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onsemi MC74ACT244MELG
- Part No.:
- MC74ACT244MELG
- Manufacturer:
- onsemi
- Package:
- 20-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
MC74ACT244MELG.pdf
- Description:
- IC BUFF NON-INVERT 5.5V SOEIAJ20
- Quantity:
- Payment:
- Shipping:
Inventory:4,317
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Product details
Overview
MC74ACT244MELG from onsemi is an octal 3-state buffer/line driver with TTL-compatible inputs, designed for memory address driving, clock distribution, and bidirectional bus interfacing in industrial control and embedded systems. It operates at 4.5–5.5 V, delivers ±24 mA output drive, features 9.0 ns max propagation delay at 5 V, and supports −40°C to +85°C ambient operation.
For engineers reviewing the MC74ACT244MELG datasheet, pinout, applications, or equivalent options, this page provides verified electrical specifications, SOIC-20W package details, truth table behavior, thermal limits, and validated alternative options for bus interface design.
Technical Context
The MC74ACT244MELG implements two independent 4-bit non-inverting buffers, each controlled by a dedicated 3-state enable (OE1/OE2). Its TTL-compatible inputs accept 0.8 V (VIL) and 2.0 V (VIH) thresholds at 5 V supply, enabling direct interfacing with legacy logic families without level translation.
Each output drives up to ±24 mA while maintaining VOL ≤ 0.44 V and VOH ≥ 4.4 V under load, and exhibits tPZH/tPLZ disable times ≤ 10.5 ns - critical for high-speed bus arbitration and glitch-free state transitions in synchronous data paths.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5–5.5 V - ensures compatibility with standard 5 V TTL and CMOS systems without regulation overhead |
| Output Drive | ±24 mA - sufficient to drive 50 Ω transmission lines or fan-out to 10+ LS-TTL loads |
| Propagation Delay | ≤9.0 ns (tPLH/tPHL @ 5 V, CL = 50 pF) - enables reliable operation in 100 MHz bus cycles |
| 3-State Enable Time | ≤8.5 ns (tPZH @ 5 V) - minimizes bus contention window during direction switching |
| Input Thresholds | VIL = 0.8 V, VIH = 2.0 V - guarantees robust noise margin and interoperability with 5 V TTL outputs |
| Operating Temperature | −40°C to +85°C - qualified for industrial-grade embedded and automation applications |
| ESD Rating | HBM > 2000 V - provides baseline handling robustness in manufacturing and field service |
Pinout & Package
MC74ACT244MELG is housed in a 20-lead SOIC wide-body (SOIC-20W) package per case 751D, with 1.27 mm pitch, 12.8 mm × 7.5 mm body size, and Pb-free (RoHS-compliant) finish.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 4, 6, 12, 14, 16, 18 | Input (A1–A4, B1–B4) | Non-inverting data inputs for two independent 4-bit channels |
| 3, 5, 7, 9, 13, 15, 17, 19 | Output (Y1–Y4, Z1–Z4) | 3-state buffered outputs; high-impedance when OE asserted |
| 11, 20 | OE1, OE2 | Active-low enables for Channel A (pins 12/14/16/18 → 13/15/17/19) and Channel B (pins 1/2/4/6 → 3/5/7/9) |
| 10 | GND | Ground reference for all I/O and internal logic |
| 20 | VCC | Positive supply rail (4.5–5.5 V); decoupling required within 1 cm of pin |
Key Features
| Feature | Design Value |
|---|---|
| TTL-Compatible Inputs | VIH = 2.0 V, VIL = 0.8 V at VCC = 5 V - eliminates need for external level shifters when interfacing with legacy microcontrollers or FPGAs |
| High-Drive 3-State Outputs | ±24 mA sink/source capability with VOL ≤ 0.44 V - supports direct connection to unterminated PCB traces or multiple downstream loads |
| Low Propagation Skew | tPLH/tPHL matching ≤ 1.5 ns across all 8 outputs - preserves timing integrity in parallel address/data buses |
| Pb-Free & RoHS Compliant | Meets J-STD-609 Category 3 moisture sensitivity (MSL Level 1) - supports standard reflow profiles without baking |
| Bus-Friendly Enable Architecture | Dual independent OE pins (OE1/OE2) - allows simultaneous or staggered channel control for half-duplex or time-multiplexed bus sharing |
Applications
| Memory Address Buffering | Microcontroller Bus Interface |
|---|---|
|
Use Scenario: Driving 16-bit address lines from a microcontroller to SRAM or Flash memory in an industrial PLC. IC Role / Device Role / Timing Role: Non-inverting 3-state buffer isolating MCU address bus from memory device, enabling shared bus access with DMA controllers. Use Value: ±24 mA drive ensures full-swing signal integrity over 10 cm PCB traces; dual OE pins allow precise timing control during memory read/write cycles. |
Use Scenario: Interfacing an 8-bit MCU with external peripherals via a multiplexed data/address bus. IC Role / Device Role / Timing Role: Bidirectional bus transceiver (configured as unidirectional driver) managing data flow between MCU port and peripheral registers. Use Value: 9.0 ns max propagation delay meets 10 MHz bus timing budgets; TTL-compatible inputs eliminate level-shifter components. |
| Industrial Clock Distribution | Legacy System Signal Conditioning |
|
Use Scenario: Distributing a 25 MHz system clock to multiple FPGA configuration ICs and ADC sampling clocks. IC Role / Device Role / Timing Role: Low-skew clock buffer with 3-state capability for dynamic clock gating and domain isolation. Use Value: Output disable time ≤10.5 ns prevents clock glitches during power-state transitions; matched delays preserve phase alignment across 8 outputs. |
Use Scenario: Upgrading aging instrumentation hardware using 74LS logic with modern 5 V CMOS-compatible components. IC Role / Device Role / Timing Role: Drop-in replacement for obsolete 74LS244, providing higher speed and lower power without board redesign. Use Value: Identical pinout and TTL input thresholds ensure zero-change integration; 50% lower ICC vs. LS family reduces thermal load in sealed enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal 3-state buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ACT244N | Same logic function, identical DC/AC specs, but in PDIP-20 package (longer lead inductance, higher thermal resistance) | Suitable for prototyping or through-hole assembly; not recommended for high-frequency (>20 MHz) or thermally constrained layouts | Select SN74ACT244N only when manual soldering or socket-based validation is required; SOIC-20W (MC74ACT244MELG) preferred for production. |
| 74VHC244N | CMOS-input variant (VIH = 3.5 V min), lower ICC (2 μA typ), but reduced output drive (±8 mA) and slower propagation (11 ns max) | Better for low-power battery-operated systems where speed < 5 MHz and drive < 10 mA suffice | Choose 74VHC244N only if power budget is < 1 mW per channel and bus loading is light; MC74ACT244MELG remains optimal for industrial bus drive. |
Compared with SN74ACT244N and 74VHC244N, MC74ACT244MELG uniquely combines TTL compatibility, ±24 mA drive, and SOIC-20W thermal performance - making it the preferred choice for noise-immune, high-fanout industrial bus interfaces requiring no layout changes.
Availability
MC74ACT244MELG is available at Aetrix Electronics and suitable for industrial control systems, embedded instrumentation, and legacy system upgrades requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.
Supply support for MC74ACT244MELG 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
onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient silicon solutions for automotive, industrial, cloud, and IoT applications.
The MC74ACT244MELG belongs to onsemi's 74ACT logic family - engineered for high-speed, TTL-compatible interfacing in industrial and communications infrastructure where reliability and signal integrity are critical.
FAQ
What is the maximum operating voltage for MC74ACT244MELG?
The MC74ACT244MELG has a recommended supply voltage range of 4.5 V to 5.5 V. Its absolute maximum rating is 6.5 V, but operation above 5.5 V violates the Recommended Operating Conditions and risks parametric degradation or latch-up. For stable 5 V system integration, MC74ACT244MELG must be powered within 4.5–5.5 V.
Does MC74ACT244MELG support hot insertion or live bus swapping?
No, MC74ACT244MELG does not include hot-swap protection circuitry. Its inputs and outputs are not designed for backdrive tolerance during live insertion. The device requires power to be stable before applying signals, and OE must be held inactive (high) during power-up to prevent bus contention. Use external series resistors or dedicated hot-swap controllers if live insertion is required.
What is the meaning of "MELG" in MC74ACT244MELG?
The suffix "MELG" denotes a specific packaging and compliance variant: "ME" indicates SOIC-20W (wide-body) package per case 751D, "L" signifies tape-and-reel packaging, and "G" confirms Pb-free (RoHS-compliant) construction. This matches the ordering code MC74ACT244DWR2G in onsemi's datasheet, confirming MC74ACT244MELG is a Pb-free SOIC-20W tape-and-reel product.
Can MC74ACT244MELG drive a 50 Ω transmission line directly?
Yes, MC74ACT244MELG can drive a 50 Ω line under DC conditions: its ±24 mA output current supports a 2.5 V swing into 50 Ω (V = I × R = 0.024 × 50 = 1.2 V), and VOH/VOL specs remain valid at that load. However, for AC integrity above 10 MHz, proper termination (e.g., source-series or parallel) and controlled impedance routing are still required to suppress reflections.
Is MC74ACT244MELG pin-compatible with MC74AC244MELG?
Yes, MC74ACT244MELG is pin-compatible with MC74AC244MELG - both share identical SOIC-20W pinout, terminal functions, and mechanical footprint. The key difference lies in input threshold compatibility: MC74ACT244MELG accepts TTL-level inputs (VIH = 2.0 V), while MC74AC244MELG requires CMOS-level inputs (VIH = 3.15 V at 4.5 V). Swapping them requires verifying upstream driver voltage levels.
MC74ACT244MELG Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74ACT
- Package/Case:
- 20-SOIC (0.209", 5.30mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Logic Type:
- Buffer, Non-Inverting
- Number of Elements:
- 2
- Number of Bits per Element:
- 4
- Input Type:
- -
- Output Type:
- 3-State
- Current - Output High, Low:
- 24mA, 24mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOEIAJ-20
MC74ACT244MELG FAQ
1.How can I place an order for MC74ACT244MELG through Aetrix?
Please submit a Request for Quotation (RFQ) for MC74ACT244MELG 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 MC74ACT244MELG reliable?
The price and inventory of MC74ACT244MELG are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC74ACT244MELG is usually 5 days.
3.What payment methods are accepted for MC74ACT244MELG?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC74ACT244MELG transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC74ACT244MELG?
MC74ACT244MELG orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC74ACT244MELG 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 MC74ACT244MELG?
For technical support, including MC74ACT244MELG datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC74ACT244MELG requirements.
6.How does Aetrix verify that MC74ACT244MELG is sourced from the original manufacturer or authorized distributors?
All MC74ACT244MELG 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 MC74ACT244MELG meets industry standards.
7.What is the process for return or replacement of MC74ACT244MELG?
All MC74ACT244MELG units undergo pre-shipment inspection (PSI). If there is an issue with MC74ACT244MELG, 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 MC74ACT244MELG part is unused and in its original packaging.
Return procedure for MC74ACT244MELG:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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