SN54LS163A
'160, '161, 'LS160A, 'LS161A … SYNCHRONOUS COUNTERS WITH DIRECT CLEAR '162, '163, 'LS162A, 'LS163A, 'S162, 'S163 … FULLY SYNCHRONOUS COUNTERS
- Internal Look-Ahead for Fast Counting
- Carry Output for n-Bit Cascading
- Synchronous Counting
- Synchronously Programmable
- Load Control Line
- Diode-Clamped Inputs
These synchronous, presettable counters feature an internal carry look-ahead for application in high-speed counting designs. The '160, '162, 'LS160A, 'LS162A, and 'S162 are decade counters and the '161, '163, 'LS161A, 'LS163A, and 'S163 are 4-bit binary counters. Synchronous operation is provided 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. This mode of operation eliminates the output counting spikes that are normally associated with asynchronous (ripple clock) counters, however counting spikes may occur on the (RCO) ripple carry output. A buffered clock input triggers the four flip-flops on the rising edge of the clock input waveform.
These counters are fully programmable; that is, the outputs may be preset to either level. 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 inputs. Low-to-high transitions at the load input of the '160 thru '163 should be avoided when the clock is low if the enable inputs are high at or before the transition. This restriction is not applicable to the 'LS160A thru 'LS163A or 'S162 or 'S163. The clear function for the '160, '161, 'LS160A, and 'LS161A is asynchronous 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. The clear function for the '162, '163, 'LS162A, 'LS163A, 'S162, and 'S163 is synchronous and a low level at the clear input sets all four of the flip-flop outputs low after the next clock pulse, regardless of the levels of the enable inputs. 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. The gate output is connected to the clear input to synchronously clear the counter to 0000 (LLLL). Low-to-high transitions at the clear input of the '162 and '163 should be avoided when the clock is low if the enable and load inputs are high at or before the transition.
The carry look-ahead circuitry provides for cascading counters for n-bit synchronous applications without additional gating. Instrumental in accomplishing this function are two count-enable inputs and a ripple carry output. Both count-enable inputs (P and T) must be high to count, and input T is fed forward to enable the ripple carry output. 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 QA output. This high-level overflow ripple carry pulse can be used to enable successive cascaded stages. High-to-low level transitions at the enable P or T inputs of the '160 thru '163 should occur only when the clock input is high. Transitions at the enable P or T inputs of the 'LS160A thru 'LS163A or 'S162 and 'S163 are allowed regardless of the level of the clock input.
'LS160A thru 'LS163A, 'S162 and 'S163 feature a fully independent clock circuit. Changes at control inputs (enable P or T, or load) that will modify the operating mode have no effect until clocking occurs. The function of the counter (whether enabled, disabled, loading, or counting) will be dictated solely by the conditions meeting the stable setup and hold times.
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技術文件
類型 | 標題 | 日期 | ||
---|---|---|---|---|
* | Data sheet | Synchronous 4-Bit Counters datasheet | 1988年 3月 1日 | |
* | SMD | SN54LS163A SMD 76034012A | 2016年 6月 21日 | |
Selection guide | Logic Guide (Rev. AB) | 2017年 6月 12日 | ||
Application note | Understanding and Interpreting Standard-Logic Data Sheets (Rev. C) | 2015年 12月 2日 | ||
User guide | LOGIC Pocket Data Book (Rev. B) | 2007年 1月 16日 | ||
Application note | Semiconductor Packing Material Electrostatic Discharge (ESD) Protection | 2004年 7月 8日 | ||
Application note | TI IBIS File Creation, Validation, and Distribution Processes | 2002年 8月 29日 | ||
Application note | Designing With Logic (Rev. C) | 1997年 6月 1日 | ||
Application note | Designing with the SN54/74LS123 (Rev. A) | 1997年 3月 1日 | ||
Application note | Input and Output Characteristics of Digital Integrated Circuits | 1996年 10月 1日 | ||
Application note | Live Insertion | 1996年 10月 1日 |
設計與開發
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封裝 | 針腳 | CAD 符號、佔位空間與 3D 模型 |
---|---|---|
CDIP (J) | 16 | Ultra Librarian |
CFP (W) | 16 | Ultra Librarian |
LCCC (FK) | 20 | Ultra Librarian |
訂購與品質
- RoHS
- REACH
- 產品標記
- 鉛塗層/球物料
- MSL 等級/回焊峰值
- MTBF/FIT 估算值
- 材料內容
- 認證摘要
- 進行中持續性的可靠性監測
- 晶圓廠位置
- 組裝地點