| Specialty Logic | 2 | Active | |
| Universal Bus Functions | 1 | Active | |
74ABT18504Scan Test Devices With 20-Bit Universal Bus Transceivers | Specialty Logic | 2 | Active | The SN54ABT18504 and SN74ABT18504 scan test devices with 20-bit universal bus transceivers are members of the Texas Instruments SCOPETMtestability IC family. This family of devices supports IEEE Standard 1149.1-1990 boundary scan to facilitate testing of complex circuit board assemblies. Scan access to the test circuitry is accomplished via the 4-wire test access port (TAP) interface.
In the normal mode, these devices are 20-bit universal bus transceivers that combine D-type latches and D-type flip-flops to allow data flow in transparent, latched, or clocked modes. The test circuitry can be activated by the TAP to take snapshot samples of the data appearing at the device pins or to perform a self test on the boundary test cells. Activating the TAP in the normal mode does not affect the functional operation of the SCOPETMuniversal bus transceivers.
Data flow in each direction is controlled by output-enable (and), latch-enable (LEAB and LEBA), clock-enable (and), and clock (CLKAB and CLKBA) inputs. For A-to-B data flow, the device operates in the transparent mode when LEAB is high. When LEAB is low, the A-bus data is latched whileis high and/or CLKAB is held at a static low or high logic level. Otherwise, if LEAB is low andis low, A-bus data is stored on a low-to-high transition of CLKAB. Whenis low, the B outputs are active. Whenis high, the B outputs are in the high-impedance state. B-to-A data flow is similar to A-to-B data flow but uses the, LEBA,, and CLKBA inputs.
In the test mode, the normal operation of the SCOPETMuniversal bus transceivers is inhibited, and the test circuitry is enabled to observe and control the I/O boundary of the device. When enabled, the test circuitry performs boundary scan test operations according to the protocol described in IEEE Standard 1149.1-1990.
Four dedicated test pins are used to observe and control the operation of the test circuitry: test data input (TDI), test data output (TDO), test mode select (TMS), and test clock (TCK). Additionally, the test circuitry can perform other testing functions such as parallel signature analysis on data inputs and pseudo-random pattern generation from data outputs. All testing and scan operations are synchronized to the TAP interface.
Additional flexibility is provided in the test mode through the use of two boundary scan cells (BSCs) for each I/O pin. This allows independent test data to be captured and forced at either bus (A or B). A PSA/COUNT instruction is also included to ease the testing of memories and other circuits where a binary count addressing scheme is useful.
The SN54ABT18504 is characterized for operation over the full military temperature range of -55°C to 125°C. The SN74ABT18504 is characterized for operation from -40°C to 85°C.
The SN54ABT18504 and SN74ABT18504 scan test devices with 20-bit universal bus transceivers are members of the Texas Instruments SCOPETMtestability IC family. This family of devices supports IEEE Standard 1149.1-1990 boundary scan to facilitate testing of complex circuit board assemblies. Scan access to the test circuitry is accomplished via the 4-wire test access port (TAP) interface.
In the normal mode, these devices are 20-bit universal bus transceivers that combine D-type latches and D-type flip-flops to allow data flow in transparent, latched, or clocked modes. The test circuitry can be activated by the TAP to take snapshot samples of the data appearing at the device pins or to perform a self test on the boundary test cells. Activating the TAP in the normal mode does not affect the functional operation of the SCOPETMuniversal bus transceivers.
Data flow in each direction is controlled by output-enable (and), latch-enable (LEAB and LEBA), clock-enable (and), and clock (CLKAB and CLKBA) inputs. For A-to-B data flow, the device operates in the transparent mode when LEAB is high. When LEAB is low, the A-bus data is latched whileis high and/or CLKAB is held at a static low or high logic level. Otherwise, if LEAB is low andis low, A-bus data is stored on a low-to-high transition of CLKAB. Whenis low, the B outputs are active. Whenis high, the B outputs are in the high-impedance state. B-to-A data flow is similar to A-to-B data flow but uses the, LEBA,, and CLKBA inputs.
In the test mode, the normal operation of the SCOPETMuniversal bus transceivers is inhibited, and the test circuitry is enabled to observe and control the I/O boundary of the device. When enabled, the test circuitry performs boundary scan test operations according to the protocol described in IEEE Standard 1149.1-1990.
Four dedicated test pins are used to observe and control the operation of the test circuitry: test data input (TDI), test data output (TDO), test mode select (TMS), and test clock (TCK). Additionally, the test circuitry can perform other testing functions such as parallel signature analysis on data inputs and pseudo-random pattern generation from data outputs. All testing and scan operations are synchronized to the TAP interface.
Additional flexibility is provided in the test mode through the use of two boundary scan cells (BSCs) for each I/O pin. This allows independent test data to be captured and forced at either bus (A or B). A PSA/COUNT instruction is also included to ease the testing of memories and other circuits where a binary count addressing scheme is useful.
The SN54ABT18504 is characterized for operation over the full military temperature range of -55°C to 125°C. The SN74ABT18504 is characterized for operation from -40°C to 85°C. |
| Specialty Logic | 2 | Active | |
| Integrated Circuits (ICs) | 9 | Active | |
| Buffers, Drivers, Receivers, Transceivers | 5 | Active | |
| Integrated Circuits (ICs) | 10 | Active | |
74ABT2245Octal Transceivers And Line/MOS Drivers With 3-State Outputs | Buffers, Drivers, Receivers, Transceivers | 9 | Active | These octal transceivers and line drivers are designed for asynchronous communication between data buses. The devices transmit data from the A bus to the B bus or from the B bus to the A bus, depending on the logic level at the direction-control (DIR) input. The output-enable (OE\) input can be used to disable the device so the buses are effectively isolated.
The B-port outputs, which are designed to sink up to 12 mA, include equivalent 25- series resistors to reduce overshoot and undershoot.
When VCCis between 0 and 2.1 V, the device is in the high-impedance state during power up or power down. However, to ensure the high-impedance state above 2.1 V, OE\ should be tied to VCCthrough a pullup resistor; the minimum value of the resistor is determined by the current-sinking/current-sourcing capability of the driver.
The SN54ABT2245 is characterized for operation over the full military temperature range of -55°C to 125°C. The SN74ABT2245 is characterized for operation from -40°C to 85°C.
These octal transceivers and line drivers are designed for asynchronous communication between data buses. The devices transmit data from the A bus to the B bus or from the B bus to the A bus, depending on the logic level at the direction-control (DIR) input. The output-enable (OE\) input can be used to disable the device so the buses are effectively isolated.
The B-port outputs, which are designed to sink up to 12 mA, include equivalent 25- series resistors to reduce overshoot and undershoot.
When VCCis between 0 and 2.1 V, the device is in the high-impedance state during power up or power down. However, to ensure the high-impedance state above 2.1 V, OE\ should be tied to VCCthrough a pullup resistor; the minimum value of the resistor is determined by the current-sinking/current-sourcing capability of the driver.
The SN54ABT2245 is characterized for operation over the full military temperature range of -55°C to 125°C. The SN74ABT2245 is characterized for operation from -40°C to 85°C. |
74ABT2408-ch, 4.5-V to 5.5-V inverters with TTL-compatible CMOS inputs and 3-state outputs | Integrated Circuits (ICs) | 10 | Active | These octal buffers and line drivers are designed specifically to improve both the performance and density of 3-state memory address drivers, clock drivers, and bus-oriented receivers and transmitters. Together with the SN54ABT241, SN74ABT241A, SN54ABT244, and SN74ABT244A, these devices provide the choice of selected combinations of inverting and noninverting outputs, symmetrical active-low output-enable (OE)\ inputs, and complementary OE and OE\ inputs.
The SN54ABT240 and SN74ABT240A are organized as two 4-bit buffers/line drivers with separate OE\ inputs. When OE\ is low, the devices pass inverted data from the A inputs to the Y outputs. When OE\ is high, the outputs are in the high-impedance state.
This device is fully specified for partial-power-down applications using Ioff. The Ioffcircuitry disables the outputs, preventing damaging current backflow through the device when it is powered down.
To ensure the high-impedance state during power up or power down, OE\ should be tied to VCCthrough a pullup resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver.
These octal buffers and line drivers are designed specifically to improve both the performance and density of 3-state memory address drivers, clock drivers, and bus-oriented receivers and transmitters. Together with the SN54ABT241, SN74ABT241A, SN54ABT244, and SN74ABT244A, these devices provide the choice of selected combinations of inverting and noninverting outputs, symmetrical active-low output-enable (OE)\ inputs, and complementary OE and OE\ inputs.
The SN54ABT240 and SN74ABT240A are organized as two 4-bit buffers/line drivers with separate OE\ inputs. When OE\ is low, the devices pass inverted data from the A inputs to the Y outputs. When OE\ is high, the outputs are in the high-impedance state.
This device is fully specified for partial-power-down applications using Ioff. The Ioffcircuitry disables the outputs, preventing damaging current backflow through the device when it is powered down.
To ensure the high-impedance state during power up or power down, OE\ should be tied to VCCthrough a pullup resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver. |
| Buffers, Drivers, Receivers, Transceivers | 10 | Active | |
