Texas Instruments

These devices consist of bus-transceiver circuits with 3-state or open-collector outputs, D-type flip-flops, and control circuitry arranged for multiplexed transmission of data directly from the data bus or from the internal storage registers. Data on the A or B bus is clocked into the registers on the low-to-high transition of the appropriate clock (CLKAB or CLKBA) input. Figure 1 illustrates the four fundamental bus-management functions that can be performed with the octal bus transceivers and registers. Output-enable () and direction-control (DIR) inputs control the transceiver functions. In the transceiver mode, data present at the high-impedance port may be stored in either or both registers. The select-control (SAB and SBA) inputs can multiplex stored and real-time (transparent mode) data. The circuitry used for select control eliminates the typical decoding glitch that occurs in a multiplexer during the transition between stored and real-time data. DIR determines which bus receives data whenis low. In the isolation mode (high), A data may be stored in one register and/or B data may be stored in the other register. When an output function is disabled, the input function is still enabled and can be used to store and transmit data. Only one of the two buses, A or B, may be driven at a time. The -1 version of the SN74ALS646A is identical to the standard version, except that the recommended maximum IOLin the -1 version is increased to 48 mA. There are no -1 versions of the SN54ALS646, SN54ALS648, or SN74ALS648A. The SN54ALS646, SN54ALS648, and SN54AS646 are characterized for operation over the full military temperature range of -55°C to 125°C. The SN74ALS646A, SN74ALS648A, SN74AS646, and SN74AS648 are characterized for operation from 0°C to 70°C. These devices consist of bus-transceiver circuits with 3-state or open-collector outputs, D-type flip-flops, and control circuitry arranged for multiplexed transmission of data directly from the data bus or from the internal storage registers. Data on the A or B bus is clocked into the registers on the low-to-high transition of the appropriate clock (CLKAB or CLKBA) input. Figure 1 illustrates the four fundamental bus-management functions that can be performed with the octal bus transceivers and registers. Output-enable () and direction-control (DIR) inputs control the transceiver functions. In the transceiver mode, data present at the high-impedance port may be stored in either or both registers. The select-control (SAB and SBA) inputs can multiplex stored and real-time (transparent mode) data. The circuitry used for select control eliminates the typical decoding glitch that occurs in a multiplexer during the transition between stored and real-time data. DIR determines which bus receives data whenis low. In the isolation mode (high), A data may be stored in one register and/or B data may be stored in the other register. When an output function is disabled, the input function is still enabled and can be used to store and transmit data. Only one of the two buses, A or B, may be driven at a time. The -1 version of the SN74ALS646A is identical to the standard version, except that the recommended maximum IOLin the -1 version is increased to 48 mA. There are no -1 versions of the SN54ALS646, SN54ALS648, or SN74ALS648A. The SN54ALS646, SN54ALS648, and SN54AS646 are characterized for operation over the full military temperature range of -55°C to 125°C. The SN74ALS646A, SN74ALS648A, SN74AS646, and SN74AS648 are characterized for operation from 0°C to 70°C.

These devices consist of bus-transceiver circuits, D-type flip-flops, and control circuitry arranged for multiplexed transmission of data directly from the data bus or from the internal storage registers. Output-enable (OEAB and OEBA\) inputs are provided to control the transceiver functions. Select-control (SAB and SBA) inputs are provided to select real-time or stored data transfer. The circuitry used for select control eliminates the typical decoding glitch that occurs in a multiplexer during the transition between stored and real-time data. A low input level selects real-time data, and a high input level selects stored data. Figure 1 illustrates the four fundamental bus-management functions that can be performed with the octal bus transceivers and registers Data on the A or B data bus, or both, can be stored in the internal D-type flip-flops by low-to-high transitions at the appropriate clock (CLKAB or CLKBA) terminals, regardless of the select- or output-control terminals. When SAB and SBA are in the real-time transfer mode, it is possible to store data without using the internal D-type flip-flops by simultaneously enabling OEAB and OEBA\. In this configuration, each output reinforces its input. When all other data sources to the two sets of bus lines are at high impedance, each set of bus lines remains at its last state. The -1 versions of the SN74ALS651A and SN74ALS652A are identical to the standard versions except that the recommended maximum IOLfor the -1 versions is increased to 48 mA. There are no -1 versions of the SN54ALS652, SN54ALS653, SN74ALS653, and SN74ALS654. These devices consist of bus-transceiver circuits, D-type flip-flops, and control circuitry arranged for multiplexed transmission of data directly from the data bus or from the internal storage registers. Output-enable (OEAB and OEBA\) inputs are provided to control the transceiver functions. Select-control (SAB and SBA) inputs are provided to select real-time or stored data transfer. The circuitry used for select control eliminates the typical decoding glitch that occurs in a multiplexer during the transition between stored and real-time data. A low input level selects real-time data, and a high input level selects stored data. Figure 1 illustrates the four fundamental bus-management functions that can be performed with the octal bus transceivers and registers Data on the A or B data bus, or both, can be stored in the internal D-type flip-flops by low-to-high transitions at the appropriate clock (CLKAB or CLKBA) terminals, regardless of the select- or output-control terminals. When SAB and SBA are in the real-time transfer mode, it is possible to store data without using the internal D-type flip-flops by simultaneously enabling OEAB and OEBA\. In this configuration, each output reinforces its input. When all other data sources to the two sets of bus lines are at high impedance, each set of bus lines remains at its last state. The -1 versions of the SN74ALS651A and SN74ALS652A are identical to the standard versions except that the recommended maximum IOLfor the -1 versions is increased to 48 mA. There are no -1 versions of the SN54ALS652, SN54ALS653, SN74ALS653, and SN74ALS654.

These devices consist of bus-transceiver circuits, D-type flip-flops, and control circuitry arranged for multiplexed transmission of data directly from the data bus or from the internal storage registers. Output-enable (OEAB and OEBA\) inputs are provided to control the transceiver functions. Select-control (SAB and SBA) inputs are provided to select real-time or stored data transfer. The circuitry used for select control eliminates the typical decoding glitch that occurs in a multiplexer during the transition between stored and real-time data. A low input level selects real-time data, and a high input level selects stored data. Figure 1 illustrates the four fundamental bus-management functions that can be performed with the octal bus transceivers and registers Data on the A or B data bus, or both, can be stored in the internal D-type flip-flops by low-to-high transitions at the appropriate clock (CLKAB or CLKBA) terminals, regardless of the select- or output-control terminals. When SAB and SBA are in the real-time transfer mode, it is possible to store data without using the internal D-type flip-flops by simultaneously enabling OEAB and OEBA\. In this configuration, each output reinforces its input. When all other data sources to the two sets of bus lines are at high impedance, each set of bus lines remains at its last state. The -1 versions of the SN74ALS651A and SN74ALS652A are identical to the standard versions except that the recommended maximum IOLfor the -1 versions is increased to 48 mA. There are no -1 versions of the SN54ALS652, SN54ALS653, SN74ALS653, and SN74ALS654. These devices consist of bus-transceiver circuits, D-type flip-flops, and control circuitry arranged for multiplexed transmission of data directly from the data bus or from the internal storage registers. Output-enable (OEAB and OEBA\) inputs are provided to control the transceiver functions. Select-control (SAB and SBA) inputs are provided to select real-time or stored data transfer. The circuitry used for select control eliminates the typical decoding glitch that occurs in a multiplexer during the transition between stored and real-time data. A low input level selects real-time data, and a high input level selects stored data. Figure 1 illustrates the four fundamental bus-management functions that can be performed with the octal bus transceivers and registers Data on the A or B data bus, or both, can be stored in the internal D-type flip-flops by low-to-high transitions at the appropriate clock (CLKAB or CLKBA) terminals, regardless of the select- or output-control terminals. When SAB and SBA are in the real-time transfer mode, it is possible to store data without using the internal D-type flip-flops by simultaneously enabling OEAB and OEBA\. In this configuration, each output reinforces its input. When all other data sources to the two sets of bus lines are at high impedance, each set of bus lines remains at its last state. The -1 versions of the SN74ALS651A and SN74ALS652A are identical to the standard versions except that the recommended maximum IOLfor the -1 versions is increased to 48 mA. There are no -1 versions of the SN54ALS652, SN54ALS653, SN74ALS653, and SN74ALS654.

These 8-bit D-type transparent latches are designed specifically for storing the contents of the input data bus, plus reading back the stored data onto the input data bus. In addition, they provide a 3-state buffer-type output and are easily utilized in bus-structured applications. While the latch enable (LE) is high, the Q outputs of the SN74ALS666 follow the data (D) inputs. The Q\ outputs of the SN74ALS667 provide the inverse of the data applied to its D inputs. The Q or Q\ output of both devices is in the high-impedance state if either output-enable (OE1\ or OE2\) input is at a high logic level. Read back is provided through the read-back control (OERB\) input. When OERB\ is taken low, the data present at the output of the data latches passes back onto the input data bus. When OERB\ is taken high, the output of the data latches is isolated from the D inputs. OERB\ does not affect the internal operation of the latches; however, caution should be exercised to avoid a bus conflict. The SN74ALS666 and SN74ALS667 are characterized for operation from 0°C to 70°C. These 8-bit D-type transparent latches are designed specifically for storing the contents of the input data bus, plus reading back the stored data onto the input data bus. In addition, they provide a 3-state buffer-type output and are easily utilized in bus-structured applications. While the latch enable (LE) is high, the Q outputs of the SN74ALS666 follow the data (D) inputs. The Q\ outputs of the SN74ALS667 provide the inverse of the data applied to its D inputs. The Q or Q\ output of both devices is in the high-impedance state if either output-enable (OE1\ or OE2\) input is at a high logic level. Read back is provided through the read-back control (OERB\) input. When OERB\ is taken low, the data present at the output of the data latches passes back onto the input data bus. When OERB\ is taken high, the output of the data latches is isolated from the D inputs. OERB\ does not affect the internal operation of the latches; however, caution should be exercised to avoid a bus conflict. The SN74ALS666 and SN74ALS667 are characterized for operation from 0°C to 70°C.

These 8-bit D-type transparent latches are designed specifically for storing the contents of the input data bus, plus reading back the stored data onto the input data bus. In addition, they provide a 3-state buffer-type output and are easily utilized in bus-structured applications. While the latch enable (LE) is high, the Q outputs of the SN74ALS666 follow the data (D) inputs. The Q\ outputs of the SN74ALS667 provide the inverse of the data applied to its D inputs. The Q or Q\ output of both devices is in the high-impedance state if either output-enable (OE1\ or OE2\) input is at a high logic level. Read back is provided through the read-back control (OERB\) input. When OERB\ is taken low, the data present at the output of the data latches passes back onto the input data bus. When OERB\ is taken high, the output of the data latches is isolated from the D inputs. OERB\ does not affect the internal operation of the latches; however, caution should be exercised to avoid a bus conflict. The SN74ALS666 and SN74ALS667 are characterized for operation from 0°C to 70°C. These 8-bit D-type transparent latches are designed specifically for storing the contents of the input data bus, plus reading back the stored data onto the input data bus. In addition, they provide a 3-state buffer-type output and are easily utilized in bus-structured applications. While the latch enable (LE) is high, the Q outputs of the SN74ALS666 follow the data (D) inputs. The Q\ outputs of the SN74ALS667 provide the inverse of the data applied to its D inputs. The Q or Q\ output of both devices is in the high-impedance state if either output-enable (OE1\ or OE2\) input is at a high logic level. Read back is provided through the read-back control (OERB\) input. When OERB\ is taken low, the data present at the output of the data latches passes back onto the input data bus. When OERB\ is taken high, the output of the data latches is isolated from the D inputs. OERB\ does not affect the internal operation of the latches; however, caution should be exercised to avoid a bus conflict. The SN74ALS666 and SN74ALS667 are characterized for operation from 0°C to 70°C.

These identity comparators perform comparisons on two 8-bit binary or BCD words and provide P = Q\ outputs. These devices have totem-pole outputs. The SN54ALS688 is characterized for operation over the full military temperature range of -55°C to 125°C. The SN74ALS688 is characterized for operation from 0°C to 70°C. These identity comparators perform comparisons on two 8-bit binary or BCD words and provide P = Q\ outputs. These devices have totem-pole outputs. The SN54ALS688 is characterized for operation over the full military temperature range of -55°C to 125°C. The SN74ALS688 is characterized for operation from 0°C to 70°C.

These devices contain two independent positive-edge-triggered D-type flip-flops. A low level at the preset () or clear () inputs sets or resets the outputs regardless of the levels of the other inputs. Whenandare inactive (high), data at the data (D) input meeting the setup-time requirements are transferred to the outputs on the positive-going edge of the clock (CLK) pulse. Clock triggering occurs at a voltage level and is not directly related to the rise time of CLK. Following the hold-time interval, data at the D input can be changed without affecting the levels at the outputs. The SN54ALS74A and SN54AS74A are characterized for operation over the full military temperature range of -55°C to 125°C. The SN74ALS74A and SN74AS74A are characterized for operation from 0°C to 70°C. These devices contain two independent positive-edge-triggered D-type flip-flops. A low level at the preset () or clear () inputs sets or resets the outputs regardless of the levels of the other inputs. Whenandare inactive (high), data at the data (D) input meeting the setup-time requirements are transferred to the outputs on the positive-going edge of the clock (CLK) pulse. Clock triggering occurs at a voltage level and is not directly related to the rise time of CLK. Following the hold-time interval, data at the D input can be changed without affecting the levels at the outputs. The SN54ALS74A and SN54AS74A are characterized for operation over the full military temperature range of -55°C to 125°C. The SN74ALS74A and SN74AS74A are characterized for operation from 0°C to 70°C.

These devices contain six independent 2-input OR drivers. They perform the Boolean functions Y = A + B orin positive logic. The SN54ALS832A and SN54AS832B are characterized for operation over the full military temperature range of -55°C to 125°C. The SN74ALS832A and SN74AS832B are characterized for operation from 0°C to 70°C. These devices contain six independent 2-input OR drivers. They perform the Boolean functions Y = A + B orin positive logic. The SN54ALS832A and SN54AS832B are characterized for operation over the full military temperature range of -55°C to 125°C. The SN74ALS832A and SN74AS832B are characterized for operation from 0°C to 70°C.