Texas Instruments

The ’HC157, ’HCT157, ’HC158, and ’HCT158 are quad 2-input multiplexers which select four bits of data from two sources under the control of a common Select input (S). The Enable input (E\) is active Low. When (E\) is High, all of the outputs in the 158, the inverting type, (1Y\-4Y\) are forced High and in the 157, the non-inverting type, all of the outputs (1Y\-4Y\) are forced Low, regardless of all other input conditions. Moving data from two groups of registers to four common output busses is a common use of these devices. The state of the Select input determines the particular register from which the data comes. They can also be used as function generators. The ’HC157, ’HCT157, ’HC158, and ’HCT158 are quad 2-input multiplexers which select four bits of data from two sources under the control of a common Select input (S). The Enable input (E\) is active Low. When (E\) is High, all of the outputs in the 158, the inverting type, (1Y\-4Y\) are forced High and in the 157, the non-inverting type, all of the outputs (1Y\-4Y\) are forced Low, regardless of all other input conditions. Moving data from two groups of registers to four common output busses is a common use of these devices. The state of the Select input determines the particular register from which the data comes. They can also be used as function generators.

The ’HC164 and ’HCT164 are 8-bit, serial-in, parallel-out, shift registers with asynchronous reset. Data is shifted on the positive edge of Clock (CLK). A LOW on the RESET (CLR) pin resets the shift register and all outputs go to the LOW state regardless of the input conditions. Two Serial Data inputs (A and B) are provided, either one can be used as a data enable control. The ’HC164 and ’HCT164 are 8-bit, serial-in, parallel-out, shift registers with asynchronous reset. Data is shifted on the positive edge of Clock (CLK). A LOW on the RESET (CLR) pin resets the shift register and all outputs go to the LOW state regardless of the input conditions. Two Serial Data inputs (A and B) are provided, either one can be used as a data enable control.

The ’HC174 and ’HCT174 are edge triggered flip-flops which utilize silicon gate CMOS circuitry to implement D-type flip-flops. They possess low power and speeds comparable to low power Schottky TTL circuits. The devices contain six master-slave flip-flops with a common clock and common reset. Data on the D input having the specified setup and hold times is transferred to the Q output on the low to high transition of the CLOCK input. The MR\ input, when low, sets all outputs to a low state. Each output can drive ten low power Schottky TTL equivalent loads. The ’HCT174 is functional as well as, pin compatible to the ’LS174. The ’HC174 and ’HCT174 are edge triggered flip-flops which utilize silicon gate CMOS circuitry to implement D-type flip-flops. They possess low power and speeds comparable to low power Schottky TTL circuits. The devices contain six master-slave flip-flops with a common clock and common reset. Data on the D input having the specified setup and hold times is transferred to the Q output on the low to high transition of the CLOCK input. The MR\ input, when low, sets all outputs to a low state. Each output can drive ten low power Schottky TTL equivalent loads. The ’HCT174 is functional as well as, pin compatible to the ’LS174.

The ’HC175 and ’HCT175 are high speed Quad D-type Flip-Flops with individual D-inputs and Q, Q\ complementary outputs. The devices are fabricated using silicon gate CMOS technology. They have the low power consumption advantage of standard CMOS ICs and the ability to drive 10 LSTTL devices. Information at the D input is transferred to the Q, Q\ outputs on the positive going edge of the clock pulse. All four Flip-Flops are controlled by a common clock (CP) and a common reset (MR\). Resetting is accomplished by a low voltage level independent of the clock. All four Q outputs are reset to a logic 0 and all four Q\ outputs to a logic 1. The ’HC175 and ’HCT175 are high speed Quad D-type Flip-Flops with individual D-inputs and Q, Q\ complementary outputs. The devices are fabricated using silicon gate CMOS technology. They have the low power consumption advantage of standard CMOS ICs and the ability to drive 10 LSTTL devices. Information at the D input is transferred to the Q, Q\ outputs on the positive going edge of the clock pulse. All four Flip-Flops are controlled by a common clock (CP) and a common reset (MR\). Resetting is accomplished by a low voltage level independent of the clock. All four Q outputs are reset to a logic 0 and all four Q\ outputs to a logic 1.

The CD54/74HC190 are asynchronously presettable BCD decade counters, whereas the CD54/74HC191 and CD54/74HCT191 are asynchronously presettable binary counters. Presetting the counter to the number on preset data inputs (A–D) is accomplished by a low asynchronous parallel load (LOAD)\ input. Counting occurs when LOAD\ is high, count enable (CTEN)\ is low, and the down/up (D/U) input is either high for down counting or low for up counting. The counter is decremented or incremented synchronously with the low-to-high transition of the clock. When an overflow or underflow of the counter occurs, the MAX/MIN output, which is low during counting, goes high and remains high for one clock cycle. This output can be used for look-ahead carry in high-speed cascading (see Figure 1). The MAX/MIN output also initiates the ripple clock (RCO)\ output, which is normally high, goes low and remains low for the low-level portion of the clock pulse. These counters can be cascaded using RCO\ (see Figure 2). If a decade counter is preset to an illegal state or assumes an illegal state when power is applied, it returns to the normal sequence in one or two counts, as shown in the state diagrams (see Figure 3). The CD54/74HC190 are asynchronously presettable BCD decade counters, whereas the CD54/74HC191 and CD54/74HCT191 are asynchronously presettable binary counters. Presetting the counter to the number on preset data inputs (A–D) is accomplished by a low asynchronous parallel load (LOAD)\ input. Counting occurs when LOAD\ is high, count enable (CTEN)\ is low, and the down/up (D/U) input is either high for down counting or low for up counting. The counter is decremented or incremented synchronously with the low-to-high transition of the clock. When an overflow or underflow of the counter occurs, the MAX/MIN output, which is low during counting, goes high and remains high for one clock cycle. This output can be used for look-ahead carry in high-speed cascading (see Figure 1). The MAX/MIN output also initiates the ripple clock (RCO)\ output, which is normally high, goes low and remains low for the low-level portion of the clock pulse. These counters can be cascaded using RCO\ (see Figure 2). If a decade counter is preset to an illegal state or assumes an illegal state when power is applied, it returns to the normal sequence in one or two counts, as shown in the state diagrams (see Figure 3).

The CD54/74HC190 are asynchronously presettable BCD decade counters, whereas the CD54/74HC191 and CD54/74HCT191 are asynchronously presettable binary counters. Presetting the counter to the number on preset data inputs (A–D) is accomplished by a low asynchronous parallel load (LOAD)\ input. Counting occurs when LOAD\ is high, count enable (CTEN)\ is low, and the down/up (D/U) input is either high for down counting or low for up counting. The counter is decremented or incremented synchronously with the low-to-high transition of the clock. When an overflow or underflow of the counter occurs, the MAX/MIN output, which is low during counting, goes high and remains high for one clock cycle. This output can be used for look-ahead carry in high-speed cascading (see Figure 1). The MAX/MIN output also initiates the ripple clock (RCO)\ output, which is normally high, goes low and remains low for the low-level portion of the clock pulse. These counters can be cascaded using RCO\ (see Figure 2). If a decade counter is preset to an illegal state or assumes an illegal state when power is applied, it returns to the normal sequence in one or two counts, as shown in the state diagrams (see Figure 3). The CD54/74HC190 are asynchronously presettable BCD decade counters, whereas the CD54/74HC191 and CD54/74HCT191 are asynchronously presettable binary counters. Presetting the counter to the number on preset data inputs (A–D) is accomplished by a low asynchronous parallel load (LOAD)\ input. Counting occurs when LOAD\ is high, count enable (CTEN)\ is low, and the down/up (D/U) input is either high for down counting or low for up counting. The counter is decremented or incremented synchronously with the low-to-high transition of the clock. When an overflow or underflow of the counter occurs, the MAX/MIN output, which is low during counting, goes high and remains high for one clock cycle. This output can be used for look-ahead carry in high-speed cascading (see Figure 1). The MAX/MIN output also initiates the ripple clock (RCO)\ output, which is normally high, goes low and remains low for the low-level portion of the clock pulse. These counters can be cascaded using RCO\ (see Figure 2). If a decade counter is preset to an illegal state or assumes an illegal state when power is applied, it returns to the normal sequence in one or two counts, as shown in the state diagrams (see Figure 3).

The ’HC192, ’HC193 and ’HCT193 are asynchronously presettable BCD Decade and Binary Up/Down synchronous counters, respectively. Presetting the counter to the number on the preset data inputs (P0-P3) is accomplished by a LOW asynchronous parallel load input (PL)\. The counter is incremented on the low-to-high transition of the Clock-Up input (and a high level on the Clock-Down input) and decremented on the low to high transition of the Clock-Down input (and a high level on the Clock-up input). A high level on the MR input overrides any other input to clear the counter to its zero state. The Terminal Count up (carry) goes low half a clock period before the zero count is reached and returns to a high level at the zero count. The Terminal Count Down (borrow) in the count down mode likewise goes low half a clock period before the maximum count (9 in the 192 and 15 in the 193) and returns to high at the maximum count. Cascading is effected by connecting the carry and borrow outputs of a less significant counter to the Clock-Up and CLock-Down inputs, respectively, of the next most significant counter. If a decade counter is present to an illegal state or assumes an illegal state when power is applied, it will return to the normal sequence in one count as shown in state diagram. The ’HC192, ’HC193 and ’HCT193 are asynchronously presettable BCD Decade and Binary Up/Down synchronous counters, respectively. Presetting the counter to the number on the preset data inputs (P0-P3) is accomplished by a LOW asynchronous parallel load input (PL)\. The counter is incremented on the low-to-high transition of the Clock-Up input (and a high level on the Clock-Down input) and decremented on the low to high transition of the Clock-Down input (and a high level on the Clock-up input). A high level on the MR input overrides any other input to clear the counter to its zero state. The Terminal Count up (carry) goes low half a clock period before the zero count is reached and returns to a high level at the zero count. The Terminal Count Down (borrow) in the count down mode likewise goes low half a clock period before the maximum count (9 in the 192 and 15 in the 193) and returns to high at the maximum count. Cascading is effected by connecting the carry and borrow outputs of a less significant counter to the Clock-Up and CLock-Down inputs, respectively, of the next most significant counter. If a decade counter is present to an illegal state or assumes an illegal state when power is applied, it will return to the normal sequence in one count as shown in state diagram.

The ’HC194 and CD74HCT194 are 4-bit shift registers with Asynchronous Master Reset (MR)\. In the parallel mode (S0 and S1 are high), data is loaded into the associated flip-flop and appears at the output after the positive transition of the clock input (CP). During parallel loading serial data flow is inhibited. Shift left and shift right are accomplished synchronously on the positive clock edge with serial data entered at the shift left (DSL) serial input for the shift right mode, and at the shift right (DSR) serial input for the shift left mode. Clearing the register is accomplished by a Low applied to the Master Reset (MR)\ pin. The ’HC194 and CD74HCT194 are 4-bit shift registers with Asynchronous Master Reset (MR)\. In the parallel mode (S0 and S1 are high), data is loaded into the associated flip-flop and appears at the output after the positive transition of the clock input (CP). During parallel loading serial data flow is inhibited. Shift left and shift right are accomplished synchronously on the positive clock edge with serial data entered at the shift left (DSL) serial input for the shift right mode, and at the shift right (DSR) serial input for the shift left mode. Clearing the register is accomplished by a Low applied to the Master Reset (MR)\ pin.

The ’HC221 and CD74HCT221 are dual monostable multivibrators with reset. An external resistor (RX) and an external capacitor (CX) control the timing and the accuracy for the circuit. Adjustment of RXand CXprovides a wide range of output pulse widths from the Q and Q\ terminals. Pulse triggering on the B input occurs at a particular voltage level and is not related to the rise and fall time of the trigger pulse. Once triggered, the outputs are independent of further trigger inputs on A\ and B. The output pulse can be terminated by a LOW level on the Reset (R)\ pin. Trailing Edge triggering (A)\ and leading-edge-triggering (B) inputs are provided for triggering from either edge of the input pulse. On power up, the IC is reset. If either Mono is not used each input (on the unused device) must be terminated either high or low. The minimum value of external resistance, RX, is typically 500. The minimum value of external capacitance, CX, is 0pF. The calculation for the pulse width is tW= 0.7 RXCXat VCC= 4.5V. The ’HC221 and CD74HCT221 are dual monostable multivibrators with reset. An external resistor (RX) and an external capacitor (CX) control the timing and the accuracy for the circuit. Adjustment of RXand CXprovides a wide range of output pulse widths from the Q and Q\ terminals. Pulse triggering on the B input occurs at a particular voltage level and is not related to the rise and fall time of the trigger pulse. Once triggered, the outputs are independent of further trigger inputs on A\ and B. The output pulse can be terminated by a LOW level on the Reset (R)\ pin. Trailing Edge triggering (A)\ and leading-edge-triggering (B) inputs are provided for triggering from either edge of the input pulse. On power up, the IC is reset. If either Mono is not used each input (on the unused device) must be terminated either high or low. The minimum value of external resistance, RX, is typically 500. The minimum value of external capacitance, CX, is 0pF. The calculation for the pulse width is tW= 0.7 RXCXat VCC= 4.5V.

High Speed CMOS Logic Quad-Bus Transeciver with 3-State Outputs