SU1250997A1 - Method of checking integrated circuits - Google Patents

Abstract

The invention relates to a control and measuring technique. It can be used for time-controlled control of integrated circuits for operation and thermal parameters. The purpose of the invention is to expand the functionality of the method. According to the proposed method, in the course of the output and input control of the integrated microcircuit, the value of the current consumed by the integrated microcircuit is measured at the limiting operating frequency. These measurements are made in a time much shorter than the constant time (Л s: GS ate about with ω |

Description

t-case-crystal ti. As the crystal heats up, a constant current consumption is maintained by reducing the switching frequency,. At a fixed time, commensurate with L; The frequency of the generator is measured and compared to the specified minimum allowable value, obtained from the results of statistical processing. In the event that the frequency is less than the allowed one, the integrated circuit is considered unsuitable. The set value of the resulting frequency is determined as the minimum value of the resulting frequencies.

one

The invention relates to instrumentation technology and can be used for time-controlled control of integrated circuits for operation and thermal parameters.

The purpose of the invention is to expand the functionality of the method by combining in time the functional control and the thermal parameters of the integrated circuits.

FIG. 1 shows a diagram of a device implementing the method; FIG. 2 shows the dependence of the resulting clock frequency on time, and explains the method.

The device (Fig. 1), the control of integrated microcircuits 1 contains source 2 voltage, measuring sensor 3, power source 4, switch 5, reference source 6, analog adder 7, first 8 and second 9 summing resistors, operational amplifier 10 , feedback resistor 11, inverter 12, analog-to-digital converter 13, digital adder 14, first 15 and second 16 registers, subtraction unit 17 clock generator 18, frequency meter 19, function control unit 20 and control and synchronization unit 21.

The essence of the method is 1: shedding.

device for controlling integrated circuits 1 contains a voltage source 2, a power source 4, a switch 5, a reference voltage source 6, an analog adder 7, an operational amplifier 10, an inverter 12, an analog-to-digital converter 13, a digital adder 14, registers 15, 16, subtraction unit 17, clock generator 18, frequency meter 19, function control unit 20, unit 21 controlled and synchronized. 1 hp f-ly 2 ill.

Simultaneously with the functional control of the integrated circuit 1, it is controlled by the thermal resistance of the crystal-housing.

The control of thermal parameters is based on the dependence of the current consumed by the integrated microcircuit 1 on the frequency of its switching and on the temperature of the crystal. These dependences manifest themselves in CMOS integrated circuits, which in a static mode consume current in fractions of a microampere, whereas in a dynamic mode at the operating frequency

consumption reaches units and tens of milliamperes, and the current consumption depends on the crystal temperature, la (with increasing temperature the current

increases)

These features practically exclude internal heating of the microcircuits in a static mode (for example, at the input control of static parameters), which does not allow control of the thermal characteristics of the microcircuits at the input control of statistical parameters.

According to the proposed control method

in the process of output or input

the functional control of the integrated circuit 1 at the limiting operating frequency fg (0.1-10 MHz) at the time of the start of the functional control during several switching cycles (t is close to zero), until the crystal of the integrated circuit 1 has not warmed up (over time less than the time constant 7 of the crystal-case (approximately 50-100 ms), the value of the consumed by the integrated circuit 1 current is measured. Then, by decreasing the switching frequency as the crystal of the integrated circuit 1 heats up, the current consumption is kept constant.

After a fixed time t., Right T, the switching frequency of the integrated circuit 1 is measured, and the crystal-case thermal resistance is judged from this frequency, and the thermal resistance value itself is not determined.

The method is implemented using the device shown in FIG. one.

The control unit 20 together with the generator 18 of clock pulses provides functional control of the integrated circuit 1 by sending test sequences (block 20) and synchronizing (generator 18) signals to the output sequence of signals to its inputs, comparing it with the reference one and making a decision about the validity of the integrated circuit 1 (block 20).

Unit 21 provides control and synchronization of the operation of the device units, in particular, by connecting via key 5 the source 6 of the reference voltage to the source 4 of the power supply, in which the source 2 of the supply voltage generates and sets the voltage across the measuring resistor 3 on integrated circuits 1,

At the initial moment of the functional control, the consumed by integrated circuit 1 is measured for the frequency as follows: measure the voltage on measuring resistor 3 of power supply 4 with the help of adder 7, inverter 12 and ADC 13o In adder 7 s using the summing resistors 8 and 9 and the operational amplifier 10 with the resistor 11 in the feedback circuit, the output signal is proportional to the voltage difference between the outputs of the resistor 3. The inverter 12 inverts the polarity of the signal from the resistor 3 to allow subtraction

from the voltage at source 2

The resulting signal from the A / D converter 13 is stored in registers 15 and 16 of the digital adder 14 and fed to the inputs of the subtracting unit 17, which produces a control signal for the generator 18. At the beginning moment, the output signal of the subtractive unit 17 is zero. Then the register 15 is transferred to the storage mode, and the register 16 is left in the mode of receiving information from the A / D converter 13. As the crystal warms up, the current consumed by the integrated microcircuit 1 increases, and at the output of the digital adder 14 the change in current consumption, which is recorded in register 15. The difference between the codes recorded in registers 16 and 15 is generated at the output of block 17 and reduces the frequency of frequency generator 18 until the output signal of digital adder 14 decreases to zero. As a result, the constant current consumption of the microcircuit 1 is automatically maintained without changing the voltage of its power supply.

After a fixed time t (Fig. "2), the frequency of the generator 18 is measured by a frequency meter 19. The measurement time (t ,,) is specified by the control codes and synchronization task block 21.

The time t, M is chosen to be approximately equal in magnitude T to disregard the thermal constant of the body-to-medium time and to ensure sufficient accuracy of measurements, because when measured at the initial time () the crystal does not have time to heat up and the frequency cannot be measured with the required accuracy .

The resultant frequency (fpg.) Measured by frequency meter 19 of the clock pulses of the generator 18 is compared (FIG. 2) with the specified minimum allowable clock frequency frequency f previously determined for each possible value of t. The specified minimum permissible frequency value is determined from the results of statistical processing of the measurement results f for a batch of valid chips.

-cut

If fpj controlled integrated circuit is smaller, ae. I think

its worthless, otherwise suitable.

Thus, by compensating for the increase in the current consumption of the integrated circuits, as a result of heating the crystal and decreasing the operating frequency of the sync pulses, the resulting frequency of the sync pulse has been determined and, comparing it with the set one (for suitable integrated circuits), it is determined indirectly or not. validity is controlled integrally, microcircuits 1 by thermal resistance of the crystal-case, donkey, tdes.tvl In addition to controlling the operation, there is also the simultaneous control of the thermal resistance of the crystal-case, which expands the functionality of the method compared to investI-uM.

Claims (2)

Invention Formula 1, A method for controlling integrated circuits, consisting in that synchronous pulses and a sequence of testing signals are simultaneously and synchronously supplied to synchronizing signals, the input and information inputs of a controlled integrated circuit, respectively, compare the sequence of signals received on the codes of a controlled integrated circuit with a reference sequence of signals and in the case of a match obtained after 0 five 0 five about From the reference point, the controlled chip is considered suitable, and otherwise unsuitable,. characterized in that, in order to expand the functional possibilities: by combining in time the functional control of the integrated circuit with the control of thermal napaMeiJpoB, simultaneously with the comparison of the signal sequence obtained at the outputs of the controlled integrated circuit with this linear sequence of signals, the current drawn by the integrated circuit is measured the clock frequency at a fixed power supply voltage and keep it constant by decreasing the clock frequency lsov, measured resultant sequencer clock frequency after a time interval equal to the thermal time constant of crystal body after the start of their supply, the resulting frequency is compared with a predetermined and in case of exceeding predetermined frequency resulting controlled considered unusable chip, otherwise - non-defective, 2. Method of pop, 1, differing yusch and with the fact that the specified value. the resultant frequency is defined as the minimum value of the resultant frequencies measured for a representative sample from a batch of valid microcircuits. Editor L Pchelinska Compiled by V. Dvorkin Tehred V.Kadar Proofreader S.Shekmar 4406/42 Circulation 728 Subscription VNISHI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-355 Raushsk nab., d, 4/5 Production and printing company, Uzhgorod, st. Project, 4