Texas Instruments

The SNx4HC112 devices contain two independent J-K negative-edge-triggered flip-flops. A low level at the preset (PRE) or clear (CLR) inputs sets or resets the outputs, regardless of the levels of the other inputs. When PRE and CLR are inactive (high), data at the J and K inputs meeting the setup time requirements are transferred to the outputs on the negative-going edge of the clock (CLK) pulse. Clock triggering occurs at a voltage level and is not directly related to the fall time of the CLK pulse. Following the hold-time interval, data at the J and K inputs may be changed without affecting the levels at the outputs. These versatile flip-flops perform as toggle flip-flops by tying J and K high. The SNx4HC112 devices contain two independent J-K negative-edge-triggered flip-flops. A low level at the preset (PRE) or clear (CLR) inputs sets or resets the outputs, regardless of the levels of the other inputs. When PRE and CLR are inactive (high), data at the J and K inputs meeting the setup time requirements are transferred to the outputs on the negative-going edge of the clock (CLK) pulse. Clock triggering occurs at a voltage level and is not directly related to the fall time of the CLK pulse. Following the hold-time interval, data at the J and K inputs may be changed without affecting the levels at the outputs. These versatile flip-flops perform as toggle flip-flops by tying J and K high.

The ’HC123, ’HCT123, CD74HC423 and CD74HCT423 are dual monostable multivibrators with resets. They are all retriggerable and differ only in that the 123 types can be triggered by a negative to positive reset pulse; whereas the 423 types do not have this feature. An external resistor (RX) and an external capacitor (CX) control the timing and the accuracy for the circuit. Adjustment of Rx and CXprovides a wide range of output pulse widths from the Q and Q\ terminals. Pulse triggering on the A\ and B inputs occur at a particular voltage level and is not related to the rise and fall times of the trigger pulses. Once triggered, the output pulse width may be extended by retriggering inputs 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. If either Mono is not used each input on the unused device (A\, B, and R\) must be terminated high or low. The minimum value of external resistance, Rx is typically 5k. The minimum value external capacitance, CX, is 0pF. The calculation for the pulse width is tW= 0.45 RXCXat VCC= 5V. The ’HC123, ’HCT123, CD74HC423 and CD74HCT423 are dual monostable multivibrators with resets. They are all retriggerable and differ only in that the 123 types can be triggered by a negative to positive reset pulse; whereas the 423 types do not have this feature. An external resistor (RX) and an external capacitor (CX) control the timing and the accuracy for the circuit. Adjustment of Rx and CXprovides a wide range of output pulse widths from the Q and Q\ terminals. Pulse triggering on the A\ and B inputs occur at a particular voltage level and is not related to the rise and fall times of the trigger pulses. Once triggered, the output pulse width may be extended by retriggering inputs 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. If either Mono is not used each input on the unused device (A\, B, and R\) must be terminated high or low. The minimum value of external resistance, Rx is typically 5k. The minimum value external capacitance, CX, is 0pF. The calculation for the pulse width is tW= 0.45 RXCXat VCC= 5V.

The CD74HC137, CD74HCT137, ’HC237, and CD74HCT237 are high speed silicon gate CMOS decoders well suited to memory address decoding or data routing applications. Both circuits feature low power consumption usually associated with CMOS circuitry, yet have speeds comparable to low power Schottky TTL logic. Both circuits have three binary select inputs (A0, A1 and A2) that can be latched by an active High Latch Enable (LE) signal to isolate the outputs from select-input changes. A "Low" LE makes the output transparent to the input and the circuit functions as a one-of-eight decoder. Two Output Enable inputs (OE\1and OE0) are provided to simplify cascading and to facilitate demultiplexing. The demultiplexing function is accomplished by using the A0, A1, A2inputs to select the desired output and using one of the other Output Enable inputs as the data input while holding the other Output Enable input in its active state. In the CD74HC137 and CD74HCT137 the selected output is a "Low"; in the ’HC237 and CD74HCT237 the selected output is a "High". The CD74HC137, CD74HCT137, ’HC237, and CD74HCT237 are high speed silicon gate CMOS decoders well suited to memory address decoding or data routing applications. Both circuits feature low power consumption usually associated with CMOS circuitry, yet have speeds comparable to low power Schottky TTL logic. Both circuits have three binary select inputs (A0, A1 and A2) that can be latched by an active High Latch Enable (LE) signal to isolate the outputs from select-input changes. A "Low" LE makes the output transparent to the input and the circuit functions as a one-of-eight decoder. Two Output Enable inputs (OE\1and OE0) are provided to simplify cascading and to facilitate demultiplexing. The demultiplexing function is accomplished by using the A0, A1, A2inputs to select the desired output and using one of the other Output Enable inputs as the data input while holding the other Output Enable input in its active state. In the CD74HC137 and CD74HCT137 the selected output is a "Low"; in the ’HC237 and CD74HCT237 the selected output is a "High".

The CDx4HC147 and CD74HCT147 are 9-input priority encoders. These devices provide the 10-line to 4-line priority encoding function by use of the implied decimal "zero." The CDx4HC147 and CD74HCT147 are 9-input priority encoders. These devices provide the 10-line to 4-line priority encoding function by use of the implied decimal "zero."

The ’HC154 and ’HCT154 are 4-to-16 line decoders/demultiplexers with two enable inputs, E1 and E2. A High on either enable input forces the output into the High state. The demultiplexing function is performed by using the four input lines, A0 to A3, to select the output lines Y0\ to Y15\, and using one enable as the data input while holding the other enable low. The ’HC154 and ’HCT154 are 4-to-16 line decoders/demultiplexers with two enable inputs, E1 and E2. A High on either enable input forces the output into the High state. The demultiplexing function is performed by using the four input lines, A0 to A3, to select the output lines Y0\ to Y15\, and using one enable as the data input while holding the other enable low.

High Speed CMOS Logic 8-Bit Parallel-In/Serial-Out Shift Register

High Speed CMOS Logic Quad D-Type Flip-Flops with 3-State Outputs

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.