SN54LS191_TI 具有加/减模式控制的同步加/减计数器

SN54LS191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：具有加/减模式控制的同步加/减计数器
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SN54LS191的产品详情：

The '190, 'LS190, '191, and 'LS191 are synchronous, reversible up/down counters having a complexity of 58 equivalent gates. The '191 and 'LS191 are 4-bit binary counters and the '190 and 'LS190 are BCD 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 steering logic. This mode of operation eliminates the output counting spikes normally associated with asynchronous (ripple clock) counters.

The outputs of the four master-slave flip-flops are triggered on a low-to-high transition of the clock input if the enable input is low. A high at the enable input inhibits counting. Level changes at the enable input should be made only when the clock input is high. The direction of the count is determined by the level of the down/up input. When low, the counter count up and when high, it counts down. A false clock may occur if the down/up input changes while the clock is low. A false ripple carry may occur if both the clock and enable are low and the down/up input is high during a load pulse.

These counters are fully programmable; that is, the outputs may be preset to either level by placing a low on the load input and entering the desired data at the data inputs. The output will change 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.

The clock, down/up, and load inputs are buffered to lower the drive requirement which significantly reduces the number of clock drivers, etc., required for long parallel words.

Two outputs have been made 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 when the counter overflows or underflows. The ripple clock output produces a low-level output pulse equal in width to the low-level portion of the clock input when an overflow or underflow condition exists. The counters can be easily 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 output can be used to accomplish look-ahead for high-speed operation.

Series 54' and 54LS' are characterized for operation over the full military temperature range of -55°C to 125°C; Series 74' and 74LS' are characterized for operation from 0°C to 70°C.

SN54LS191的优势和特性：

Counts 8-4-2-1 BCD or Binary
Single Down/Up Count Control Line
Count Enable Control Input
Ripple Clock Output for Cascading
Asynchronously Presettable with Load Control
Parallel Outputs
Cascadable for n-Bit Applications

SN54LS191的参数（英文）：

Function
Counter
Bits (#)
4
Technology Family
LS
Supply voltage (Min) (V)
4.75
Supply voltage (Max) (V)
5.25
Input type
Bipolar
Output type
Push-Pull
Features
High speed (tpd 10-50ns)

SN54LS191具体的完整产品型号参数及价格（美元）：

SN54LS191的完整型号有：7600901EA、7600901FA、JM38510/31509BEA、JM38510/31509BFA、M38510/31509BEA、M38510/31509BFA、SN54LS191J、SNJ54LS191FK、SNJ54LS191J、SNJ54LS191W，以下是这些产品的关键参数及官网采购报价：

7600901EA，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7600901EA的批量USD价格：10.497（1000+）

7600901FA，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7600901FA的批量USD价格：23.601（1000+）

JM38510/31509BEA，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JM38510/31509BEA的批量USD价格：8.729（1000+）

JM38510/31509BFA，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JM38510/31509BFA的批量USD价格：19.386（1000+）

M38510/31509BEA，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M38510/31509BEA的批量USD价格：8.729（1000+）

M38510/31509BFA，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M38510/31509BFA的批量USD价格：19.386（1000+）

SN54LS191J，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SN54LS191J的批量USD价格：7.765（1000+）

SNJ54LS191FK，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SNJ54LS191FK的批量USD价格：18.439（1000+）

SNJ54LS191J，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SNJ54LS191J的批量USD价格：10.497（1000+）

SNJ54LS191W，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SNJ54LS191W的批量USD价格：23.601（1000+）

SN54LS191的评估套件：

SN54LS191的电路图解：

SN54LS191的评估套件：