Description of NXP 74HC191N
The NXP 74HC191N is a high-speed Si-gate CMOS device and is pin compatible with low-power Schottky TTL (LSTTL). It is fabricated with silicon gate CMOS technology which ensures low power consumption and a broad operating voltage range. This integrated circuit is a 4-bit binary up/down counter that is part of the 74HC/HCT family, known for its robustness and versatility in various digital applications.
The 74HC191N is designed to have two modes of operation: it can count up from 0 to 15 (binary) and it can count down from 15 to 0. The counting operation is controlled by two inputs: UP/DOWN and a dual clock. The UP/DOWN input determines the direction of the count, and the dual clock input consists of two separate clock signals, one for the up count and one for the down count. This allows for precise control over the counting sequence and makes the device suitable for a wide range of applications, such as programmable dividers, counters, and clocks.
Key features of the 74HC191N include an asynchronous master reset input (MR) which clears the counter to its zero state when a high level is applied, regardless of other inputs. Additionally, the counter has an output carry lookahead for n-bit cascading and a ripple clock output for cascading without the need for external circuitry. The outputs change state on the rising edge of the clock pulse, ensuring synchronous operation for the counting sequence.
The 74HC191N operates over a wide voltage range from 2.0 to 6.0 V and features standard 16-pin DIP (Dual Inline Package) making it easy to integrate into various circuit boards. The device also includes output capability of standard I/O, which allows for direct driving of TTL loads. It is specified in compliance with JEDEC standard no. 7A, ensuring reliability and consistency in performance across different environments.
Overall, the NXP 74HC191N is a versatile and reliable component suitable for implementing counters and dividers in digital electronics, offering designers a mix of speed, power efficiency, and ease of use for their digital counting applications.
