Renesas 74HC148P-E

Overview

74HC148P-E from Renesas Electronics is an 8-to-3-line octal priority encoder IC with active-low inputs and outputs, designed for digital logic systems requiring encoded interrupt or request signal handling. It operates across 2–6 V supply, delivers 15 ns typical propagation delay (CL = 50 pF), supports fanout of 10 LSTTL loads, and features cascading enable input (EI) and enable output (EO) for multi-stage priority encoding in industrial control panels.

For engineers reviewing the 74HC148P-E datasheet, 74HC148P-E pinout, 74HC148P-E application, or 74HC148P-E equivalent, this device is selected for low-voltage priority encoding where input contention resolution, compact binary output (A2–A0), and guaranteed GS/EO status signaling are required - not for analog signal conditioning, clock generation, or high-speed serial interface roles.

Technical Context

The 74HC148P-E implements a fixed-function priority encoding logic with strict input priority order (input 7 highest, input 0 lowest), where only the highest-priority active-low input determines the 3-bit binary output (A2–A0). Its GS (Group Select) and EO (Enable Output) signals support daisy-chained expansion without external gates.

All inputs and outputs are TTL-compatible and actively driven low; no internal pull-ups or level-shifting circuitry is present. The device uses standard CMOS silicon process, ensuring low static current (≤4 µA at 25°C) and rail-to-rail output swing under defined load conditions.

Key Specifications

Pinout & Package

74HC148P-E is housed in a 16-pin plastic DIP (Dual In-line Package), designated PRDP0016AE-B / DP-16FV, with 2.54 mm pin pitch and through-hole mounting. Package dimensions: 19.2 mm × 6.3 mm × 3.3 mm (L × W × H), mass ≈ 1.05 g.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar priority encoding applications.

Compared with SN74HC148N and MC74HC148N, the 74HC148P-E offers the fastest propagation delay (15 ns typ) and lowest quiescent current (4 µA max), making it optimal for time-critical or battery-sensitive priority encoding tasks where marginal performance gains directly improve system responsiveness or energy efficiency.

Availability

74HC148P-E is available at Aetrix Electronics and suitable for industrial control panels, embedded keyboard interfaces, and alarm consolidation systems requiring stable component supply, long-lifecycle support, and RoHS-compliant through-hole packaging.

Supply support for 74HC148P-E includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Renesas Electronics Corporation is a Japanese semiconductor manufacturer specializing in microcontrollers, analog, and logic solutions for industrial, automotive, and infrastructure markets.

The HD74HC logic family, including the 74HC148P-E, was designed for robust, low-power digital interfacing in industrial equipment where reliability, wide voltage operation, and predictable timing are essential.

FAQ

What is the logic polarity of inputs and outputs on the 74HC148P-E?

The 74HC148P-E uses active-low logic throughout: all eight data inputs (0–7), enable input (EI), and three binary outputs (A2–A0) are asserted low. GS and EO are also active-low status indicators. This matches legacy TTL interrupt architectures and simplifies connection to open-collector or push-pull drivers operating at shared ground references.

Can the 74HC148P-E be used in a 3.3 V system?

Yes - the 74HC148P-E operates over 2.0–6.0 V, so it functions reliably at 3.3 V. Input thresholds scale with VCC, and its outputs swing rail-to-rail, ensuring clean interfacing with 3.3 V microcontrollers and FPGAs without level translation. Verified performance data (VIH/VIL, VOH/VOL) is specified across the full voltage range in the official Renesas datasheet.

How does cascading work with multiple 74HC148P-E devices?

Cascading uses EI and EO pins: the EO of a lower-priority stage connects to the EI of the next higher-priority stage. When all inputs in a stage are inactive (high), EO goes low, enabling the upstream stage. This creates a hierarchical chain where only the highest-priority asserted input across all stages produces valid A2–A0 output and pulls GS low - no external logic is needed.

Is the 74HC148P-E pin-compatible with older 74LS148 devices?

No - although functionally similar, the 74HC148P-E is not pin-compatible with the bipolar 74LS148. Pin assignments differ: LS148 places VCC at pin 16 and GND at pin 8, whereas 74HC148P-E places VCC at pin 11 and GND at pin 10. PCB layout and power routing must be redesigned to accommodate the CMOS pinout.

What is the maximum capacitive load the 74HC148P-E can drive reliably?

The 74HC148P-E is characterized for CL = 50 pF in timing specifications, and its output drive strength (fanout of 10 LSTTL loads) implies reliable operation up to ~500 pF total load capacitance when combined with appropriate series termination. For loads exceeding 50 pF, propagation delay increases predictably per datasheet curves - design validation with actual trace capacitance is recommended.