STMicroelectronics M74HC148M1R 8-to-3 Line Priority Encoder

The M74HC148M1R from STMicroelectronics is a high-speed CMOS 8-to-3 line priority encoder designed to address the needs of system designers looking for a device capable of encoding eight input lines to three output lines. The inputs and outputs are fully compatible with standard CMOS, NMOS, and TTL logic levels, making this encoder a versatile choice for interfacing with various digital systems.

This encoder features eight active-low inputs and provides an active-low output, ensuring that the highest-order input line with a low level is encoded to the output lines. The priority encoding ensures that if two or more inputs are simultaneously active, the input with the highest priority is represented on the output. The priority is determined by the input line number, with input I0 having the highest priority and I7 the lowest.

The M74HC148M1R is equipped with an additional active-low enable input (EI) which, when held low, forces the encoder to function normally. If EI is held high, all outputs remain high, effectively disabling the encoding function. This feature allows for the expansion of the encoder to handle more inputs or to inhibit the encoding operation without powering down the device.

As part of the high-speed CMOS family, this encoder benefits from the low power dissipation characteristics inherent to the technology. It operates over a broad voltage range from 2V to 6V and provides standard outputs which can drive up to 10 LSTTL loads. This makes the M74HC148M1R a suitable choice for battery-operated and portable applications where power efficiency is critical.

The device is offered in a small outline package (SOP), specifically in an SO-16 package type, making it a compact solution for space-constrained applications. It is also characterized by its robustness, with ESD protection and latch-up immunity, ensuring reliable operation even in harsh electrical environments.

Whether used in microprocessor systems, computer control systems, or signal routing applications, the M74HC148M1R from STMicroelectronics stands out as a dependable and efficient solution for priority encoding needs.