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Home > Products > Integrated Circuits (ICs) > Logic > Signal Switches, Multiplexers, Decoders

STMicroelectronics 74VHC238MTR

Name: 74VHC238MTR
Brand: STMicroelectronics
SKU: 74VHC238MTR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 74VHC238MTR

Manufacturer:: STMicroelectronics

Category:: Signal Switches, Multiplexers, Decoders

Package:: 16-SOIC (0.154", 3.90mm Width)

Datasheet:: 74VHC238MTR.pdf

Description:: IC DECODER/DEMUX 1 X 3:8 16SO

Quantity:: RFQ Add To RFQ list

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Product details

Overview

74VHC238MTR from STMicroelectronics is a high-speed CMOS 3-to-8 line decoder with pin- and function-compatibility to standard 74-series decoders. It features 5.5 ns typical propagation delay at 5 V, 2 V to 5.5 V operating voltage range, symmetrical 8 mA output drive, and power-down input protection enabling safe 5 V ↔ 3 V interfacing in memory address decoding systems.

For engineers reviewing the 74VHC238MTR datasheet, 74VHC238MTR pinout, 74VHC238MTR application, or 74VHC238MTR equivalent, key selection criteria include enable-input logic architecture (G1 low / G2A-G2B high inhibit), balanced tPLH/tPHL delays, ESD-hardened inputs (2 kV), and SO-16 package compatibility with legacy 74-series layouts.

Technical Context

The device implements active-high 3-bit binary decoding with three independent enable inputs (G1, G2A, G2B) supporting cascaded memory address decoding. Its C2MOS process ensures latch-up immunity and operation across –55°C to +125°C with no external pull-ups required.

All inputs accept 0–7 V regardless of VCC, enabling robust level translation. Outputs are non-inverting, rail-to-rail compatible, and specified for 8 mA sink/source at VCC = 5 V with VOL ≤ 0.55 V and VOH ≥ 3.7 V under load.

Key Specifications

Parameter	Value and Actual Design Meaning
tPD (typ)	5.5 ns at VCC = 5 V - enables sub-10 ns timing margins in high-speed address decode paths
VCC Range	2 V to 5.5 V - supports mixed-voltage system interfacing including 3.3 V and 5 V domains
IOL / IOH (min)	8 mA - drives standard TTL loads without external buffers in memory select circuits
VIH / VIL Thresholds	0.7VCC / 0.3VCC - provides 28% noise margin for reliable logic-level discrimination
ICC (max)	4 µA at TA = 25°C - enables ultra-low static power in battery-backed or standby systems
ESD Rating	2 kV HBM - eliminates need for external transient protection on control lines
Input Voltage Range	–0.5 V to +7.0 V - allows safe hot-plug and overvoltage-tolerant operation independent of supply

Pinout & Package

74VHC238MTR is housed in a 16-pin SOIC (Small Outline Integrated Circuit) package with 1.27 mm pitch, compliant with JEDEC MS-012. Pin 1 is marked by a beveled corner or notch; pin 8 is GND and pin 16 is VCC.

Pin/Terminal	Circuit Role	Design Meaning
1, 2, 3 (A, B, C)	Binary Address Inputs	Select one of eight outputs (Y0–Y7); decoded only when all enables satisfy truth table condition
4, 5 (G2A, G2B)	Active-High Enable Inputs	Both must be low for decode activation; used for hierarchical enable chaining in multi-chip memory systems
6 (G1)	Active-Low Enable Input	Must be high to enable; complements G2A/G2B for flexible enable polarity mixing
7–15 (Y0–Y7)	Active-High Decoder Outputs	Only one asserted per valid input combination; all low when disabled - no floating states
8 (GND)	Ground Reference	Return path for all internal logic and output drivers; requires low-inductance connection
16 (VCC)	Positive Supply	Power source for internal logic and output stages; bypassing with 100 nF ceramic near pin is mandatory

Key Features

Feature	Design Value
Power-down input protection	Accepts 0–7 V on all inputs regardless of VCC - enables safe hot-swap and voltage-domain isolation
Symmetrical output drive	\|IOH\| = IOL = 8 mA min - eliminates need for external pull-ups/pull-downs in bus-driven applications
Balanced propagation delays	tPLH ≅ tPHL - prevents pulse distortion in time-critical enable/decode sequences
High noise immunity	VNIH = VNIL = 28% VCC min - rejects >700 mV of coupled noise on 5 V rails
Latch-up immunity	Enhanced C2MOS process - meets JEDEC JESD78 Class II (>100 mA) without external current limiting

Applications

Memory Address Decoding

Peripheral Select Logic

Use Scenario: Selecting one of eight RAM/ROM chips in a microcontroller-based embedded system with 16-bit address bus.

IC Role / Device Role / Timing Role: 3-bit address decoder generating chip-select signals synchronized to address setup/hold windows.

Use Value: 5.5 ns tPD ensures <10 ns decode latency, meeting tight timing budgets for 20+ MHz bus cycles.

Use Scenario: Enabling discrete peripherals (ADC, DAC, UART) via GPIO-controlled address lines on an FPGA carrier board.

IC Role / Device Role / Timing Role: Level-translating decoder translating 3.3 V FPGA outputs to 5 V peripheral enables while tolerating supply variance.

Use Value: Input overvoltage tolerance (0–7 V) and 2 V–5.5 V VCC range eliminate level-shifter ICs and reduce BOM count.

Industrial I/O Expansion

Legacy Bus Interface

Use Scenario: Expanding digital I/O capability in PLC modules using parallel control buses with strict EMI requirements.

IC Role / Device Role / Timing Role: Cascaded decoder driving opto-isolator inputs with precise enable sequencing across multiple I/O banks.

Use Value: 2 kV HBM ESD rating and –55°C to +125°C operation ensure reliability in uncontrolled industrial environments.

Use Scenario: Interfacing modern microcontrollers to legacy ISA or PC/104 peripheral cards requiring 74LS238-compatible timing and pinout.

IC Role / Device Role / Timing Role: Drop-in replacement for obsolete 74LS238 with identical pin mapping and truth table behavior.

Use Value: Pin- and function-compatibility with 74-series reduces redesign effort; 5.5 ns tPD improves timing margin over LS-family's ~25 ns.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
SN74HC238N	Same logic function, 74HC speed grade; tPD = 17 ns (typ) at 5 V; no input overvoltage tolerance	Lower cost but unsuitable for mixed-voltage or hot-swap scenarios requiring 0–7 V input range	Prefer for cost-sensitive, single-supply 5 V systems where timing margin >15 ns is acceptable
74LVC238APW	3.3 V optimized; VCC = 1.65–3.6 V only; 3.5 ns tPD (typ); 5 V tolerant inputs	Cannot operate at 5 V VCC; requires external level shifters for 5 V output loads	Prefer for compact 3.3 V-only designs needing sub-5 ns delay and TSSOP footprint

Compared with SN74HC238N and 74LVC238APW, the 74VHC238MTR uniquely combines 5 V operation, 5.5 ns speed, 0–7 V input tolerance, and SO-16 legacy compatibility - making it optimal for retrofitting and mixed-voltage industrial controllers.

Availability

74VHC238MTR is available at Aetrix Electronics and suitable for memory address decoding, peripheral select logic, industrial I/O expansion, and legacy bus interface applications requiring stable component supply and long-term obsolescence mitigation.

Supply support for 74VHC238MTR 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, MCU, power, and discrete components for automotive, industrial, and consumer markets.

The 74VHC series targets high-speed, low-power logic applications requiring improved noise immunity and wider supply ranges than standard 74HC, especially in industrial and instrumentation systems demanding robustness across temperature and voltage extremes.

FAQ

Is 74VHC238MTR pin-compatible with 74LS238?

Yes - 74VHC238MTR uses identical SO-16 pinout and truth table as 74LS238, including A/B/C address inputs, G1/G2A/G2B enables, and Y0–Y7 outputs. No PCB redesign is needed for drop-in replacement, though VCC decoupling and fanout loading should be verified per VHC drive strength.

What is the maximum capacitive load this decoder can drive reliably?

The 74VHC238MTR is characterized up to 50 pF load capacitance in AC specs, with tPD increasing from 5.5 ns (15 pF) to 10.1 ns (50 pF) at 5 V. For stable operation beyond 50 pF, add series termination or buffer stages - especially in long-trace or multi-load configurations.

Can G2A and G2B be tied together for simplified enable control?

Yes - G2A and G2B are logically OR'd internally (both must be low to enable). Tying them together creates a single active-low enable input, reducing GPIO usage. Ensure combined net capacitance stays below 10 pF to avoid slowing enable transitions beyond timing budget.

Does this part support partial power-down with VCC = 0 V?

Yes - power-down protection allows all inputs to tolerate 0–7 V even with VCC = 0 V, preventing back-powering or latch-up. However, outputs enter high-impedance state only when VCC is applied and enables are inactive; with VCC = 0, outputs are undefined and must not be loaded.

74VHC238MTR Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: 74VHC

Package/Case:: 16-SOIC (0.154", 3.90mm Width)

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Type:: Decoder/Demultiplexer

Circuit:: 1 x 3:8

Independent Circuits:: 1

Current - Output High, Low:: 8mA, 8mA

Voltage Supply Source:: Single Supply

Voltage - Supply:: 2V ~ 5.5V

Operating Temperature:: -55°C ~ 125°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 16-SO

74VHC238MTR FAQ

1.How can I place an order for 74VHC238MTR through Aetrix?

Please submit a Request for Quotation (RFQ) for 74VHC238MTR on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for 74VHC238MTR reliable?

The price and inventory of 74VHC238MTR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74VHC238MTR is usually 5 days.

3.What payment methods are accepted for 74VHC238MTR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74VHC238MTR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 74VHC238MTR?

74VHC238MTR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 74VHC238MTR order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for 74VHC238MTR?

For technical support, including 74VHC238MTR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74VHC238MTR requirements.

6.How does Aetrix verify that 74VHC238MTR is sourced from the original manufacturer or authorized distributors?

All 74VHC238MTR products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that 74VHC238MTR meets industry standards.

7.What is the process for return or replacement of 74VHC238MTR?

All 74VHC238MTR units undergo pre-shipment inspection (PSI). If there is an issue with 74VHC238MTR, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The 74VHC238MTR part is unused and in its original packaging.

Return procedure for 74VHC238MTR:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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