SN54ALS191A_TI 同步 4 位加/减二进制计数器

SN54ALS191A的基本参数

制造厂商：TI
产品类别：逻辑和电压转换
技术类目：触发器、锁存器和寄存器 - 计数器
功能描述：同步 4 位加/减二进制计数器
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SN54ALS191A的产品详情：

The 'ALS191A are synchronous 4-bit reversible up/down binary counters. Synchronous counting operation is provided by having all flip-flops clocked simultaneously so that the outputs change coincidentally with each other when instructed by the steering logic. This mode of operation eliminates the output counting spikes normally associated with asynchronous (ripple-clock) counters.

The outputs of the four flip-flops are triggered on a low-to-high-level transition of the clock (CLK) input if the count enable () input is low. A high at inhibits counting. The direction of the count is determined by the level of the down/up (D/U\) input. When D/U\ is low, the counter counts up, and when D/U\ is high, the counter counts down.

These counters feature a fully independent clock circuit. Changes at the control inputs ( and D/U\) that modify the operating mode have no effect on the contents of the counter until clocking occurs. The function of the counter is dictated solely by the conditions meeting the stable setup and hold times.

These counters are fully programmable. Each output can be preset to either level by placing a low on the input and entering the desired data at the data inputs. The output changes to agree with the data inputs independently of the level of the clock input. This feature allows the counters to be used as modulo-N dividers by simply modifying the count length with the preset inputs.

CLK, D/U\, and are buffered to lower the drive requirement, which significantly reduces the loading on (current required by) clock drivers, for long parallel words.

Two outputs are available to perform the cascading function: ripple clock and maximum/minimum count. The latter output produces a high-level output pulse with a duration approximately equal to one complete cycle of the clock while the count is minimum (0) counting down or maximum (15) counting up. The ripple-clock output () produces a low-level output pulse under those same conditions, but only while the clock input is low. The counter easily can be cascaded by feeding the ripple-clock output to the enable input of the succeeding counter if parallel clocking is used, or to the clock input if parallel enabling is used. The maximum/minimum count (MAX/MIN) output can be used to accomplish look ahead for high-speed operation.

The SN54ALS191A is characterized for operation over the full military temperature range of -55°C to 125°C. The SN74ALS191A is characterized for operation from 0°C to 70°C.

SN54ALS191A的优势和特性：

Single Down/Up Count-Control Line
Look-Ahead Circuitry Enhances Speed of Cascaded Counters
Fully Synchronous in Count Modes
Asynchronously Presettable With Load Control
Package Options Include Plastic Small-Outline (D) Packages, Ceramic Chip Carriers (FK), and Standard Plastic (N) and Ceramic (J) 300-mil DIPs

SN54ALS191A的参数（英文）：

Function
Counter
Bits (#)
4
Technology Family
ALS
Supply voltage (Min) (V)
4.5
Supply voltage (Max) (V)
5.5
Input type
Bipolar
Output type
Push-Pull
Features
High speed (tpd 10-50ns)

SN54ALS191A具体的完整产品型号参数及价格（美元）：

SN54ALS191A的完整型号有：5962-86840012A、5962-8684001EA、5962-8684001FA、SNJ54ALS191AFK、SNJ54ALS191AJ、SNJ54ALS191AW，以下是这些产品的关键参数及官网采购报价：

5962-86840012A，工作温度：-55 to 125，封装：LCCC (FK)-20，包装数量MPQ：1个，MSL 等级/回流焊峰值温度：N/A for Pkg Type，引脚镀层/焊球材料：SNPB，TI官网5962-86840012A的批量USD价格：22.825（1000+）

5962-8684001EA，工作温度：-55 to 125，封装：CDIP (J)-16，包装数量MPQ：1个，MSL 等级/回流焊峰值温度：N/A for Pkg Type，引脚镀层/焊球材料：SNPB，TI官网5962-8684001EA的批量USD价格：10.314（1000+）

5962-8684001FA，工作温度：-55 to 125，封装：CFP (W)-16，包装数量MPQ：1个，MSL 等级/回流焊峰值温度：N/A for Pkg Type，引脚镀层/焊球材料：SNPB，TI官网5962-8684001FA的批量USD价格：18.537（1000+）

SNJ54ALS191AFK，工作温度：-55 to 125，封装：LCCC (FK)-20，包装数量MPQ：1个，MSL 等级/回流焊峰值温度：N/A for Pkg Type，引脚镀层/焊球材料：SNPB，TI官网SNJ54ALS191AFK的批量USD价格：22.825（1000+）

SNJ54ALS191AJ，工作温度：-55 to 125，封装：CDIP (J)-16，包装数量MPQ：1个，MSL 等级/回流焊峰值温度：N/A for Pkg Type，引脚镀层/焊球材料：SNPB，TI官网SNJ54ALS191AJ的批量USD价格：10.314（1000+）

SNJ54ALS191AW，工作温度：-55 to 125，封装：CFP (W)-16，包装数量MPQ：1个，MSL 等级/回流焊峰值温度：N/A for Pkg Type，引脚镀层/焊球材料：SNPB，TI官网SNJ54ALS191AW的批量USD价格：18.537（1000+）

SN54ALS191A的评估套件：

SN54ALS191A的电路图解：

SN54ALS191A的评估套件：