Texas Instruments CD74HC238PWRG4

Overview

CD74HC238PWRG4 from Texas Instruments is a high-speed CMOS 3-to-8 line decoder/demultiplexer with active-high outputs, 2 V to 6 V supply operation, typical 13 ns propagation delay at 5 V/15 pF, and -55°C to +125°C operating temperature range. It serves as an address decoder in memory systems or data routing selector in industrial control logic.

For engineers reviewing the CD74HC238PWRG4 datasheet, CD74HC238PWRG4 pinout, CD74HC238PWRG4 application, or CD74HC238PWRG4 equivalent, key selection criteria include its noninverting output polarity, three enable inputs for cascading, LSTTL-compatible fanout, wide voltage range, and TSSOP-16 package suitability for space-constrained PCBs.

Technical Context

The CD74HC238PWRG4 implements a silicon-gate CMOS 3:8 decoder with three address inputs (A0–A2) and three strobe inputs (G2, G1, G0), where G2 is active-high and G1/G0 are active-low. All eight outputs (Y0–Y7) are active-high - only the selected output goes high when strobes are inactive; all outputs go low when any strobe is asserted.

It operates across 2 V–6 V with CMOS-level input thresholds (VIH = 1.5 V min at 2 V, 3.15 V min at 4.5 V), supports 10 LSTTL loads on standard outputs, and delivers balanced transition times (13 ns typ tpd, 15 ns typ tt at 4.5 V/15 pF), enabling reliable timing in synchronous digital systems.

Key Specifications

Pinout & Package

TSSOP-16 package (5.00 mm × 4.40 mm body, 0.65 mm pitch), lead-free (NIPDAU), moisture sensitivity level 1 (260°C reflow compatible).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 3-to-8 decoder applications.

Compared with CD74HC138PWRG4, the CD74HC238PWRG4 eliminates external inversion for high-true enables, while SN74HC238PW offers identical functionality with simplified part numbering - both alternatives retain full pin compatibility and electrical behavior across -55°C to +125°C.

Availability

CD74HC238PWRG4 is available at Aetrix Electronics and suitable for memory address decoding, industrial I/O expansion, embedded boot selection, and peripheral multiplexing requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for CD74HC238PWRG4 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 specializing in analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.

The CD74HC238PWRG4 belongs to TI's HC-series high-speed CMOS logic family, designed for low-power, wide-voltage-range digital interfacing in harsh-environment applications where reliability and temperature resilience are critical.

FAQ

What is the output polarity of CD74HC238PWRG4 compared to CD74HC138PWRG4?

The CD74HC238PWRG4 features active-high outputs (Yx = HIGH when selected), whereas CD74HC138PWRG4 has active-low outputs (Yx = LOW when selected). This fundamental polarity difference means CD74HC238PWRG4 directly drives high-true enables without external inverters, reducing component count in systems like FPGA configuration or relay control where active-high signaling is required.

Can CD74HC238PWRG4 operate at 3.3 V supply voltage?

Yes, CD74HC238PWRG4 supports 2 V to 6 V operation, including 3.3 V nominal supply. At VCC = 3.3 V, VIH is guaranteed ≥2.1 V and VIL ≤1.0 V per datasheet specs, providing >1.2 V noise margin - making it fully compatible with 3.3 V microcontrollers and FPGAs without level translation.

What is the maximum output sink/source current for CD74HC238PWRG4?

CD74HC238PWRG4 delivers ±4 mA output drive capability at VCC = 4.5 V (per Electrical Characteristics table). This allows direct interface with LEDs (with series resistor), small-signal transistors, or other logic inputs. Exceeding ±4 mA risks violating VOL/VOH specs or degrading propagation delay, so external buffers are recommended for higher-current loads.

How does the enable logic work on CD74HC238PWRG4?

CD74HC238PWRG4 uses three enable inputs: G2 (active-high) and G0/G1 (active-low). All three must be asserted (G2 = HIGH, G0 = LOW, G1 = LOW) for normal decoding. If any enable is inactive, all outputs force LOW. This architecture enables hierarchical decoding - e.g., G2 from upper address bits, G0/G1 from system mode signals - ensuring deterministic output states during reset or fault conditions.

Is CD74HC238PWRG4 pin-compatible with CD74HCT238PWR?

Yes, CD74HC238PWRG4 and CD74HCT238PWR share identical TSSOP-16 pinout and pin functions. However, CD74HCT238PWR is TTL-compatible (4.5 V–5.5 V only, VIH = 2 V min), while CD74HC238PWRG4 operates from 2 V–6 V with CMOS thresholds. They are not functionally interchangeable across all voltage domains - verify supply and input logic levels before substitution.