US 5,818,251 A · Apparatus and method for testing the connections between an integrated circuit and a printed circuit board

Abstract

Apparatus and method for testing the connection (i.e. solder joint) between an input/output (I/O) pin of an integrated circuit and a conductive trace of a printed circuit board (PCB). The internal circuitry of the integrated circuit is isolated from each I/O pin, and a first voltage source is coupled to each I/O pin via a respective pull-up load resistor. A tester circuit is coupled to each conductive trace of the PCB and compares the voltage V.sub.T thereon with a high threshold level (HTVL) and a low threshold level (LTVL) to test for a proper connection. Voltage V.sub.T is derived for an I/O pin under test when a resistive element, which is part of the tester circuit, is operatively coupled between the corresponding conductive trace and a second voltage source. If V.sub.T is below the LTVL or above the HTVL, the I/O pin is improperly coupled to the conductive trace. If V.sub.T is between the LTVL and HTVL, then the voltage on each of the other traces is compared to the HTVL. If the voltage level of one of the other traces not under test is below the HTVL, then the other I/O pin is electrically shorted to the I/O pin under test.

Claims6

Dependent claims

An integrated circuit comprising:

a plurality of input/output (I/O) pins;
resistive elements operatively selectably coupling said plurality of I/O pins, respectively, to a voltage source;
and a test line operatively coupled to said resistive elements;
wherein when a predetermined voltage is provided on said test line, said voltage source is electrically coupled to said plurality of I/O pins,
the integrated circuit further comprising:
internal circuit having a plurality of output ports, and
I/O buffer cells between the output ports of said internal circuitry and said I/O pins, respectively, and having a control input electrically coupled to the test line;
wherein when the predetermined voltage is provided on said test line, said output ports of said internal circuitry are substantially electrically decoupled by said I/O buffer cells from said respective I/O pins.

5 more elements

An electronic circuit comprising:

a printed circuit board having a plurality of traces;
an integrated circuit comprising:
a plurality of input/output (I/O) pins respectively soldered to said plurality of traces;
resistive elements operatively selectably coupling said plurality of I/O pins, respectively, to a voltage source;
a test line operatively coupled to the resistive elements;
internal circuitry having a plurality of output ports;
and
I/O buffer cells between the output ports of said internal circuitry and said I/O pins, respectively, and having a control input electrically coupled to said internal circuitry and to said test line;
wherein when a predetermined voltage is provided on said test line, said output ports of said internal circuitry are substantially electrically decoupled by said I/O buffer cells from said respective I/O pins and said voltage source is electrically coupled to said plurality of I/O pins.

6 more elements

Dependencies are inferred from the claim text.

Apparatus and method for testing the connections between an integrated circuit and a printed circuit board

Life of this patent

Apparatus and method for testing the connections between an integrated circuit and a printed circuit board

Life of this patent

Abstract

Claims6