The ’ACT163 devices are 4-bit binary counters. These synchronous, presettable counters feature an internal carry look-ahead for application in high-speed counting designs. Synchronous operation is provided by having all flip-flops clocked simultaneously so that the outputs change, coincident with each other, when instructed by the count-enable (ENP, ENT) inputs and internal gating. This mode of operation eliminates the output counting spikes normally associated with synchronous (ripple-clock) counters. A buffered clock (CLK) input triggers the four flip-flops on the rising (positive-going) edge of the clock waveform.
The counters are fully programmable; that is, they can be preset to any number between 0 and 9 or 15. Presetting is synchronous; therefore, 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 inputs.
The clear function is synchronous. A low level at the clear (CLR)\ input sets all four of the flip-flop outputs low after the next low-to-high transition of CLK, regardless of the levels of the enable inputs. This synchronous clear allows the count length to be modified easily by decoding the Q outputs for the maximum count desired. The active-low output of the gate used for decoding is connected to CLR\ to synchronously clear the counter to 0000 (LLLL).
The carry look-ahead circuitry provides for cascading counters for n-bit synchronous applications without additional gating. ENP, ENT, and a ripple-carry output (RCO) are instrumental in accomplishing this function. Both ENP and ENT must be high to count, and ENT is fed forward to enable RCO. Enabling RCO produces a high-level pulse while the count is maximum (9 or 15 with QA high). This high-level overflow ripple-carry pulse can be used to enable successive cascaded stages. Transitions at ENP or ENT are allowed, regardless of the level of CLK.
These devices feature a fully independent clock circuit. Changes at control inputs (ENP, ENT, or LOAD\) that modify the operating mode have no effect on the contents of the counter until clocking occurs. The function of the counter (whether enabled, disabled, loading, or counting) is dictated solely by the conditions meeting the stable setup and hold times.
| Tipo | Título | Fecha | ||
|---|---|---|---|---|
| * | Data sheet | CD54ACT163, CD74ACT163 datasheet (Rev. B) | 24 mar 2003 | |
| Application note | Implications of Slow or Floating CMOS Inputs (Rev. E) | 26 jul 2021 | ||
| Selection guide | Logic Guide (Rev. AB) | 12 jun 2017 | ||
| Application note | Understanding and Interpreting Standard-Logic Data Sheets (Rev. C) | 02 dic 2015 | ||
| User guide | LOGIC Pocket Data Book (Rev. B) | 16 ene 2007 | ||
| Application note | Semiconductor Packing Material Electrostatic Discharge (ESD) Protection | 08 jul 2004 | ||
| Application note | Selecting the Right Level Translation Solution (Rev. A) | 22 jun 2004 | ||
| Application note | TI IBIS File Creation, Validation, and Distribution Processes | 29 ago 2002 | ||
| Application note | CMOS Power Consumption and CPD Calculation (Rev. B) | 01 jun 1997 | ||
| Application note | Designing With Logic (Rev. C) | 01 jun 1997 | ||
| Application note | Using High Speed CMOS and Advanced CMOS in Systems With Multiple Vcc | 01 abr 1996 |
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|---|---|---|
| PDIP (N) | 16 | Ver opciones |
| SOIC (D) | 16 | Ver opciones |
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