAND gate integrated circuit, the first input switch is connected to the common bus, characterized luminant I that, in order to improve the measurement accuracy of the thermal resistance by eliminating the influence of the parasitic resistances IC chip in. the second and third switches and a limiting resistor are introduced to it, the second output of a milliammeter through the limiting resistor and the second switch is connected to the output of the second logic element, integrated circuit, the inputs of the third switch are connected to the common bus and the external power supply, respectively, and the output is connected to the input of the first logical element of the integral microcircuit, the second input of the first switch is connected to the power bus. figure 1 Fig. G