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onsemi 74LCX244WMX
- Part No.:
- 74LCX244WMX
- Manufacturer:
- onsemi
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
74LCX244WMX.pdf
- Description:
- IC BUFFER NON-INVERT 3.6V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:37,648
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Product details
Overview
74LCX244WMX from Fairchild Semiconductor is an octal non-inverting 3-STATE buffer/line driver designed for low-voltage bus interface between 2.3V–3.6V logic and 5V signal environments. It features 5V-tolerant inputs/outputs, 6.5ns max propagation delay at VCC = 3.3V, ±24mA output drive at 3.0V, and power-down high-impedance I/O. It is used in memory address driving, clock distribution, and bidirectional bus transceivers in industrial control backplanes.
For engineers reviewing the 74LCX244WMX datasheet, pinout, applications, or equivalent options, key selection criteria include 5V tolerance with 3.3V core operation, 20-pin SOIC-W package compatibility, 3-STATE enable control timing (tPZL/tPLZ ≤ 7.0ns), and latch-up immunity exceeding 500mA - critical for mixed-voltage board-level interconnects.
Technical Context
The 74LCX244WMX implements two independent 4-bit groups (OE1 controls I0–I3→O0–O3; OE2 controls I4–I7→O4–O7), each with separate 3-STATE enable inputs. Its advanced CMOS process enables rail-to-rail 5V-tolerant I/O while operating from a 2.3V–3.6V supply, eliminating level-shifter requirements in 3.3V systems interfacing to legacy 5V peripherals.
It supports live insertion/withdrawal via controlled high-impedance transitions during power sequencing - achieved by tying OE to VCC through a pull-up resistor per datasheet Note 1. Input leakage remains ≤±5.0µA across full voltage range, and dynamic switching skew is limited to 1.0ns between any two outputs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 2.3V to 3.6V - Enables direct use in 2.5V/3.3V systems without regulator overhead |
| Input/Output Voltage Tolerance | –0.5V to +7.0V - Allows safe connection to 5V buses without external clamping or translation |
| Propagation Delay (tPD) | 6.5ns max at VCC = 3.3V, CL = 50pF - Supports >100MHz bus toggle rates in address/data paths |
| Output Drive Strength | ±24mA at VCC = 3.0V - Drives 15pF loads across 15cm traces or 10+ TTL inputs with margin |
| 3-STATE Enable/Disable Time | tPZL/tPLZ ≤ 7.0ns at VCC = 3.3V - Ensures clean bus arbitration with minimal contention window |
| Quiescent ICC | 10µA max - Reduces standby power in battery-backed or energy-sensitive applications |
| Latch-up Immunity | >500mA - Meets JEDEC JESD78 Class II requirements for robustness in noisy industrial environments |
Pinout & Package
74LCX244WMX is housed in a 20-lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300" wide (M20B), with exposed pad not present. Pin 1 is marked by notch or bevel; pin numbering follows standard SOIC convention (counterclockwise from top-left).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | GND | Ground reference for all I/O and internal logic - must be low-inductance connection to PCB ground plane |
| 20, 10 | VCC | Primary power supply (2.3V–3.6V) - requires local 0.1µF ceramic decoupling adjacent to pin |
| 12, 14, 16, 18 | OE1 | Group 1 3-STATE enable - active LOW; controls O0–O3; tied HIGH via pull-up for hot-swap safety |
| 3, 5, 7, 9 | OE2 | Group 2 3-STATE enable - active LOW; controls O4–O7; independent timing from OE1 |
| 2, 4, 6, 8 | I0–I3 | Group 1 inputs - accept 0–5.5V signals; internally clamped to VCC/GND |
| 11, 13, 15, 17 | I4–I7 | Group 2 inputs - electrically identical to I0–I3; supports split-bus addressing |
| 18, 16, 14, 12 | O0–O3 | Group 1 buffered outputs - non-inverting, 3-STATE, 5V-tolerant, ±24mA capable |
| 9, 7, 5, 3 | O4–O7 | Group 2 buffered outputs - mirrored pinout symmetry simplifies PCB layout routing |
Key Features
| Feature | Design Value |
|---|---|
| 5V-tolerant I/O on 3.3V supply | Eliminates discrete level shifters in mixed-voltage systems - reduces BOM count and layout area |
| Power-down high-impedance I/O | Ensures bus isolation during power sequencing or sleep modes - prevents back-driving and current leakage |
| Live insertion/withdrawal support | Enables hot-plug capability in modular backplanes without system reset or data corruption |
| ±24mA output drive at 3.0V | Drives standard 50Ω transmission lines or multiple TTL loads without external buffers |
| Latch-up immunity >500mA | Guarantees operation in electrically noisy industrial settings with ESD or transient coupling |
Applications
| Memory Address Buffering | Industrial Backplane Interface |
|---|---|
Use Scenario: Driving 16-bit address bus from a 3.3V microcontroller to multiple 5V SRAM chips in programmable logic controllers. IC Role / Device Role / Timing Role: Non-inverting buffer with 3-STATE control isolating CPU from memory during DMA cycles. Use Value: 6.5ns tPD ensures setup/hold timing compliance at 25MHz bus clocks; 5V tolerance avoids level-shifter design complexity. |
Use Scenario: Interfacing 3.3V FPGA I/O banks to legacy 5V peripheral modules in modular automation racks. IC Role / Device Role / Timing Role: Bidirectional bus transceiver enabling hot-swappable module detection and configuration. Use Value: Live insertion support and power-down high-Z prevent bus contention during module replacement; ±24mA drive sustains signal integrity over 20cm backplane traces. |
| Embedded Clock Distribution | Legacy Peripheral Bridge |
Use Scenario: Distributing a 3.3V system clock to multiple 5V real-time clock (RTC) and watchdog ICs in medical monitoring equipment. IC Role / Device Role / Timing Role: Low-skew clock buffer with independent enable control per output group for power-gated domains. Use Value: 1.0ns max output-to-output skew maintains clock phase alignment across subsystems; 10µA ICC minimizes standby current draw. |
Use Scenario: Connecting a 3.3V ARM processor GPIO bank to 5V industrial I/O expanders (e.g., PCF8574) via I²C-compatible control lines. IC Role / Device Role / Timing Role: Voltage-tolerant line driver translating control signals while preserving logic thresholds. Use Value: VIH/VIL specs (2.0V/0.8V at VCC=3.3V) ensure noise-immune recognition of 5V pull-ups; input leakage ≤±5µA prevents false triggering. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 74LVC244APW,118 (Nexperia) | Same 20-pin TSSOP package; 1.65V–3.6V VCC range; 5V-tolerant I/O; 3.7ns tPD at 3.3V | Higher speed but lower drive (±24mA only at VCC ≥ 3.0V); no DQFN option | Select when faster propagation delay is required and TSSOP footprint is acceptable |
| SN74LVC244ADWR (TI) | 20-pin SOIC-W package; 1.65V–3.6V VCC; 5V-tolerant I/O; 4.2ns tPD at 3.3V; higher ICC (max 10µA vs. 10µA same) | Identical SOIC-W mechanical fit; tighter VOH/VOL specs; no live-insertion note in datasheet | Select for drop-in replacement where enhanced DC output specs are prioritized over hot-swap assurance |
Compared with 74LCX244WMX, the Nexperia 74LVC244APW offers superior speed but lacks documented live insertion support, while TI's SN74LVC244ADWR matches the SOIC-W footprint and improves DC output voltage margins - both require validation of OE timing and power-up sequencing in hot-swap contexts.
Availability
74LCX244WMX is available at Aetrix Electronics and suitable for industrial control backplanes, embedded memory interfaces, FPGA peripheral bridging, and medical device clock distribution requiring stable component supply across extended temperature ranges (–40°C to +85°C).
Supply support for 74LCX244WMX 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 leading designer of high-performance analog and mixed-signal semiconductors, acquired by ON Semiconductor in 2016; its legacy logic portfolio remains widely deployed in industrial and automotive systems.
The 74LCX family was engineered for low-voltage, high-speed bus interfacing in mixed-signal systems - specifically targeting 3.3V/2.5V logic domains needing seamless interoperability with 5V legacy infrastructure.
FAQ
What is the maximum operating supply voltage for the 74LCX244WMX?
The 74LCX244WMX supports a recommended VCC range of 2.3V to 3.6V for normal operation. Its absolute maximum rating is +7.0V, but operation above 3.6V violates recommended conditions and risks parametric degradation. The device is optimized for 3.3V systems, delivering specified tPD, drive strength, and noise immunity within this band. Always maintain VCC within 2.3V–3.6V during active use of 74LCX244WMX.
Does the 74LCX244WMX support hot-plug operation, and how is it implemented?
Yes, the 74LCX244WMX supports live insertion/withdrawal per datasheet Note 1. This is achieved by ensuring OE inputs enter high-impedance state during power-up/down - implemented by tying OE1 and OE2 to VCC via external pull-up resistors. The minimum resistor value depends on the driver's sourcing capability, but typical values range from 4.7kΩ to 10kΩ. This guarantees outputs remain in 3-STATE until VCC stabilizes, preventing bus contention. The 74LCX244WMX relies on this external circuitry - not internal logic - for hot-swap safety.
What is the meaning of "5V tolerant" for the 74LCX244WMX inputs and outputs?
"5V tolerant" means the 74LCX244WMX inputs and outputs can safely withstand DC voltages from –0.5V to +7.0V regardless of VCC level, without damage or functional disruption. When VCC = 3.3V, the device correctly interprets 0–5.5V input signals as valid logic HIGH/LOW and drives output voltages compatible with 5V TTL/CMOS loads. This eliminates need for external level translators in mixed-voltage designs - a key feature confirmed in the General Description and Absolute Maximum Ratings sections of the 74LCX244WMX datasheet.
How many independent 3-STATE control inputs does the 74LCX244WMX have?
The 74LCX244WMX has two independent 3-STATE enable inputs: OE1 (pins 12, 14, 16, 18) controls outputs O0–O3, and OE2 (pins 3, 5, 7, 9) controls outputs O4–O7. Each group operates independently, allowing partial bus gating - for example, holding O0–O3 active while tri-stating O4–O7 during multiplexed address/data transfers. This dual-enable architecture is explicitly defined in the Pin Description and Truth Tables of the 74LCX244WMX datasheet.
What package type is used for the 74LCX244WMX, and is it lead-free?
The 74LCX244WMX uses a 20-lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300" wide (package code M20B). It is lead-free and complies with JEDEC J-STD-020B standard, as confirmed in the Ordering Information section. The "WM" suffix denotes this SOIC-W variant, and the "X" suffix indicates tape-and-reel packaging. No exposed thermal pad is present - unlike the DQFN variant (74LCX244BQX) - making it compatible with standard SOIC reflow profiles.
74LCX244WMX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74LCX
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Bulk
- Product Status:
- Active
- 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 ~ 3.6V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
74LCX244WMX FAQ
1.How can I place an order for 74LCX244WMX through Aetrix?
Please submit a Request for Quotation (RFQ) for 74LCX244WMX 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 74LCX244WMX reliable?
The price and inventory of 74LCX244WMX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74LCX244WMX is usually 5 days.
3.What payment methods are accepted for 74LCX244WMX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74LCX244WMX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74LCX244WMX?
74LCX244WMX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74LCX244WMX 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 74LCX244WMX?
For technical support, including 74LCX244WMX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74LCX244WMX requirements.
6.How does Aetrix verify that 74LCX244WMX is sourced from the original manufacturer or authorized distributors?
All 74LCX244WMX 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 74LCX244WMX meets industry standards.
7.What is the process for return or replacement of 74LCX244WMX?
All 74LCX244WMX units undergo pre-shipment inspection (PSI). If there is an issue with 74LCX244WMX, 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 74LCX244WMX part is unused and in its original packaging.
Return procedure for 74LCX244WMX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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