Texas Instruments SN74HC148DWRG4

Overview

SN74HC148DWRG4 from Texas Instruments is an 8-line to 3-line priority encoder IC operating at 2V–6V supply, encoding eight active-low inputs into a 3-bit binary (4-2-1) output with cascading enable (EI/EO) and group-select (GS) signals. It delivers ±4-mA drive at 5V, 16ns typical propagation delay, and supports N-bit encoding in industrial control panels and keyboard scan circuits.

For engineers reviewing the SN74HC148DWRG4 datasheet, SN74HC148DWRG4 pinout, SN74HC148DWRG4 application, or SN74HC148DWRG4 equivalent, key selection criteria include low-power operation (80-μA max ICC), active-low input/output logic polarity, SOIC-16 package compatibility, and cascading capability for multi-stage priority encoding without external logic.

Technical Context

The SN74HC148DWRG4 implements combinational priority encoding where only the highest-order asserted (low) input determines the output code. Its functional modes are fully defined by EI (enable input), EO (enable output), and GS (group select) signals - all active-low - enabling seamless daisy-chaining of multiple encoders.

Inputs and outputs operate with standard CMOS voltage thresholds: VIH = 3.15V min at VCC = 4.5V, VIL = 1.35V max at same condition; output drive meets ±4 mA at 5V while maintaining VOL ≤ 0.33V and VOH ≥ 3.7V under load.

Key Specifications

Pinout & Package

SN74HC148DWRG4 is housed in a 16-pin SOIC (D) package measuring 9.90 mm × 3.90 mm with 1.27-mm pitch, RoHS-compliant, and rated for –40°C to +85°C operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LS148N, SN74HC148DWRG4 offers wider voltage range and lower power but requires careful handling of active-low logic conventions; versus 74HC148PW, it trades compactness for SOIC manufacturability and thermal mass in high-reliability assemblies.

Availability

SN74HC148DWRG4 is available at Aetrix Electronics and suitable for industrial control panels, keyboard scanning interfaces, multi-stage priority arbitration systems, and legacy code conversion circuits requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for SN74HC148DWRG4 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

Texas Instruments is a global semiconductor leader delivering analog, embedded processing, and logic solutions with emphasis on reliability, scalability, and broad application support.

The SN74HC148DWRG4 belongs to TI's 74HC logic family, designed specifically for low-power, high-noise-immunity digital interfacing in industrial, automotive, and computing systems where voltage flexibility and cascading capability are essential.

FAQ

What is the maximum propagation delay of SN74HC148DWRG4 at 6V supply?

The maximum propagation delay (tpd) for SN74HC148DWRG4 is 46ns at VCC = 6V and TA = 25°C, as specified in the Switching Characteristics table. This value applies to transitions from any input (I0–I7 or EI) to A0/A1/A2 or EO outputs under CL = 50pF load conditions. The SN74HC148DWRG4 maintains consistent timing performance across its full operating temperature range.

Does SN74HC148DWRG4 support cascading with other priority encoders?

Yes, SN74HC148DWRG4 supports hardware cascading via dedicated EI (Enable Input) and EO (Enable Output) pins. When EI is low and all inputs I0–I7 are high, EO goes low to enable the next-stage encoder. This eliminates external logic gates and enables reliable 16-input or larger priority trees using identical SN74HC148DWRG4 units.

What is the logic polarity of inputs and outputs on SN74HC148DWRG4?

All inputs (I0–I7, EI) and outputs (A0–A2, GS, EO) of SN74HC148DWRG4 are active-low. Inputs encode when pulled to GND; outputs assert low to indicate valid data or status. This polarity aligns with common switch-matrix grounding schemes and simplifies interface design with pull-up resistors and open-drain controllers.

Can SN74HC148DWRG4 operate from a 3.3V supply?

Yes, SN74HC148DWRG4 operates reliably from 3.3V supply, meeting all recommended operating conditions: VIH ≥ 2.31V and VIL ≤ 0.99V at VCC = 3.3V per TI's specification tables. Its wide 2V–6V range makes it compatible with both 3.3V and 5V systems without level shifters or voltage translators.

What package type is used for SN74HC148DWRG4?

SN74HC148DWRG4 uses a 16-pin SOIC (D) package with dimensions 9.90 mm × 3.90 mm, 1.27-mm lead pitch, and RoHS-compliant NiPdAu lead finish. It is supplied in tape-and-reel format (2500 units per reel) with MSL Level-1 rating and peak reflow tolerance up to 260°C.