74LS20 Dual Four input NAND in Pakistan

The 74LS189 is a high-speed 64-bit RAM organized as a 16-word by the 4-bit array. Address inputs are buffered to minimize loading and are fully decoded on-chip. The outputs are 3-state and are in the high impedance state whenever the Chip Select (CS) input is HIGH. The outputs are active only in the read mode and the output data is the complement of the stored data.

74LS Series ICs are High-Speed Logic gates, ideally a little faster than the 74HC series but more power consumption is required. They are implemented with a Low-Power Schottky diode technology to achieve high switching speed. 74LS148 is one of the 74LS series IC. 74LS148 ICs contain an 8 to 3-Bit priority encoder that converts 8 Data Lines to 3-Line binary. Cascading circuitry (enable input EI and enable output EO) has been provided to allow octal expansion without the need for external circuitry.

The 74LS138 is a 3:8 Decoder IC that is commonly used in decoding or de-multiplexing circuits for memory decoding or data routing purposes. It is designed for high-speed operations and has three enable pins to make it easier to cascade with other ICs. The device decodes 1-of-8 lines, set by x3 binary select inputs & three enable inputs. The LS138 can be used as an 8- output demultiplexer by using one active LOW Enable input as data input & the other Enable inputs as strobes. The IC has an operating voltage from 1.0V to 5.5V with a low power consumption of 32mW. The propagation delay is around 21nS.