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Home > Products > Integrated Circuits (ICs) > Logic > Buffers, Drivers, Receivers, Transceivers

onsemi DM74ALS245AWMX

Name: DM74ALS245AWMX
Brand: onsemi
SKU: DM74ALS245AWMX
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: DM74ALS245AWMX

Manufacturer:: onsemi

Category:: Buffers, Drivers, Receivers, Transceivers

Package:: 20-SOIC (0.295", 7.50mm Width)

Datasheet:: DM74ALS245AWMX.pdf

Description:: IC TXRX NON-INVERT 5.5V 20SOIC

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Product details

Overview

DM74ALS245AWMX from Fairchild Semiconductor is an octal 3-STATE bus transceiver in a 20-lead SOIC (M20B) package, designed for bidirectional data transfer between asynchronous buses in microprocessor and memory systems. It features independent 3-STATE control on A and B ports, 5V supply operation (4.5–5.5V), propagation delays ≤10 ns, and output drive capability of ±24 mA (IOL)/−15 mA (IOH).

For engineers reviewing the DM74ALS245AWMX datasheet, pinout, applications, or equivalent options, key selection criteria include DIR/G-controlled bidirectional flow, high-impedance isolation timing (tPLZ ≤15 ns, tPHZ ≤10 ns), CMOS interface compatibility (VOH = VCC − 2V), and 500Ω/50 pF switching load specification.

Technical Context

The DM74ALS245AWMX implements dual 8-bit unidirectional buffers with separate direction (DIR) and output enable (G) controls, enabling synchronous bidirectional bus communication without internal contention. Its oxide-isolated, ion-implanted Schottky TTL process ensures stable operation across 0°C to +70°C and full VCC range (4.5–5.5V).

Each port supports independent 3-STATE control: G = LOW enables transceiver action (A↔B per DIR state), while G = HIGH forces all outputs into high-impedance mode regardless of DIR. PNP input structure minimizes input loading, and glitch-free behavior is guaranteed during power-up/down sequences.

Key Specifications

Parameter	Value and Actual Design Meaning
VCC Range	4.5 V to 5.5 V - Ensures compatibility with standard 5V TTL/CMOS logic rails and noise margin stability.
Propagation Delay	tPLH/tPHL ≤10 ns - Enables reliable operation in high-speed 8-bit bus systems up to ~50 MHz clock-equivalent rates.
Output Drive	IOL = 24 mA, IOH = −15 mA - Sufficient to drive terminated transmission lines (e.g., 133Ω) and standard TTL loads.
Input Compatibility	VIH = 2.0 V, VIL = 0.8 V - Directly interfaces with both TTL and CMOS logic families without level-shifting.
3-STATE Disable Time	tPHZ ≤10 ns, tPLZ ≤15 ns - Supports fast bus arbitration and multi-master timing in shared-data environments.
Switching Load	Specified at 500Ω/50 pF - Validates timing performance under realistic PCB trace + capacitance conditions.
Operating Temperature	0°C to +70°C - Qualified for commercial-grade embedded and industrial control applications.

Pinout & Package

DM74ALS245AWMX is housed in a 20-lead Small Outline Integrated Circuit (SOIC) package per JEDEC MS-013, 0.300" wide (Package Number M20B), with standard surface-mount footprint and thermal resistance θJA = 72.0°C/W.

Pin/Terminal	Circuit Role	Design Meaning
1 (G)	Output Enable	Active-low global 3-STATE control: G = LOW enables transceiver; G = HIGH disables all outputs to Hi-Z.
2 (A1)	Port A Input/Output	Bi-directional I/O terminal for first bit of A bus; direction determined by DIR state when G = LOW.
3 (A2)	Port A Input/Output	Bi-directional I/O terminal for second bit of A bus; electrically identical to A1–A8.
4 (A3)	Port A Input/Output	Third bit of A bus; shares same electrical specs and timing as other A-port pins.
5 (A4)	Port A Input/Output	Fourth bit of A bus; supports full 8-bit parallel transfer when enabled.
6 (A5)	Port A Input/Output	Fifth bit of A bus; no internal buffering or inversion - direct signal path.
7 (A6)	Port A Input/Output	Sixth bit of A bus; maintains consistent VIH/VIL thresholds across all A pins.
8 (A7)	Port A Input/Output	Seventh bit of A bus; compatible with 500Ω/50 pF test load for timing validation.
9 (A8)	Port A Input/Output	Eighth bit of A bus; completes full octal channel set on A side.
10 (GND)	Ground Reference	Common return path for all digital and power currents; must be low-impedance connection.
11 (B1)	Port B Input/Output	Bi-directional I/O terminal for first bit of B bus; mirrors A1 functionality with identical specs.
12 (B2)	Port B Input/Output	Second bit of B bus; supports simultaneous bidirectional flow when DIR selects direction.
13 (B3)	Port B Input/Output	Third bit of B bus; timing matched to A-side counterparts for skew-critical applications.
14 (B4)	Port B Input/Output	Fourth bit of B bus; driven by same internal Schottky TTL stage as all B pins.
15 (B5)	Port B Input/Output	Fifth bit of B bus; shares VOH/VOL specs: VOH ≥2.4 V @ −3 mA, VOL ≤0.5 V @ 24 mA.
16 (B6)	Port B Input/Output	Sixth bit of B bus; input current limited to ±0.1 mA max at control inputs, ±20 µA at VIH.
17 (B7)	Port B Input/Output	Seventh bit of B bus; supports CMOS interfacing via VOH = VCC − 2V specification.
18 (B8)	Port B Input/Output	Eighth bit of B bus; completes full octal channel set on B side.
19 (DIR)	Direction Control	Non-inverting control: DIR = LOW → B→A transfer; DIR = HIGH → A→B transfer; only active when G = LOW.
20 (VCC)	Supply Voltage	+5 V nominal supply rail; decoupling capacitor required near pin for noise suppression.

Key Features

Feature	Design Value
Advanced Schottky TTL Process	Oxide-isolated, ion-implanted fabrication ensures consistent parametric performance across temperature and voltage extremes.
Independent 3-STATE Control	G and DIR operate orthogonally: G disables outputs regardless of DIR, enabling safe bus isolation during arbitration.
Glitch-Free Power Sequencing	No spurious output transitions occur during power-up or power-down, preventing bus contention in mixed-rail systems.
Low Output Impedance	Capable of driving 133Ω terminated lines directly-reduces need for external line drivers in backplane designs.
CMOS Interface Compatibility	VOH spec of VCC − 2V guarantees interoperability with 5V CMOS devices without level-shifting circuitry.

Applications

Microprocessor Data Bus Extension	Memory Address/Data Multiplexing
Use Scenario: Extending 8-bit data paths between CPU and peripheral ICs across PCB layers or connectors where physical separation requires signal buffering and direction control. IC Role / Device Role / Timing Role: Bidirectional bus transceiver managing real-time A↔B data flow under CPU-generated DIR/G signals; provides sub-10 ns propagation delay for cycle-accurate timing. Use Value: Eliminates bus contention during read/write alternation and enables clean high-impedance isolation when peripherals are deselected.	Use Scenario: Separating time-multiplexed address and data signals on shared memory bus lines (e.g., Intel 8085/8086 systems). IC Role / Device Role / Timing Role: Direction-controlled repeater that latches and forwards address bits during setup phase, then switches to data transfer mode during read/write cycles. Use Value: Maintains signal integrity over longer traces and allows independent timing control of address vs. data phases using DIR/G sequencing.
Industrial PLC I/O Expansion	Legacy System Bus Isolation
Use Scenario: Interfacing modular I/O cards with main controller bus in programmable logic controllers where hot-swap and fault isolation are required. IC Role / Device Role / Timing Role: Isolation barrier with controlled 3-STATE activation; G input tied to module presence detection to prevent backfeeding during insertion/removal. Use Value: Prevents system-level bus corruption during field maintenance and supports deterministic recovery after module reconnection.	Use Scenario: Electrically isolating legacy 8-bit subsystems (e.g., UART, parallel printer ports) from modern host controllers to avoid ground loop or voltage mismatch issues. IC Role / Device Role / Timing Role: Level-translating buffer with Hi-Z disable capability; used to gate legacy bus access without modifying existing firmware or timing constraints. Use Value: Enables drop-in integration of older peripherals into newer designs while preserving original timing margins and signal fidelity.

Microprocessor Data Bus Extension

Memory Address/Data Multiplexing

Use Scenario: Extending 8-bit data paths between CPU and peripheral ICs across PCB layers or connectors where physical separation requires signal buffering and direction control.

IC Role / Device Role / Timing Role: Bidirectional bus transceiver managing real-time A↔B data flow under CPU-generated DIR/G signals; provides sub-10 ns propagation delay for cycle-accurate timing.

Use Value: Eliminates bus contention during read/write alternation and enables clean high-impedance isolation when peripherals are deselected.

Use Scenario: Separating time-multiplexed address and data signals on shared memory bus lines (e.g., Intel 8085/8086 systems).

IC Role / Device Role / Timing Role: Direction-controlled repeater that latches and forwards address bits during setup phase, then switches to data transfer mode during read/write cycles.

Use Value: Maintains signal integrity over longer traces and allows independent timing control of address vs. data phases using DIR/G sequencing.

Industrial PLC I/O Expansion

Legacy System Bus Isolation

Use Scenario: Interfacing modular I/O cards with main controller bus in programmable logic controllers where hot-swap and fault isolation are required.

IC Role / Device Role / Timing Role: Isolation barrier with controlled 3-STATE activation; G input tied to module presence detection to prevent backfeeding during insertion/removal.

Use Value: Prevents system-level bus corruption during field maintenance and supports deterministic recovery after module reconnection.

Use Scenario: Electrically isolating legacy 8-bit subsystems (e.g., UART, parallel printer ports) from modern host controllers to avoid ground loop or voltage mismatch issues.

IC Role / Device Role / Timing Role: Level-translating buffer with Hi-Z disable capability; used to gate legacy bus access without modifying existing firmware or timing constraints.

Use Value: Enables drop-in integration of older peripherals into newer designs while preserving original timing margins and signal fidelity.

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal bus transceiver applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
SN74ALS245N	Same ALS family, identical logic function and DC specs, but in PDIP (N20A) package instead of SOIC.	Preferred for through-hole prototyping or legacy board rework; lacks SOIC thermal and space advantages.	Select SN74ALS245N if manual soldering, breadboarding, or socket-based testing is required.
74F245SC	Fast TTL variant: faster propagation (≤6.5 ns), higher ICC (up to 90 mA), wider VCC tolerance (4.5–5.5 V), but no VOH = VCC − 2V CMOS compatibility guarantee.	Better suited for speed-critical backplanes; less ideal for mixed CMOS/TTL systems requiring guaranteed high-level interface margins.	Choose 74F245SC only when sub-7 ns timing dominates over power efficiency and CMOS interoperability.

Compared with SN74ALS245N and 74F245SC, the DM74ALS245AWMX delivers optimal balance of speed (≤10 ns), low power (ICC ≤58 mA), SOIC packaging for density, and explicit CMOS interface support-making it the preferred choice for space-constrained, mixed-logic commercial embedded systems.

Availability

DM74ALS245AWMX is available at Aetrix Electronics and suitable for microprocessor bus extension, memory multiplexing, industrial I/O expansion, and legacy system isolation requiring stable component supply and long-term obsolescence management.

Supply support for DM74ALS245AWMX 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

Fairchild Semiconductor was a U.S.-based semiconductor company specializing in analog and discrete power products, acquired by ON Semiconductor in 2016. Known for robust TTL, MOS, and power IC portfolios.

The DM74ALS245AWMX belongs to Fairchild's advanced low-power Schottky (ALS) logic family, engineered for high-speed, low-noise bidirectional data transfer in commercial-grade computing and control systems.

FAQ

What is the operating voltage range for the DM74ALS245AWMX?

The DM74ALS245AWMX operates over a recommended VCC range of 4.5 V to 5.5 V. This range ensures stable logic levels, meets TTL input thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V), and supports guaranteed switching performance into 500Ω/50 pF loads. Absolute maximum supply voltage is 7 V, but sustained operation outside 4.5–5.5 V voids parametric guarantees. The DM74ALS245AWMX is not rated for 3.3 V operation.

How does the DIR and G control logic work on the DM74ALS245AWMX?

On the DM74ALS245AWMX, G (pin 1) is the active-low output enable: when G = HIGH, all A and B port outputs enter high-impedance mode regardless of DIR. When G = LOW, DIR (pin 19) determines direction-DIR = LOW enables B→A transfer, DIR = HIGH enables A→B transfer. Both controls are fully static and valid across the full temperature range. The DM74ALS245AWMX does not support simultaneous bidirectional operation on the same pin pair.

Is the DM74ALS245AWMX compatible with CMOS logic levels?

Yes, the DM74ALS245AWMX is explicitly specified to interface with CMOS devices: its VOH is guaranteed to be ≥ VCC − 2 V (e.g., ≥3.0 V at VCC = 5.0 V), satisfying typical CMOS VIH minimums. Input thresholds (VIH = 2.0 V, VIL = 0.8 V) also align with 5V CMOS logic families. This compatibility is confirmed in the Electrical Characteristics table and applies directly to the DM74ALS245AWMX under recommended operating conditions.

What is the thermal resistance (θJA) of the DM74ALS245AWMX package?

As documented in the Fairchild DS006213 datasheet, the DM74ALS245AWMX in its 20-lead SOIC (M20B) package has a typical junction-to-ambient thermal resistance (θJA) of 72.0°C/W. This value assumes standard JEDEC 2-layer board mounting conditions and is critical for calculating maximum allowable power dissipation (e.g., 58 mA ICC × 5 V ≈ 290 mW → ΔT ≈ 20.9°C rise). The DM74ALS245AWMX does not include thermal pad or exposed die attach enhancements.

Does the DM74ALS245AWMX support hot-plug or live-insertion scenarios?

The DM74ALS245AWMX features glitch-free behavior during power-up and power-down, minimizing spurious outputs when VCC ramps. However, it lacks built-in bus-hold, power-off protection, or Ioff (power-off isolation) specifications. For true hot-plug use, external series resistors or dedicated hot-swap controllers are recommended. The DM74ALS245AWMX itself is not rated for live insertion into powered-backplane environments without supplemental protection circuitry.

DM74ALS245AWMX Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: 74ALS

Package/Case:: 20-SOIC (0.295", 7.50mm Width)

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Logic Type:: Transceiver, Non-Inverting

Number of Elements:: 1

Number of Bits per Element:: 8

Input Type:: -

Output Type:: 3-State

Current - Output High, Low:: 15mA, 24mA

Voltage - Supply:: 4.5V ~ 5.5V

Operating Temperature:: 0°C ~ 70°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 20-SOIC

DM74ALS245AWMX FAQ

1.How can I place an order for DM74ALS245AWMX through Aetrix?

Please submit a Request for Quotation (RFQ) for DM74ALS245AWMX 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 DM74ALS245AWMX reliable?

The price and inventory of DM74ALS245AWMX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DM74ALS245AWMX is usually 5 days.

3.What payment methods are accepted for DM74ALS245AWMX?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DM74ALS245AWMX transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for DM74ALS245AWMX?

DM74ALS245AWMX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your DM74ALS245AWMX 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 DM74ALS245AWMX?

For technical support, including DM74ALS245AWMX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DM74ALS245AWMX requirements.

6.How does Aetrix verify that DM74ALS245AWMX is sourced from the original manufacturer or authorized distributors?

All DM74ALS245AWMX 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 DM74ALS245AWMX meets industry standards.

7.What is the process for return or replacement of DM74ALS245AWMX?

All DM74ALS245AWMX units undergo pre-shipment inspection (PSI). If there is an issue with DM74ALS245AWMX, 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 DM74ALS245AWMX part is unused and in its original packaging.

Return procedure for DM74ALS245AWMX:

1.Submit a request within 90 days.

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

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