DM74LSAN Synchronous 4-Bit Binary Counter With Asynchronous Clear. These synchronous, presettable counters feature an internal carry look-ahead for . DM74LSAN datasheet, DM74LSAN circuit, DM74LSAN data sheet: NSC – Synchronous 4-Bit Binary Counters,alldatasheet, datasheet, Datasheet. DM74LSAN datasheet, DM74LSAN circuit, DM74LSAN data sheet: FAIRCHILD – Synchronous 4-Bit Binary Counters,alldatasheet, datasheet.
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The device should not be operated at these limits. This synchronous clear allows the count length to be modified easily, as decoding the maximum count desired can be accomplished with one external NAND gate. Internal look-ahead for fast counting. Typical propagation time, datasheeet to Q output 14 ns.
These counters feature a fully independent clock circuit. Typical power dissipation 93 mW. Carry output for n-bit cascading. The “Recommended Operating Conditions” table will define the conditions for actual device operation.
Operating Free Air Temperature Range. These counters are fully programmable; that is, the outputs may dm74,s161an preset to either level. The carry output is decoded by means of a NOR gate, thus preventing spikes during the normal counting mode of operation. The “Absolute Maximum Ratings” are those values beyond which the safety of the device cannot be guaranteed.
DM74LSAN Datasheet(PDF) – National Semiconductor (TI)
These synchronous, presettable counters feature an inter- nal carry look-ahead for application in high-speed counting designs. The carry look-ahead datsheet provides for cascading counters for n-bit synchronous applications without addi- tional gating. Instrumental in accomplishing this function are two count-enable inputs and a ripple carry output. Search field Part name Part description. Typical clock frequency 32 MHz. Free Air Operating Temperature. Devices also available in Tape and Reel.
Specify by appending the suffix letter “X” to the ordering code. Synchronous operation is pro- vided by having all flip-flops clocked simultaneously so that the outputs change coincident with each other when so instructed by the count-enable inputs and internal gating. The ripple carry output thus enabled will produce a high- level output pulse with a duration approximately equal to the high-level portion of the Q.
A buffered clock input triggers the four flip-flops on the rising positive-going edge of the clock input waveform. Clear Release Time Note 2. Clock Frequency Note 3.
The input pulses are supplied by generators having the following characteristics: Vary PRR to measure f. The clear function for the DM74LSA is synchronous; and a low level at the clear inputs sets all four of the flip-flop outputs LOW after the next clock pulse, regardless of the levels of the enable inputs. The function of the counter whether enabled, dis- abled, loading, or counting will be dictated solely dafasheet the conditions meeting the stable set-up and hold times.
As presetting is synchronous, setting up a low level at the load input disables the counter and causes the outputs to agree with the setup data after the next clock pulse, regardless of the levels of the enable input.
This mode of operation eliminates the output counting spikes which are normally associated with asynchronous ripple clock counters. Changes made to control inputs enable P or T or load that will modify the operating mode have no effect until clocking occurs. The gate output is dagasheet to the clear input to synchronously clear the counter to all low outputs. The clear function for the DM74LSA is asynchro- nous; and a low level at the clear input sets all four of the flip-flop outputs LOW, regardless of the levels of clock, load, or enable inputs.
Clock Frequency Note 2.
Fairchild Semiconductor – datasheet pdf
The parametric values defined in the Electrical Characteristics tables are not guaranteed at the absolute maximum ratings. Enable P and enable T setup times are measured at t. Clear Release Time Note 3.