Texas Instruments Corporation

Bao G Tran

Lionel S White, Jr

Joseph H Neal

James L Conner

Rohit L Bhuva

Michael J Overlaur

Tracy S Paulsen

Hugh Pryor McAdams

Jimmie D Childers

A method of testing a large integrated circuit (10) of modular design. Test equipment is connected to a dedicated testing pad section (20) for each circuit section (22, 24, 34) of each module (12, 14, 16). The circuit section under test is tested via the testing pad adjacent that circuit section. The test equipment is then stepped to the testing section for the next circuit section. When testing is completed, the testing section is then electrically isolated from the circuit sections to prevent interference with operation of the entire circuit (10).

Large integrated circuit with modulator probe structures

A large integrated circuit (10) of modular design, each module (12,14,16) having a circuit section (22,24,34) and a separate dedicated testing pad section (20). Each circuit module (12,14,16) can be individually functionally tested as an independent circuit with conventional prober equipment for defects. Each testing pad section (20) facilitates controlling the entire integrated circuit (10) so that the respective module circuit section (12,14,16) can be tested. Control circuitry (26) comprised of pass gates is provided to isolate the testing pad sections (20) from the operational portion (22,24,34) of the integrated circuit (10) when not under test. The present invention is ideally suited for large spatial light modulators, memory devices and other large sophisticated integrated circuits.

Large integrated circuit with modular probe structures

A semiconductor read/write memory device has a normal mode of operation and a test mode. The test mode allows concurrent writing to a number of cells in the cell array so that test patterns may be rapidly loaded. The cell array is split into subarrays and the column addressing circuitry is arranged to provide a maximum of spacing between the cells that are concurrently written. In this manner, pattern sensitivity tests may be run at higher speed because a number of bits at widely spaced positions in the array can be tested simultaneously.

High speed concurrent testing of dynamic read/write memory array

A register of the type used on as address counter in a dynamic RAM is tested by a method which does not require cycling through every possible value of the register contents. The counter is first loaded with a fixed value, all 1's or all 0's, and the contents checked by an AND or OR gate, producing a one-bit output which is monitored off-chip. Then, the carry feedback path to the counter register is altered, as by inverting all but the LSB, and the contents again checked, using the one-bit output via the AND or OR. In this manner, the operation of the counter is tested in three cycles.

High speed testing of integrated circuit

A semiconductor read/write memory device of the type using dynamic one-transistor storage cells employs dummy capacitors which are the same size as the storage capacitors, and these dummy capacitors are precharged to a reference voltage level less than half the supply voltage. A voltage divider sets the precharge level, but this divider is shunted by a control device initially so the dummy capacitors are quickly discharged to the reference level. A comparator with differential inputs determines when the reference level has reached the proper value, then the control device and the comparator are shut off to reduce power, and the reference level maintained by the voltage divider. The dummy capacitor precharge starts during the later part of an active cycle, so the specified cycle time can be minimized.

Dynamic memory with improved dummy cell circuitry

A semiconductor dynamic read/write memory device has serial data input/output modes, such as the so-called nibble, byte or extended nibble modes. This device employs improved address counter circuitry to access data from a selected row. An initial column address is latched when a serial mode is initiated, and the counter steps through the programmed number of bits, starting at the initial address. The number of bits used in the serial mode may be selected by metal-mask programming. To avoid a speed penalty, look-ahead circuitry initiates the set up for serial mode before the controls for this mode are detected.

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Houston, TX, United States of America

Bao G Tran