Texas Instruments SNJ54LS191W
- Part Number:
- SNJ54LS191W
- Manufacturer:
- Texas Instruments
- Ventron No:
- 6406067-SNJ54LS191W
- Description:
- Synchronous Up/Down Counters With Down/Up Mode Control
- Datasheet:
- sn54ls191
- FunctionCounter
- Bits (#)4
- Technology familyLS
- Supply voltage (min) (V)4.75
- Supply voltage (max) (V)5.25
- Input typeBipolar
- Output typePush-Pull
- FeaturesHigh speed (tpd 10-50ns)
- Operating temperature range (°C)-55 to 125
- RatingMilitary
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.
Latest News
-
13 November 2023
Do You Know About the NE555P Timer?
Ⅰ. NE555P descriptionⅡ. What are the features of NE555P timer?Ⅲ. Symbol, footprint and pin configuration of NE555P timerⅣ. What are the applications of NE555P timer?Ⅴ. Technical parameters of... -
13 November 2023
STM32F103RCT6 Microcontroller: Equivalents, Pin Configuration, Advantages and Disadvantages and More
Ⅰ. What is a microcontroller?Ⅱ. STM32F103RCT6 descriptionⅢ. Symbol, footprint and pin configuration of STM32F103RCT6 microcontrollerⅣ. Features of STM32F103RCT6 microcontrollerⅤ. Technical parameters of STM32F103RCT6 microcontrollerⅥ. Advantages and disadvantages of... -
14 November 2023
BAT54S Schottky Diode Structure, Technical Parameters, Package and Other Details
Ⅰ. Overview of BAT54S diodeⅡ. BAT54S symbol, footprint and pin configurationⅢ. Structure and working principle of BAT54S diodeⅣ. What are the features of BAT54S diode?Ⅴ. Technical parameters of... -
14 November 2023
HX711 Load Cell Amplifier: Symbol, Manufacturer, Working Principle and Applications
Ⅰ. Overview of HX711Ⅱ. HX711 symbol, footprint and pin configurationⅢ. Manufacturer of HX711Ⅳ. Features of HX711Ⅴ. Technical parameters of HX711Ⅵ. Working principle of HX711 pressure sensorⅦ. Internal block...
Help you to save your cost and time.
Reliable package for your goods.
Fast Reliable Delivery to save time.
Quality premium after-sale service.