SN74AS161
- Internal Look-Ahead Circuitry for Fast Counting
- Carry Output for n-Bit Cascading
- Synchronous Counting
- Synchronously Programmable
- Package Options Include Plastic Small-Outline (D) and Shrink Small-Outline (DB) Packages, Ceramic Chip Carriers (FK), Standard Plastic (N) and Ceramic (J) DIPs
These synchronous, presettable, 4-bit decade and binary counters feature an internal carry look-ahead circuitry for application in high-speed counting designs. The SN54ALS162B is a 4-bit decade counter. The \x92ALS161B, \x92ALS163B, \x92AS161, and \x92AS163 devices are 4-bit binary counters. Synchronous operation is provided by having all flip-flops clocked simultaneously so that the outputs change coincidentally 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 asynchronous (ripple-clock) counters. A buffered clock (CLK) input triggers the four flip-flops on the rising (positive-going) edge of the clock input waveform.
These counters are fully programmable; they can be preset to any number between 0 and 9 or 15. Because presetting is synchronous, setting up a low level at the load (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 for the \x92ALS161B and \x92AS161 devices is asynchronous. A low level at the clear (CLR\) input sets all four of the flip-flop outputs low, regardless of the levels of the CLK, LOAD\, or enable inputs. The clear function for the SN54ALS162B, \x92ALS163B, and \x92AS163 devices is synchronous, and a low level at CLR 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 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 and ENT inputs and a ripple-carry (RCO) output are instrumental in accomplishing this function. Both ENP and ENT must be high to count, and ENT is fed forward to enable RCO. RCO, thus enabled, produces a high-level pulse while the count is maximum (9 or 15, with QA high). The 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 counters 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.
The SN54ALS161B, SN54ALS162B, SN54ALS163B, SN54AS161, and SN54AS163 are characterized for operation over the full military temperature range of \x9655°C to 125°C. The SN74ALS161B, SN74ALS163B, SN74AS161, and SN74AS163 are characterized for operation from 0°C to 70°C.
관심 가지실만한 유사 제품
비교 대상 장치와 동일한 기능을 지원하는 핀 대 핀
비교 대상 장치와 유사한 기능
기술 자료
유형 | 직함 | 날짜 | ||
---|---|---|---|---|
* | Data sheet | Synchronous 4-Bit Decade And Binary Counters datasheet (Rev. A) | 2000/07/28 | |
Selection guide | Logic Guide (Rev. AB) | 2017/06/12 | ||
Application note | Understanding and Interpreting Standard-Logic Data Sheets (Rev. C) | 2015/12/02 | ||
User guide | LOGIC Pocket Data Book (Rev. B) | 2007/01/16 | ||
Application note | Semiconductor Packing Material Electrostatic Discharge (ESD) Protection | 2004/07/08 | ||
Application note | TI IBIS File Creation, Validation, and Distribution Processes | 2002/08/29 | ||
Application note | Designing With Logic (Rev. C) | 1997/06/01 | ||
Application note | Advanced Schottky Load Management | 1997/02/01 | ||
Application note | Input and Output Characteristics of Digital Integrated Circuits | 1996/10/01 | ||
Application note | Live Insertion | 1996/10/01 | ||
Application note | Advanced Schottky (ALS and AS) Logic Families | 1995/08/01 |
설계 및 개발
추가 조건 또는 필수 리소스는 사용 가능한 경우 아래 제목을 클릭하여 세부 정보 페이지를 확인하세요.
14-24-LOGIC-EVM — 14핀~24핀 D, DB, DGV, DW, DYY, NS 및 PW 패키지용 로직 제품 일반 평가 모듈
14-24-LOGIC-EVM 평가 모듈(EVM)은 14핀~24핀 D, DW, DB, NS, PW, DYY 또는 DGV 패키지에 있는 모든 로직 장치를 지원하도록 설계되었습니다.
패키지 | 핀 | CAD 기호, 풋프린트 및 3D 모델 |
---|---|---|
PDIP (N) | 16 | Ultra Librarian |
SOP (NS) | 16 | Ultra Librarian |
주문 및 품질
- RoHS
- REACH
- 디바이스 마킹
- 납 마감/볼 재질
- MSL 등급/피크 리플로우
- MTBF/FIT 예측
- 물질 성분
- 인증 요약
- 지속적인 신뢰성 모니터링
- 팹 위치
- 조립 위치