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onsemi MM74HCT244SJX
- Part No.:
- MM74HCT244SJX
- Manufacturer:
- onsemi
- Package:
- 20-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
MM74HCT244SJX.pdf
- Description:
- IC BUFFER NON-INVERT 5.5V 20SOP
- Quantity:
- Payment:
- Shipping:
Inventory:12,000
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Product details
Overview
MM74HCT244SJX from Fairchild Semiconductor is a non-inverting octal 3-STATE buffer IC designed for bidirectional bus interface and data routing in TTL-CMOS mixed-signal systems. It features two independent active-low enables (1G, 2G), 6 mA minimum output drive per pin, 14 ns typical propagation delay at 5 V/45 pF, and TTL-compatible inputs. It operates across –40°C to +85°C and is used in industrial control backplanes and memory address/data bus drivers.
For engineers reviewing the MM74HCT244SJX datasheet, pinout, applications, or equivalent options, key selection criteria include 3-STATE timing (tPZL/tPHZ), output drive capability under bus loading, enable-controlled channel isolation, and SOIC-20 footprint compatibility with legacy LS-TTL layouts.
Technical Context
The MM74HCT244SJX implements eight non-inverting buffer channels split into two groups of four, each controlled by its own active-low enable (1G, 2G). All outputs enter high-impedance state when their respective enable is HIGH, enabling shared-bus arbitration without external logic.
It uses silicon-gate CMOS process with TTL-level input thresholds (VIH = 2.0 V, VIL = 0.8 V), supports 5 V ±10% supply, and achieves LS-TTL speed (14 ns typ. tPLH/tPHL) while drawing only 4.0 µA quiescent ICC at 25°C - enabling direct drop-in replacement in power-sensitive upgrades of 74LS244-based designs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Function | Non-inverting octal buffer with dual 4-channel 3-STATE control |
| Propagation Delay | 14 ns typical (VCC = 5 V, CL = 45 pF), defines max clock/data rate in synchronous bus interfaces |
| Output Drive | 6 mA min sink/source per pin, sufficient to drive 15 LS-TTL loads or 45 pF bus capacitance at full speed |
| Enable Timing | tPZL/tPHZ = 20 ns max (CL = 45 pF), ensures clean bus release before next driver activation |
| Supply Range | 4.5–5.5 V, compatible with standard 5 V TTL/CMOS rails and tolerant of ripple up to ±10% |
| Operating Temp | –40°C to +85°C, qualified for industrial ambient environments without derating |
| Input Compatibility | TTL-level thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V), eliminates need for level-shifting when interfacing 74LS/74F families |
Pinout & Package
MM74HCT244SJX is housed in a 20-lead Small Outline Package (SOP), EIAJ TYPE II, 5.3 mm wide (Package Number M20D), with 1.27 mm pitch and gull-wing leads.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1G | Active-low enable for Y1–Y4 | Drives all four outputs (Y1–Y4) into high-Z when HIGH; enables buffering when LOW |
| 2G | Active-low enable for Y5–Y8 | Independent control of second group; allows interleaved or segmented bus access |
| 1A–4A | Non-inverting inputs for first group | Directly pass logic states to Y1–Y4 when 1G = LOW |
| 5A–8A | Non-inverting inputs for second group | Directly pass logic states to Y5–Y8 when 2G = LOW |
| Y1–Y8 | 3-STATE buffered outputs | Drive bus lines actively or disconnect completely (Z-state) to prevent contention |
| VCC | Positive supply | 5 V nominal; powers internal logic and output stages |
| GND | Ground reference | Common return for inputs, outputs, and supply current |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent enables | Enables selective activation of two 4-bit segments-critical for partial bus updates or memory-mapped I/O partitioning |
| High-output drive (6 mA) | Supports driving long PCB traces or multiple LS-TTL inputs without external buffers, reducing BOM count |
| Low quiescent current (4.0 µA) | Reduces standby power in always-on control modules; enables use in low-power industrial gateways |
| TTL-compatible inputs | Eliminates level translators when upgrading 74LS244 circuits-no logic redesign required |
| 3-STATE bus interface | Allows connection to shared data/address buses without contention; essential for multi-master systems |
Applications
| Industrial PLC Backplane Interface | Memory Address Bus Driver |
|---|---|
Use Scenario: Driving parallel I/O expansion slots in programmable logic controllers where multiple modules share a common data bus. IC Role / Device Role / Timing Role: Non-inverting buffer with per-group enable control isolates module-specific address/data traffic and prevents bus contention during hot-swap events. Use Value: Dual enables allow staggered activation of I/O banks, while 14 ns propagation delay supports 30+ MHz bus cycles in deterministic scan-based architectures. | Use Scenario: Buffering CPU-generated address signals to SRAM or EPROM chips on embedded controller boards. IC Role / Device Role / Timing Role: Octal non-inverting driver strengthens weak microcontroller address pins and provides bus isolation during DMA transfers. Use Value: 6 mA output drive ensures signal integrity across 10 cm traces; 3-STATE operation permits shared address decoding with peripheral select logic. |
| Legacy LS-TTL System Upgrade | Test Equipment Signal Routing |
Use Scenario: Replacing obsolete 74LS244 in aging test fixtures and instrumentation where power reduction and reliability are critical. IC Role / Device Role / Timing Role: Pin-compatible functional replacement delivering identical logic behavior with lower ICC and improved noise immunity. Use Value: Quiescent current reduced from ~19 mA (74LS244) to 4 µA - cuts system standby power by >99.9%, extending fixture uptime between maintenance cycles. | Use Scenario: Routing digital stimulus and response signals between FPGA-based pattern generators and DUT interface boards. IC Role / Device Role / Timing Role: Bidirectional bus switch emulator using enable-controlled directionality and fast 3-STATE transitions. Use Value: 20 ns max enable/disable time (tPZL/tPHZ) enables sub-50 ns signal path reconfiguration - essential for high-speed boundary-scan and JTAG test sequences. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal non-inverting buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HCT244N | Same logic function, identical AC/DC specs, but in PDIP-20 (N20A) package instead of SOP-20 | Suitable for through-hole prototyping or legacy board rework; lacks surface-mount thermal performance | Select when manual soldering or socket-based validation is required |
| 74VHC244M | Higher speed (tPD = 7.5 ns typ), wider VCC range (2–5.5 V), but lower drive (±8 mA) and no guaranteed LS-TTL input compatibility | Better for mixed-voltage 3.3 V/5 V systems; not drop-in for strict TTL-input legacy designs | Choose for new designs prioritizing speed and voltage flexibility over backward compatibility |
Compared with SN74HCT244N and 74VHC244M, the MM74HCT244SJX offers optimal balance of proven industrial reliability, SOP-20 surface-mount compatibility, and guaranteed TTL input thresholds - making it the preferred choice for cost-sensitive, high-volume upgrades of existing 74LS244-based systems.
Availability
MM74HCT244SJX is available at Aetrix Electronics and suitable for industrial PLC backplanes, memory address bus drivers, and legacy LS-TTL system upgrades requiring stable component supply and long-term lifecycle support.
Supply support for MM74HCT244SJX 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; its HCT logic family remains widely deployed in industrial and automotive systems.
The MM74HCT244SJX belongs to the MM74HCT high-speed CMOS logic series, engineered specifically to bridge TTL and CMOS domains with LS-TTL speed, CMOS power efficiency, and robust input compatibility.
FAQ
What is the operating voltage range for MM74HCT244SJX?
The MM74HCT244SJX operates over a supply voltage range of 4.5 V to 5.5 V, with full DC and AC specifications guaranteed across this window. This 5 V ±10% tolerance accommodates typical power rail variations in industrial control systems and ensures reliable interoperability with legacy TTL logic families without external regulation.
Does MM74HCT244SJX support true bidirectional data flow?
No, the MM74HCT244SJX is a unidirectional non-inverting buffer - signals flow only from A inputs to Y outputs. True bidirectionality requires external control logic or a dedicated transceiver like the 74HCT245. However, its dual active-low enables (1G, 2G) allow time-multiplexed use of the same physical bus lines for different data paths.
What is the maximum capacitive load MM74HCT244SJX can drive while maintaining specified timing?
The MM74HCT244SJX guarantees 14 ns typical propagation delay with a 45 pF load. At 150 pF, propagation delay increases to 28 ns (max), and enable/disable times extend to 42–63 ns. For designs exceeding 50 pF, layout optimization (shorter traces, ground planes) or adding local decoupling near the MM74HCT244SJX is recommended to maintain timing margins.
Is MM74HCT244SJX pin-compatible with the 74LS244?
Yes, the MM74HCT244SJX shares identical pinout and logic function with the 74LS244, including dual active-low enables and octal non-inverting buffering. This allows direct PCB replacement in most cases - though designers must verify that the SOP-20 footprint matches the original package and that thermal dissipation requirements are met.
What does the 'SJ' suffix indicate in MM74HCT244SJX?
The 'SJ' suffix in MM74HCT244SJX denotes the Small Outline Package (SOP), EIAJ TYPE II, 5.3 mm wide, with gull-wing leads. The trailing 'X' indicates tape-and-reel packaging for automated SMT assembly. This distinguishes it from PDIP ('N'), SOIC ('WM'), and TSSOP ('MTC') variants of the same device.
MM74HCT244SJX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74HCT
- Package/Case:
- 20-SOIC (0.209", 5.30mm 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:
- 7.2mA, 7.2mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOP
MM74HCT244SJX FAQ
1.How can I place an order for MM74HCT244SJX through Aetrix?
Please submit a Request for Quotation (RFQ) for MM74HCT244SJX 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 MM74HCT244SJX reliable?
The price and inventory of MM74HCT244SJX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MM74HCT244SJX is usually 5 days.
3.What payment methods are accepted for MM74HCT244SJX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MM74HCT244SJX transactions.
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4.How is shipping managed for MM74HCT244SJX?
MM74HCT244SJX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MM74HCT244SJX 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 MM74HCT244SJX?
For technical support, including MM74HCT244SJX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MM74HCT244SJX requirements.
6.How does Aetrix verify that MM74HCT244SJX is sourced from the original manufacturer or authorized distributors?
All MM74HCT244SJX 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 MM74HCT244SJX meets industry standards.
7.What is the process for return or replacement of MM74HCT244SJX?
All MM74HCT244SJX units undergo pre-shipment inspection (PSI). If there is an issue with MM74HCT244SJX, 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 MM74HCT244SJX part is unused and in its original packaging.
Return procedure for MM74HCT244SJX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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