Texas Instruments

This device contains four independent buffers with 3-state outputs. Each gate performs the Boolean function Y = A in positive logic. This device contains four independent buffers with 3-state outputs. Each gate performs the Boolean function Y = A in positive logic.

This device contains four independent 2-input NAND gates. Each gate performs the Boolean function Y =A ● Bin positive logic. This device contains four independent 2-input NAND gates. Each gate performs the Boolean function Y =A ● Bin positive logic.

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 ’HC153 and ’HCT153 are dual 4- to 1-line selector/multiplexers that select one of four sources for each section by the common select inputs, S0 and S1. When the enable inputs (1E\, 2E\) are HIGH, the outputs are in the LOW state. The ’HC153 and ’HCT153 are dual 4- to 1-line selector/multiplexers that select one of four sources for each section by the common select inputs, S0 and S1. When the enable inputs (1E\, 2E\) are HIGH, the outputs are in the LOW state.

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.

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 ’HC161, ’HCT161, ’HC163, and ’HCT163 are presettable synchronous counters that feature look-ahead carry logic for use in high-speed counting applications. The ’HC161 and ’HCT161 are asynchronous reset decade and binary counters, respectively; the ’HC163 and ’HCT163 devices are decade and binary counters, respectively, that are reset synchronously with the clock. Counting and parallel presetting are both accomplished synchronously with the negative-to-positive transition of the clock. A low level on the synchronous parallel enable input, SPE, disables counting operation and allows data at the P0 to P3 inputs to be loaded into the counter (provided that the setup and hold requirements for SPE are met). All counters are reset with a low level on the Master Reset input, MR. In the ’HC163 and ’HCT163 counters (synchronous reset types), the requirements for setup and hold time with respect to the clock must be met. Two count enables, PE and TE, in each counter are provided for n-bit cascading. In all counters reset action occurs regardless of the level of the SPE\, PE and TE inputs (and the clock input, CP, in the ’HC161 and ’HCT161 types). If a decade counter is preset 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 look-ahead carry feature simplifies serial cascading of the counters. Both count enable inputs (PE and TE) must be high to count. The TE input is gated with the Q outputs of all four stages so that at the maximum count the terminal count (TC) output goes high for one clock period. This TC pulse is used to enable the next cascaded stage. The ’HC161, ’HCT161, ’HC163, and ’HCT163 are presettable synchronous counters that feature look-ahead carry logic for use in high-speed counting applications. The ’HC161 and ’HCT161 are asynchronous reset decade and binary counters, respectively; the ’HC163 and ’HCT163 devices are decade and binary counters, respectively, that are reset synchronously with the clock. Counting and parallel presetting are both accomplished synchronously with the negative-to-positive transition of the clock. A low level on the synchronous parallel enable input, SPE, disables counting operation and allows data at the P0 to P3 inputs to be loaded into the counter (provided that the setup and hold requirements for SPE are met). All counters are reset with a low level on the Master Reset input, MR. In the ’HC163 and ’HCT163 counters (synchronous reset types), the requirements for setup and hold time with respect to the clock must be met. Two count enables, PE and TE, in each counter are provided for n-bit cascading. In all counters reset action occurs regardless of the level of the SPE\, PE and TE inputs (and the clock input, CP, in the ’HC161 and ’HCT161 types). If a decade counter is preset 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 look-ahead carry feature simplifies serial cascading of the counters. Both count enable inputs (PE and TE) must be high to count. The TE input is gated with the Q outputs of all four stages so that at the maximum count the terminal count (TC) output goes high for one clock period. This TC pulse is used to enable the next cascaded stage.

The ’HC161, ’HCT161, ’HC163, and ’HCT163 are presettable synchronous counters that feature look-ahead carry logic for use in high-speed counting applications. The ’HC161 and ’HCT161 are asynchronous reset decade and binary counters, respectively; the ’HC163 and ’HCT163 devices are decade and binary counters, respectively, that are reset synchronously with the clock. Counting and parallel presetting are both accomplished synchronously with the negative-to-positive transition of the clock. A low level on the synchronous parallel enable input, SPE, disables counting operation and allows data at the P0 to P3 inputs to be loaded into the counter (provided that the setup and hold requirements for SPE are met). All counters are reset with a low level on the Master Reset input, MR. In the ’HC163 and ’HCT163 counters (synchronous reset types), the requirements for setup and hold time with respect to the clock must be met. Two count enables, PE and TE, in each counter are provided for n-bit cascading. In all counters reset action occurs regardless of the level of the SPE\, PE and TE inputs (and the clock input, CP, in the ’HC161 and ’HCT161 types). If a decade counter is preset 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 look-ahead carry feature simplifies serial cascading of the counters. Both count enable inputs (PE and TE) must be high to count. The TE input is gated with the Q outputs of all four stages so that at the maximum count the terminal count (TC) output goes high for one clock period. This TC pulse is used to enable the next cascaded stage. The ’HC161, ’HCT161, ’HC163, and ’HCT163 are presettable synchronous counters that feature look-ahead carry logic for use in high-speed counting applications. The ’HC161 and ’HCT161 are asynchronous reset decade and binary counters, respectively; the ’HC163 and ’HCT163 devices are decade and binary counters, respectively, that are reset synchronously with the clock. Counting and parallel presetting are both accomplished synchronously with the negative-to-positive transition of the clock. A low level on the synchronous parallel enable input, SPE, disables counting operation and allows data at the P0 to P3 inputs to be loaded into the counter (provided that the setup and hold requirements for SPE are met). All counters are reset with a low level on the Master Reset input, MR. In the ’HC163 and ’HCT163 counters (synchronous reset types), the requirements for setup and hold time with respect to the clock must be met. Two count enables, PE and TE, in each counter are provided for n-bit cascading. In all counters reset action occurs regardless of the level of the SPE\, PE and TE inputs (and the clock input, CP, in the ’HC161 and ’HCT161 types). If a decade counter is preset 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 look-ahead carry feature simplifies serial cascading of the counters. Both count enable inputs (PE and TE) must be high to count. The TE input is gated with the Q outputs of all four stages so that at the maximum count the terminal count (TC) output goes high for one clock period. This TC pulse is used to enable the next cascaded stage.

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.

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