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onsemi MC74LCX244MELG
- Part No.:
- MC74LCX244MELG
- Manufacturer:
- onsemi
- Package:
- 20-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
MC74LCX244MELG.pdf
- Description:
- IC BUF NON-INVERT 5.5V SOEIAJ-20
- Quantity:
- Payment:
- Shipping:
Inventory:1,809
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Product details
Overview
MC74LCX244MELG from onsemi is a low-voltage CMOS octal non-inverting 3-state buffer with 5 V-tolerant inputs and outputs, operating from 1.65 V to 5.5 V supply. It delivers ±24 mA output drive, supports live insertion/withdrawal, and features IOFF protection for high-impedance state when VCC = 0 V. It is used in memory address driving and TTL-level bus transceiver applications.
For engineers reviewing the MC74LCX244MELG datasheet, pinout, applications, or equivalent options, key selection factors include 5 V tolerance on all I/O pins, 24 mA balanced sink/source capability, sub-10 ns propagation delay at 3.3 V, IOFF compliance, and QFN20 (2.5×4.5 mm) package compatibility with high-density PCB layouts.
Technical Context
The MC74LCX244MELG implements dual 4-bit non-inverting buffer channels, each controlled by independent 3-state output enable (1OE, 2OE) inputs. Its input structure provides TTL-compatible thresholds across 1.65–5.5 V VCC while maintaining 5 V absolute maximum input voltage rating.
Output logic states are actively driven HIGH or LOW when enabled, and transition to true high-impedance (Z) under OE control - verified by IOFF leakage <10 µA at VCC = 0 V and VI = 5.5 V. Propagation delays (tPLH/tPHL) range from 5.9 ns (VCC = 4.5–5.5 V) to 10.3 ns (VCC = 1.65–1.95 V), with output enable/disable times ≤7.3 ns at full supply.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 1.65 V to 5.5 V - enables direct interface between 1.8 V, 2.5 V, 3.3 V, and 5 V logic domains without level shifters. |
| Input Voltage Max | −0.5 V to +6.5 V - guarantees safe operation when driven by legacy 5 V TTL sources. |
| Output Drive | ±24 mA - supports driving multiple LVTTL/LVCMOS loads or moderate-capacitance buses (e.g., 50 pF @ 3.3 V). |
| Propagation Delay | 5.9 ns max (VCC = 4.5–5.5 V) - ensures timing-critical bus buffering in high-speed memory and peripheral interfaces. |
| IOFF Leakage | <10 µA at VCC = 0 V - prevents back-powering and signal contention during hot-swap or power sequencing. |
| ESD Rating | >2000 V HBM - meets industrial-grade robustness requirements for board-level handling and system integration. |
| Quiescent ICC | 10 µA max - minimizes standby power in battery-backed or always-on subsystems. |
Pinout & Package
MC74LCX244MELG is packaged in a Pb-free, RoHS-compliant QFN20 (2.5 mm × 4.5 mm, 0.4 mm pitch) with exposed thermal pad (Case 485AA). Pin 1 is marked by dot or notch; package includes 20 I/O terminals and GND/VCC connections optimized for low-inductance, high-density routing.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | 1OE, 2OE | Active-Low output enable controls for first and second 4-bit buffer groups - HIGH disables outputs to high-Z. |
| 2, 4, 6, 8 | 1D0–1D3 | Data inputs for channel 1 - accept 1.65–5.5 V logic levels with TTL-compatible thresholds. |
| 3, 5, 7, 9 | 2O0–2O3 | Outputs for channel 2 - drive bidirectionally with ±24 mA capability and 5 V tolerance. |
| 12, 14, 16, 18 | 1O0–1O3 | Outputs for channel 1 - electrically identical to 2O0–2O3; share same VCC/GND rails. |
| 11, 13, 15, 17 | 2D0–2D3 | Data inputs for channel 2 - fully independent of channel 1; support mixed-voltage bus partitioning. |
| 10 | GND | Ground reference for all logic and I/O - must be connected to low-impedance system ground plane. |
| 20 | VCC | Primary supply rail - decoupling capacitor (≥100 nF) required within 3 mm of pin for noise suppression. |
| Exposed Pad | Thermal / GND | Internally tied to GND - soldered to PCB thermal pad for enhanced heat dissipation and EMI reduction. |
Key Features
| Feature | Design Value |
|---|---|
| 5 V Tolerant I/O | Enables direct connection to 5 V legacy systems without external level translators or clamping diodes. |
| Live Insertion Support | IOFF and high-impedance tri-state behavior prevent bus conflicts during hot-plug operations in modular backplanes. |
| Balanced ±24 mA Drive | Eliminates need for external pull-up/pull-down resistors in open-drain or bus-termination configurations. |
| Sub-10 µA Quiescent ICC | Reduces system-level static power by >99% compared to standard TTL buffers, critical for portable and IoT edge nodes. |
| Latchup Immunity | Exceeds 500 mA - ensures robust operation under transient overvoltage or ESD stress in noisy industrial environments. |
Applications
| Memory Address Buffering | Industrial Bus Transceiver |
|---|---|
Use Scenario: Driving address lines from a 3.3 V microcontroller to multiple 5 V SRAM chips on a shared memory bus. IC Role / Device Role / Timing Role: Non-inverting octal buffer providing level translation, fanout expansion, and noise isolation between controller and memory array. Use Value: Eliminates discrete level shifters; 5 V-tolerant inputs accept SRAM address strobes directly, while 24 mA drive ensures clean edges into 50 pF load. | Use Scenario: Isolating and buffering control signals between a 1.8 V FPGA I/O bank and a 5 V PLC I/O module via ribbon cable. IC Role / Device Role / Timing Role: Dual-channel 3-state buffer enabling bidirectional signal conditioning and hot-swap-safe bus arbitration. Use Value: IOFF protection prevents backfeeding during module insertion; tPZH/tPHZ <7.3 ns maintains deterministic timing in real-time control loops. |
| Hot-Swappable Backplane Interface | Low-Power Sensor Hub Aggregation |
Use Scenario: Interfacing a 2.5 V ARM-based CPU module to a legacy 5 V backplane carrying configuration and status signals. IC Role / Device Role / Timing Role: Voltage-agile octal buffer acting as a fault-isolated interface layer with independent OE control per channel. Use Value: Supports live insertion without disrupting active bus traffic; 10 µA ICC reduces idle power in always-on rack management subsystems. | Use Scenario: Aggregating digital outputs from eight 1.8 V environmental sensors into a single 3.3 V I²C-compatible data acquisition bus. IC Role / Device Role / Timing Role: Low-voltage buffer isolating sensor domain from host MCU, reducing capacitive loading and crosstalk. Use Value: 7 pF CIN minimizes signal distortion; 24 mA drive sustains rise/fall times <3 ns into 30 pF trace+load capacitance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LVC244APWR | Lower VCC min (1.65 V same), but only 24 mA sink / 24 mA source asymmetry; no IOFF spec. | Not qualified for hot-swap; requires external pull-downs if VCC off during operation. | Prefer MC74LCX244MELG where power sequencing or live insertion is required. |
| 74ALVC244MTCX | Wider VCC range (1.65–3.6 V), lower propagation delay (5.2 ns), but no 5 V tolerance - requires external clamping. | Restricted to sub-3.6 V systems; unsuitable for mixed-voltage 5 V legacy interfacing. | Choose MC74LCX244MELG when interfacing with 5 V peripherals or unregulated input sources. |
Compared with SN74LVC244APWR and 74ALVC244MTCX, the MC74LCX244MELG uniquely combines 5 V I/O tolerance, IOFF protection, and full 24 mA symmetric drive - making it the only option among the three qualified for industrial hot-swap and mixed-supply bus bridging without auxiliary components.
Availability
MC74LCX244MELG is available at Aetrix Electronics and suitable for memory address buffering, industrial bus transceivers, hot-swappable backplane interfaces, and low-power sensor hub aggregation requiring stable component supply and long-term lifecycle support.
Supply support for MC74LCX244MELG 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 delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.
The MC74LCX244MELG belongs to the LCX family of low-voltage CMOS logic devices designed specifically for mixed-voltage system interfacing, emphasizing 5 V tolerance, ultra-low static power, and robust hot-swap capability in space-constrained industrial and communications equipment.
FAQ
What is the maximum input voltage rating for MC74LCX244MELG?
The MC74LCX244MELG has a DC input voltage rating of −0.5 V to +6.5 V, allowing safe operation when driven by 5 V TTL logic even when powered from lower supplies like 1.8 V or 2.5 V. This 5 V tolerance eliminates the need for external clamping diodes or level-shifting circuitry in mixed-voltage designs, and is explicitly validated in the Absolute Maximum Ratings table of the official onsemi datasheet.
Does MC74LCX244MELG support hot-swap or live insertion?
Yes, MC74LCX244MELG supports live insertion and withdrawal due to its IOFF specification, which guarantees high-impedance outputs when VCC = 0 V (leakage <10 µA). This prevents back-powering or signal contention during hot-plug events in modular systems such as telecom line cards or industrial backplanes - a feature confirmed in the device's datasheet Features section and validated under JEDEC JESD78 latchup testing.
What package type is used for MC74LCX244MELG?
MC74LCX244MELG uses a Pb-free, RoHS-compliant QFN20 package measuring 2.5 mm × 4.5 mm with 0.4 mm pitch (Case 485AA). It includes an exposed thermal pad tied internally to GND, requiring soldering to a PCB thermal land for optimal thermal performance and EMI suppression - mechanical dimensions and footprint guidelines are provided in the official onsemi package drawing 98AON12653D.
What is the output drive strength of MC74LCX244MELG at 3.3 V supply?
At VCC = 3.3 V, MC74LCX244MELG delivers ±24 mA output drive in both sink and source directions, as specified in the DC Electrical Characteristics table. This balanced capability ensures clean signal integrity into typical bus loads (e.g., 50 pF), eliminates need for external pull resistors, and supports fanout to multiple LVTTL or LVCMOS inputs without degradation - verified across temperature (−55 °C to +125 °C) and process corners.
Is MC74LCX244MELG suitable for automotive applications?
The base MC74LCX244MELG is not AEC-Q100 qualified; however, the automotive-grade variant MC74LCX244DTR2G-Q (TSSOP-20) is explicitly listed as AEC-Q100 qualified and PPAP capable in the onsemi ordering information table. For automotive use, designers must select the −Q suffix part - the MC74LCX244MELG itself targets industrial, computing, and communications applications where extended temperature range (−55 °C to +125 °C) and robustness are required but formal automotive qualification is not mandated.
MC74LCX244MELG Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74LCX
- 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:
- 2V ~ 5.5V
- Operating Temperature:
- -55°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOEIAJ-20
MC74LCX244MELG FAQ
1.How can I place an order for MC74LCX244MELG through Aetrix?
Please submit a Request for Quotation (RFQ) for MC74LCX244MELG 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 MC74LCX244MELG reliable?
The price and inventory of MC74LCX244MELG are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC74LCX244MELG is usually 5 days.
3.What payment methods are accepted for MC74LCX244MELG?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC74LCX244MELG transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC74LCX244MELG?
MC74LCX244MELG orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC74LCX244MELG 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 MC74LCX244MELG?
For technical support, including MC74LCX244MELG datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC74LCX244MELG requirements.
6.How does Aetrix verify that MC74LCX244MELG is sourced from the original manufacturer or authorized distributors?
All MC74LCX244MELG 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 MC74LCX244MELG meets industry standards.
7.What is the process for return or replacement of MC74LCX244MELG?
All MC74LCX244MELG units undergo pre-shipment inspection (PSI). If there is an issue with MC74LCX244MELG, 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 MC74LCX244MELG part is unused and in its original packaging.
Return procedure for MC74LCX244MELG:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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