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Texas Instruments SN74HCT244AN
- Part No.:
- SN74HCT244AN
- Manufacturer:
- Texas Instruments
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
SN74HCT244AN.pdf
- Description:
- IC BUFFER NON-INVERT 5.5V 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:6,840
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Product details
Overview
SN74HCT244AN from Texas Instruments is an octal non-inverting 3-state buffer/line driver with TTL-compatible inputs, designed for bidirectional bus interfacing in automotive and industrial control systems. It features two independent 4-bit sections (1A/1Y and 2A/2Y), dual active-low output enables (1OE, 2OE), operates at 4.5–5.5 V, and is qualified to AEC-Q100 Grade 1 (−40 °C to +125 °C).
For engineers reviewing the SN74HCT244AN datasheet, SN74HCT244AN pinout, SN74HCT244AN application, or SN74HCT244AN equivalent, key selection criteria include its TTL-level input compatibility, 3-state bus isolation capability, −40 °C to +125 °C automotive temperature range, and SOIC-20 package footprint compatibility with legacy 74-series logic designs.
Technical Context
The SN74HCT244AN implements dual 4-bit non-inverting buffer sections with independent 3-state control: 1OE governs outputs 1Y0–1Y3, and 2OE governs 2Y0–2Y3. Each output drives up to ±6 mA at VCC = 4.5 V while maintaining TTL input thresholds (VIH = 2.0 V min, VIL = 0.8 V max).
Its architecture supports bus hold-off during enable transitions, with disable time (tdis) ≤ 38 ns and enable time (ten) ≤ 45 ns at 125 °C, ensuring clean signal gating in high-speed digital subsystems. Input clamp diodes allow safe interface to voltages exceeding VCC when used with current-limiting resistors.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | HCT - TTL-compatible input thresholds ensure direct replacement of 74LS devices without level-shifting. |
| Supply Voltage | 4.5 V to 5.5 V - Matches standard 5 V automotive and industrial rails; not rated below 4.5 V. |
| Output Drive | ±6 mA (VCC = 4.5 V) - Sufficient to drive 50 Ω transmission lines or fan-out to ≥10 LS-TTL loads. |
| Propagation Delay | 11 ns typ (VCC = 4.5 V, CL = 15 pF) - Enables reliable operation in sub-40 MHz bus timing budgets. |
| Temperature Range | −40 °C to +125 °C - AEC-Q100 Grade 1 qualification confirms suitability for under-hood automotive ECUs. |
| ESD Protection | HBM > 2000 V - Robust handling during PCB assembly and field service without special ESD precautions. |
| Input Capacitance | 3.5 pF - Low loading minimizes signal distortion on high-impedance or long-trace control lines. |
Pinout & Package
SN74HCT244AN is supplied in a plastic small outline IC (SOIC-20) package with 20 leads, 7.5 mm body width, and standard 1.27 mm lead pitch (JEDEC MS-013). Pin 1 is marked by a notch or dot; the package is RoHS-compliant and Pb-free.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | 1OE, 2OE | Active-low output enable inputs - Pull LOW to activate respective 4-bit output group; HIGH places outputs in high-impedance state. |
| 2, 4, 6, 8 | 1A0–1A3 | Section 1 data inputs - Non-inverting inputs driving outputs 1Y0–1Y3 when 1OE = LOW. |
| 3, 5, 7, 9 | 2Y0–2Y3 | Section 2 outputs - Driven by 2A0–2A3 when 2OE = LOW; tri-stated otherwise. |
| 10 | GND | Ground reference - Must be connected to system 0 V plane; serves as return path for all I/O and supply currents. |
| 11, 13, 15, 17 | 2A0–2A3 | Section 2 data inputs - Non-inverting inputs driving outputs 2Y0–2Y3 when 2OE = LOW. |
| 12, 14, 16, 18 | 1Y0–1Y3 | Section 1 outputs - Driven by 1A0–1A3 when 1OE = LOW; tri-stated otherwise. |
| 20 | VCC | Positive supply - Connect to regulated 4.5–5.5 V rail; bypass with 0.1 µF ceramic capacitor near pin. |
Key Features
| Feature | Design Value |
|---|---|
| TTL-compatible inputs | VIH = 2.0 V min, VIL = 0.8 V max at VCC = 4.5–5.5 V - Eliminates need for external level shifters when interfacing with legacy 74LS or microcontroller GPIOs. |
| Dual independent 3-state control | Separate 1OE and 2OE pins - Enables selective isolation of two 4-bit data paths on shared buses without software coordination. |
| Automotive qualification | AEC-Q100 Grade 1 (−40 °C to +125 °C) - Validated for engine control, body electronics, and ADAS modules requiring extended thermal reliability. |
| Input clamp diodes | Integrated protection on all inputs - Permits safe connection to signals up to VCC + 0.5 V using series current-limiting resistors. |
| Low dynamic power | CPD = 35 pF per buffer - Reduces switching current draw and heat generation in high-frequency bus applications. |
Applications
| Automotive Body Control Module | Industrial PLC I/O Expansion |
|---|---|
|
Use Scenario: Isolating microcontroller GPIOs from high-current solenoid drivers and sensor inputs in vehicle door modules. IC Role / Device Role / Timing Role: Bidirectional bus buffer enabling safe signal routing between MCU and peripheral drivers while preventing backfeed during reset or fault conditions. Use Value: Dual OE control allows independent enable/disable of interior light and window motor control lines, reducing software overhead and eliminating cross-talk. |
Use Scenario: Extending parallel I/O capacity of a programmable logic controller CPU board via ribbon-cable-connected daughter cards. IC Role / Device Role / Timing Role: 3-state line driver providing noise-immune, slew-rate-controlled data transfer between main CPU and remote I/O banks. Use Value: 11 ns propagation delay ensures deterministic timing across 20 cm backplane traces, supporting scan rates up to 30 kHz. |
| Automotive Instrument Cluster | Test Equipment Digital Pattern Generator |
|
Use Scenario: Driving multiplexed LED segment displays and CAN transceiver control lines from a low-power MCU in dashboard assemblies. IC Role / Device Role / Timing Role: Level-translating buffer converting 3.3 V MCU outputs to robust 5 V logic levels compatible with display drivers and transceivers. Use Value: TTL input compatibility eliminates external voltage translators, reducing BOM count and layout area in space-constrained instrument clusters. |
Use Scenario: Generating synchronized 8-bit stimulus patterns for DUT testing in automated test equipment (ATE) racks. IC Role / Device Role / Timing Role: Precision-timed buffer isolating pattern generator FPGA outputs from variable capacitive loads of test fixtures. Use Value: 35 pF CPD and <38 ns tdis guarantee stable edge integrity into 50 pF loads, meeting JEDEC JESD68B waveform fidelity requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HCT244N | Same logic function and pinout, but commercial-grade (0 °C to +70 °C); no AEC-Q100 qualification. | Suitable only for non-automotive industrial or lab equipment where extended temperature is not required. | Select SN74HCT244N for cost-sensitive non-automotive designs where Grade 1 qualification is unnecessary. |
| 74HCT244D-Q100 | Identical electrical specs and AEC-Q100 Grade 1 rating, but in SO20 package with different moisture sensitivity level (MSL 3 vs MSL 1 for SN74HCT244AN). | Requires requalification for reflow profile due to differing package thermal mass and MSL classification. | Choose 74HCT244D-Q100 only if sourcing constraints require NXP-branded equivalents with identical automotive qualification. |
Compared with SN74HCT244N, the SN74HCT244AN provides guaranteed operation at −40 °C to +125 °C and automotive qualification; compared with 74HCT244D-Q100, it offers MSL 1 handling and TI-specific packaging logistics, simplifying high-volume manufacturing flow.
Availability
SN74HCT244AN is available at Aetrix Electronics and suitable for automotive body control modules, industrial PLC I/O expansion, instrument cluster interfaces, and test equipment pattern generation requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for SN74HCT244AN 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
Texas Instruments is a global semiconductor company specializing in analog, embedded processing, and logic solutions, with leadership in automotive, industrial, and communications markets.
The SN74HCT244AN belongs to TI's 74HCT logic family, engineered for TTL-to-CMOS interfacing in harsh-environment applications where reliability, consistent timing, and wide operating temperature are critical.
FAQ
What is the maximum operating temperature for SN74HCT244AN?
The SN74HCT244AN is qualified to AEC-Q100 Grade 1, with a specified operating ambient temperature range of −40 °C to +125 °C. This rating is validated across all electrical parameters in the datasheet and applies to the SOIC-20 package variant. Operation beyond +125 °C is not guaranteed and may result in parametric degradation or failure.
Does SN74HCT244AN support 3.3 V logic inputs?
No, SN74HCT244AN does not reliably accept 3.3 V logic inputs. Its TTL-compatible input thresholds require VIH ≥ 2.0 V (min) and VIL ≤ 0.8 V (max) at VCC = 4.5–5.5 V. A 3.3 V HIGH signal falls below the guaranteed VIH level and may cause inconsistent switching or increased static current. Use a level shifter or HCT-family device with 3.3 V–tolerant inputs if interfacing with 3.3 V systems.
Can SN74HCT244AN drive a 50 Ω transmission line directly?
Yes, SN74HCT244AN can drive a 50 Ω load: at VCC = 4.5 V, its VOH is ≥3.7 V and VOL is ≤0.4 V with IO = ±6 mA, satisfying standard 5 V logic swing requirements into 50 Ω. However, for optimal signal integrity over >10 cm traces, add series termination (e.g., 33 Ω) at the driver output to suppress reflections - the SN74HCT244AN's 11 ns tpd supports this configuration.
Is SN74HCT244AN pin-compatible with SN74LS244?
Yes, SN74HCT244AN is pin-compatible with SN74LS244 in SOIC-20 packages, sharing identical pin numbering, function mapping, and 20-pin footprint. However, SN74HCT244AN draws significantly less quiescent current (ICC < 160 µA vs ~25 mA for LS244) and offers higher noise immunity, making it a direct drop-in upgrade for power-sensitive or high-reliability applications.
What is the purpose of the input clamp diodes in SN74HCT244AN?
The input clamp diodes in SN74HCT244AN protect against overvoltage transients by shunting currents exceeding VCC + 0.5 V or falling below GND − 0.5 V to the supply rails. When used with external current-limiting resistors (e.g., 1 kΩ), they enable safe interfacing to signals operating at voltages above VCC - such as 12 V sensor outputs or hot-swap control lines - without damaging the IC.
SN74HCT244AN Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HCT
- Package/Case:
- 20-DIP (0.300", 7.62mm)
- 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:
- 6mA, 6mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 20-PDIP
SN74HCT244AN FAQ
1.How can I place an order for SN74HCT244AN through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74HCT244AN 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 SN74HCT244AN reliable?
The price and inventory of SN74HCT244AN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74HCT244AN is usually 5 days.
3.What payment methods are accepted for SN74HCT244AN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74HCT244AN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74HCT244AN?
SN74HCT244AN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74HCT244AN 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 SN74HCT244AN?
For technical support, including SN74HCT244AN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74HCT244AN requirements.
6.How does Aetrix verify that SN74HCT244AN is sourced from the original manufacturer or authorized distributors?
All SN74HCT244AN 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 SN74HCT244AN meets industry standards.
7.What is the process for return or replacement of SN74HCT244AN?
All SN74HCT244AN units undergo pre-shipment inspection (PSI). If there is an issue with SN74HCT244AN, 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 SN74HCT244AN part is unused and in its original packaging.
Return procedure for SN74HCT244AN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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