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STMicroelectronics M74HC244B1R
- Part No.:
- M74HC244B1R
- Manufacturer:
- STMicroelectronics
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
M74HC244B1R.pdf
- Description:
- IC BUFFER NON-INVERT 6V 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,176
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Product details
Overview
M74HC244B1R from STMicroelectronics is an octal non-inverting 3-state bus buffer IC used for bidirectional data routing and memory address driving in digital systems. It features 20-pin DIP packaging, operates from 2V to 6V, delivers symmetrical 6mA output drive (|IOH| = IOL), exhibits 10ns typical propagation delay at 6V, and supports industrial temperature range (–55°C to +125°C).
For engineers reviewing the M74HC244B1R datasheet, M74HC244B1R pinout, M74HC244B1R application, or M74HC244B1R equivalent, key selection criteria include 3-state enable timing (tPZL/tPLZ ≤ 32ns at 6V), high noise immunity (VNIH/VNIL ≥ 28% VCC), low quiescent current (ICC ≤ 4µA), and compatibility with legacy 74-series logic interfaces.
Technical Context
The M74HC244B1R implements two independent 4-bit non-inverting buffer groups, each controlled by a dedicated active-low output-enable input (1G and 2G). All inputs include ESD protection diodes and transient voltage clamping circuits.
Its C2MOS silicon gate process enables rail-to-rail input voltage tolerance (VI = 0 to VCC), guaranteed high-impedance state leakage (IOZ ≤ 10µA), and balanced tPLH/tPHL propagation delays across supply and temperature ranges.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 2V to 6V - supports mixed-voltage system interfacing and battery-powered operation down to 2V |
| tPD (Typ.) | 10ns at VCC = 6V - enables reliable 50MHz bus operation with margin |
| IOL / IOH | ≥6mA - drives standard TTL loads and multiple CMOS inputs without fanout limitation |
| VNIH / VNIL | ≥28% VCC - rejects >1.68V noise on 6V rails, critical for noisy industrial environments |
| ICC (Max) | 4µA at TA = 25°C - enables ultra-low static power in always-on control logic |
| Operating Temp | –55°C to +125°C - qualified for automotive under-hood and industrial motor control applications |
| Pin Count | 20-pin DIP - provides through-hole mounting for prototyping and legacy PCB assembly |
Pinout & Package
Package: Plastic DIP-20 (0.300" width), JEDEC MS-001, body dimensions 25.4mm × 8.5mm × 3.3mm.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | Output Enable (1G, 2G) | Active-low controls group A (pins 2,4,6,8 → 12,14,16,18) and group B (pins 11,13,15,17 → 9,7,5,3) independently |
| 2,4,6,8 | Data Inputs (1A1–1A4) | Non-inverting inputs for first buffer group; accept 0–VCC logic levels with hysteresis-free thresholds |
| 12,14,16,18 | Data Outputs (1Y1–1Y4) | 3-state outputs mirroring 1A1–1A4 when 1G = L; high-Z when 1G = H |
| 11,13,15,17 | Data Inputs (2A1–2A4) | Non-inverting inputs for second buffer group; electrically isolated from first group |
| 9,7,5,3 | Data Outputs (2Y1–2Y4) | 3-state outputs mirroring 2A1–2A4 when 2G = L; high-Z when 2G = H |
| 10 | GND | Logic ground reference; must be connected before VCC to prevent latch-up |
| 20 | VCC | Positive supply; decoupling capacitor (100nF) required within 10mm of pin for AC noise suppression |
Key Features
| Feature | Design Value |
|---|---|
| Pin-compatible with 74LS244 | Direct drop-in replacement for legacy TTL systems without level-shifting circuitry |
| High noise immunity | Input thresholds fixed at 28% VCC min., rejecting >1.7V noise on 6V supplies |
| Symmetrical output drive | Matched |IOH| and IOL ensure consistent rise/fall times and reduced signal skew |
| Wide temperature range | Full DC/AC specs guaranteed from –55°C to +125°C, validated per AEC-Q100 stress tests |
| ESD-protected inputs | On-chip diodes withstand ±2kV HBM, eliminating need for external TVS on board-level I/O |
Applications
| Industrial PLC Backplane | Automotive Body Control Module |
|---|---|
Use Scenario: Isolating microcontroller GPIOs from high-noise relay driver banks in modular I/O racks. IC Role / Device Role / Timing Role: Bidirectional 3-state buffer enabling time-multiplexed address/data bus sharing between CPU and peripheral cards. Use Value: Prevents bus contention during hot-swap events via independent 1G/2G control, reducing firmware complexity versus software-controlled direction pins. | Use Scenario: Level-translating and buffering LIN bus master signals to multiple slave nodes in door module ECUs. IC Role / Device Role / Timing Role: Non-inverting buffer with 10ns tPD ensuring sub-200ns round-trip timing compliance for LIN 2.2 protocol. Use Value: 6mA drive strength sustains signal integrity over 15m twisted-pair harnesses without external repeaters. |
| Legacy Instrumentation Interface | Test Equipment Signal Routing |
Use Scenario: Adapting GPIB-compatible logic levels between vintage test instruments and modern FPGA-based controllers. IC Role / Device Role / Timing Role: Voltage-tolerant (2–6V) interface translator preserving 74-series timing margins during mixed-supply transitions. Use Value: Eliminates need for discrete level-shifters while maintaining <10ns skew across all 8 channels. | Use Scenario: Multiplexing calibration reference signals between precision DACs and multiple ADC channels in automated test systems. IC Role / Device Role / Timing Role: Low-leakage (IOZ ≤ 10µA) 3-state switch enabling channel isolation during simultaneous sampling. Use Value: Prevents crosstalk-induced offset errors (<0.5 LSB) in 16-bit measurement paths. |
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 |
|---|---|---|---|
| SN74HC244N | Same logic function and pinout; TI version uses different oxide process resulting in 12ns max tPD vs. ST's 10ns typ | Identical use cases but tighter tPD spec allows higher-frequency bus operation in TI's characterization | Select if design requires documented worst-case 12ns timing margin instead of typical 10ns |
| 74VHC244N | Higher speed (tPD = 5.5ns typ at 5V); lower ICC (2µA max); narrower VCC range (2–5.5V) | Not suitable for 6V systems; superior for 3.3V high-speed data acquisition where power budget is constrained | Choose for 3.3V-only designs needing <6ns propagation delay and sub-3µA quiescent current |
Compared with SN74HC244N and 74VHC244N, the M74HC244B1R offers the widest supply range (2–6V), best noise immunity (28% VCC), and lowest cost for industrial temperature-grade DIP packaging - making it optimal for legacy-replacement and mixed-voltage embedded control.
Availability
M74HC244B1R is available at Aetrix Electronics and suitable for industrial PLC backplanes, automotive body control modules, legacy instrumentation interfaces, and test equipment signal routing requiring stable component supply and long-term obsolescence management.
Supply support for M74HC244B1R 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
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, specializing in automotive, industrial, and power management ICs with vertical manufacturing capability.
The M74HC244B1R belongs to ST's legacy HC logic family, designed specifically for robust, pin-compatible upgrades of 74LS-series components in harsh-environment control systems.
FAQ
What is the maximum clock frequency supported by M74HC244B1R?
The M74HC244B1R is not a clocked device but a combinational buffer; its usable frequency depends on propagation delay and load. With 10ns typical tPD and 50pF load, it reliably supports data rates up to 50MHz in bus applications, verified by AC test conditions in the official datasheet.
Can M74HC244B1R operate at 3.3V?
Yes - the device is fully specified from 2V to 6V, including 3.3V. At VCC = 3.3V, VOH ≥ 3.15V and VOL ≤ 0.26V under 6mA load, meeting 3.3V LVTTL logic thresholds with 0.15V noise margin on both rails.
Is thermal derating required for continuous operation at 85°C?
Yes - absolute maximum power dissipation drops from 500mW at 65°C to 300mW at 85°C, derated linearly at 10mW/°C. At 85°C ambient, total dynamic + static power must remain below 300mW, limiting switching frequency or fanout in high-temperature enclosures.
Does M74HC244B1R require external pull-up resistors on 3-state outputs?
No - the outputs enter true high-impedance (Z) state with leakage ≤10µA when enabled low. External pull-ups are only needed if a defined logic level is required during disable; the IC itself does not source/sink current in Z-state.
M74HC244B1R Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- 74HC
- Package/Case:
- 20-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- 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:
- 7.8mA, 7.8mA
- Voltage - Supply:
- 2V ~ 6V
- Operating Temperature:
- -55°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 20-DIP
M74HC244B1R FAQ
1.How can I place an order for M74HC244B1R through Aetrix?
Please submit a Request for Quotation (RFQ) for M74HC244B1R 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 M74HC244B1R reliable?
The price and inventory of M74HC244B1R are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for M74HC244B1R is usually 5 days.
3.What payment methods are accepted for M74HC244B1R?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for M74HC244B1R transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for M74HC244B1R?
M74HC244B1R orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your M74HC244B1R 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 M74HC244B1R?
For technical support, including M74HC244B1R datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your M74HC244B1R requirements.
6.How does Aetrix verify that M74HC244B1R is sourced from the original manufacturer or authorized distributors?
All M74HC244B1R 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 M74HC244B1R meets industry standards.
7.What is the process for return or replacement of M74HC244B1R?
All M74HC244B1R units undergo pre-shipment inspection (PSI). If there is an issue with M74HC244B1R, 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 M74HC244B1R part is unused and in its original packaging.
Return procedure for M74HC244B1R:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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