Texas Instruments CD74HC238M96G4

Overview

CD74HC238M96G4 from Texas Instruments is a high-speed CMOS 3-to-8 line decoder/demultiplexer with noninverting (active-high) outputs, 2 V to 6 V supply operation, typical propagation delay of 13 ns at V_CC = 4.5 V and C_L = 15 pF, -55°C to +125°C operating temperature range, and SOIC-16 package. It serves as an address decoder in memory systems or data routing selector in industrial control logic.

For engineers reviewing the CD74HC238M96G4 datasheet, CD74HC238M96G4 pinout, CD74HC238M96G4 application, or CD74HC238M96G4 equivalent, key selection criteria include active-high output behavior, triple enable inputs (G2, G1, G0) for cascading, LSTTL-compatible fanout (10 loads), wide voltage tolerance, and military-grade temperature support.

Technical Context

The CD74HC238M96G4 implements a 3-input address decoding function where A2–A0 select one of eight outputs (Y0–Y7), all driven high when enabled and unselected. Its three strobe inputs-G2 (active-high), G1 and G0 (active-low)-allow hierarchical enable control across multiple decoders without external logic.

Unlike the '138 variant, the '238 family forces all outputs low when any strobe is asserted and drives only the selected output high otherwise. This active-high decode behavior enables direct interface with LED drivers, relay drivers, or high-side switch controllers requiring asserted-high enable signals.

Key Specifications

Pinout & Package

CD74HC238M96G4 is housed in a 16-pin SOIC (D) package measuring 9.90 mm × 3.90 mm, RoHS-compliant with NiPdAu lead finish and MSL Level-1 rating.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CD74HC138M96G4 and SN74HC238N, the CD74HC238M96G4 uniquely combines active-high outputs, SOIC-16 compactness, and full military temperature range - making it optimal for space-constrained, high-reliability systems requiring direct high-side switching.

Availability

CD74HC238M96G4 is available at Aetrix Electronics and suitable for memory address decoding, industrial I/O expansion, test equipment multiplexing, and automotive body control modules requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for CD74HC238M96G4 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 company headquartered in Dallas, Texas, delivering analog and embedded processing solutions for industrial, automotive, personal electronics, and communications markets.

The CD74HC238M96G4 belongs to TI's High-Speed CMOS Logic (HC) family, engineered for low-power, wide-voltage, and extended-temperature operation in mission-critical digital control and interface applications.

FAQ

What is the output behavior of CD74HC238M96G4 when an enable input is asserted?

When any enable input (G0, G1, or G2) is asserted - specifically G0 or G1 low, or G2 high - all eight outputs (Y0–Y7) of the CD74HC238M96G4 are forced low. Only when G0 and G1 are high *and* G2 is low does the decoder respond to A2–A0, driving exactly one output high while holding the others low. This behavior is confirmed in Table 7-2 of the TI datasheet SCHS147J.

Does CD74HC238M96G4 support 3.3 V logic systems?

Yes, CD74HC238M96G4 fully supports 3.3 V operation: its V_CC range is 2 V to 6 V, and input thresholds scale with V_CC (VIH = 1.5 V min at 2 V, 3.15 V min at 4.5 V). At 3.3 V, VIH ≈ 2.3 V and VIL ≈ 1.0 V, ensuring robust compatibility with standard 3.3 V CMOS outputs. Output VOH exceeds 3.1 V at I_OH = –4 mA, meeting 3.3 V logic-high requirements.

Can CD74HC238M96G4 replace CD74HC138M96G4 without circuit changes?

No - CD74HC238M96G4 cannot directly replace CD74HC138M96G4 without modifying downstream logic. The CD74HC138M96G4 has active-low outputs (Y0–Y7 low when selected), whereas CD74HC238M96G4 has active-high outputs. Swapping them would invert all decoded signals, causing functional failure unless external inverters or firmware logic adjustments are added.

What is the maximum capacitive load CD74HC238M96G4 can drive while maintaining specified timing?

CD74HC238M96G4 is characterized for timing up to 50 pF load capacitance, with t_pd = 45 ns max at V_CC = 4.5 V and T_A = –55°C to 125°C. Driving >50 pF increases propagation delay nonlinearly and may cause output transition time degradation. For loads exceeding 50 pF, TI recommends adding a buffer stage or reducing trace length and using controlled-impedance routing to maintain signal integrity in the CD74HC238M96G4 application.

Is CD74HC238M96G4 pin-compatible with other packages in the same family?

Yes - CD74HC238M96G4 (SOIC-16) shares identical pin numbering and function mapping with CD74HC238E (PDIP-16), CD74HC238NSR (SOP-16), and CD74HC238PWR (TSSOP-16). All variants use the same 16-pin layout per Figure 4 of SCHS147J: A0 on pin 1, V_CC on pin 16, GND on pin 8, and Y0–Y7 distributed identically. Mechanical dimensions differ, but PCB footprint and netlist remain interchangeable across packages.