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Texas Instruments SN74HCT244DWR
- Part No.:
- SN74HCT244DWR
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74HCT244DWR.pdf
- Description:
- IC BUF NON-INVERT 5.5V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:25,474
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Product details
Overview
SN74HCT244DWR from Texas Instruments is an octal 3-state noninverting buffer/line driver IC used for bus interfacing, memory address driving, and signal isolation in 5V TTL-compatible digital systems. It operates from 4.5V to 5.5V, delivers ±6mA output drive per channel, exhibits 13ns typical propagation delay at 5V/50pF, and supports high-impedance outputs for bidirectional bus control in servers and telecom infrastructure.
For engineers reviewing the SN74HCT244DWR datasheet, SN74HCT244DWR pinout, SN74HCT244DWR application, or SN74HCT244DWR equivalent, key selection criteria include its 20-pin SOIC (DW) package, dual 4-bit independent enable architecture, guaranteed 3-state behavior during power sequencing, and compatibility with LSTTL load levels up to 15 units.
Technical Context
The SN74HCT244DWR implements two independent 4-bit noninverting buffers, each with dedicated active-low output-enable (1OE, 2OE) inputs. When an OE input is low, corresponding A-inputs pass directly to Y-outputs; when high, all four outputs enter high-impedance state-enabling shared bus operation without contention.
Its HCT logic family ensures TTL-voltage-level compatibility (VIH = 2V min, VIL = 0.8V max at VCC = 4.5–5.5V), while CMOS input structure limits ICC to ≤80µA and input current to ≤1µA. Output drive capability of ±6mA at 5V supports direct connection to legacy LSTTL loads without external buffering.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply voltage | 4.5V to 5.5V - Ensures robust operation across industrial 5V rail tolerances and brown-out immunity. |
| Propagation delay (tpd) | 13ns typical at VCC = 5.5V, CL = 50pF - Enables reliable timing in high-speed address/data bus applications up to ~30 MHz. |
| Output drive | ±6mA per channel at VCC = 5V - Directly drives 15 LSTTL loads without fanout limitation or level-shifting. |
| Input compatibility | TTL-voltage compatible (VIH ≥ 2V, VIL ≤ 0.8V) - Interoperates seamlessly with legacy 5V TTL logic families. |
| Quiescent current (ICC) | ≤80µA maximum - Minimizes static power in always-on control and interface circuits. |
| 3-state enable time (ten) | 19ns max at VCC = 5.5V, CL = 50pF - Supports fast bus arbitration and dynamic resource sharing. |
| Input capacitance (Ci) | 10pF maximum - Reduces capacitive loading on upstream drivers and preserves signal integrity. |
Pinout & Package
SN74HCT244DWR is housed in a 20-pin SOIC (DW) package measuring 12.80mm × 10.3mm, with body size 12.8mm × 7.5mm. The package features gull-wing leads, RoHS-compliant NiPdAu finish, and MSL Level-1 rating (260°C peak reflow, unlimited floor life).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | 1OE, 2OE | Active-low output-enable controls for Group 1 (pins 2–9) and Group 2 (pins 11–18); enables independent bus segment control. |
| 2, 4, 6, 8 | 1A1–1A4 | Group 1 noninverting input channels - accept TTL-compatible signals for buffered transmission. |
| 3, 5, 7, 9 | 2Y4–2Y1 | Group 2 output channels (reversed pin order per TI convention) - drive downstream loads or bus lines. |
| 11, 13, 15, 17 | 2A1–2A4 | Group 2 noninverting input channels - operate independently from Group 1 with separate OE control. |
| 12, 14, 16, 18 | 1Y4–1Y1 | Group 1 output channels (reversed pin order) - provide isolated, 3-state buffered outputs for address/data buses. |
| 10 | GND | Ground reference for logic and power return - must be low-impedance and decoupled locally. |
| 20 | VCC | Positive supply terminal - requires 0.1µF ceramic bypass capacitor placed adjacent to pin. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent 4-bit groups | Enables simultaneous but isolated control of two bus segments using separate OE pins (1OE/2OE), reducing system-level arbitration complexity. |
| 3-state outputs with defined power-up behavior | Outputs remain high-impedance during power ramp if OE is pulled high - prevents bus contention at startup/shutdown. |
| TTL-compatible input thresholds | VIH ≥ 2V and VIL ≤ 0.8V at 5V supply ensure interoperability with legacy 74LS, 74ALS, and microcontroller GPIOs without level shifters. |
| Low ICC and II | ≤80µA ICC and ≤1µA input leakage minimize standby power and reduce loading on weak signal sources like pull-up networks. |
| High noise immunity | Typical VIH–VIL margin of 1.2V at 5V supply provides robust rejection of ground bounce and crosstalk in dense PCB layouts. |
Applications
| Server Memory Address Buffering | LED Display Column Driver Interface |
|---|---|
Use Scenario: Driving parallel address lines from a CPU or memory controller to multiple DRAM banks in a rack-mounted server. IC Role / Device Role / Timing Role: Noninverting 3-state buffer isolating address bus segments; enables bank-select multiplexing without contention. Use Value: ±6mA drive sustains signal integrity across 15cm+ PCB traces; 13ns tpd meets DDR2/DDR3 address setup timing budgets. |
Use Scenario: Interfacing a microcontroller's parallel port to the column drivers of a 16×16 LED matrix display. IC Role / Device Role / Timing Role: Level-translating and fanout buffer between MCU GPIOs and high-current LED sink drivers. Use Value: TTL-compatible inputs accept 3.3V/5V MCU outputs directly; 3-state outputs allow dynamic column scanning without ghosting. |
| Industrial Network Switch Backplane Interface | Motor Driver Control Signal Isolation |
Use Scenario: Isolating control signals (e.g., reset, clock enable, mode select) between ASICs and PHYs on a 10G Ethernet switch backplane. IC Role / Device Role / Timing Role: Bidirectional bus buffer with independent group enables - separates management and data path signaling domains. Use Value: Dual OE architecture permits asynchronous enable/disable of control vs. status lines; low ICC reduces thermal load in sealed chassis. |
Use Scenario: Conditioning PWM and direction signals from a motion controller before routing to H-bridge gate drivers in a servo amplifier. IC Role / Device Role / Timing Role: Noise-immune signal repeater with defined 3-state behavior during fault shutdown sequences. Use Value: High VIH threshold rejects EMI-induced glitches; 3-state outputs prevent unintended motor activation during controller reset. |
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 |
|---|---|---|---|
| SN74HCT244NSR | Same logic function and electrical specs, but in 20-pin SOP (NS) package (12.6mm × 7.8mm body); slightly smaller footprint than DW. | Suitable for space-constrained designs where SOIC lead pitch (1.27mm) is acceptable but overall board area must be minimized. | Select SN74HCT244NSR when layout density is prioritized over thermal performance - SOP has higher RθJA (113.4°C/W) than SOIC (109.1°C/W). |
| SN74HCT244PW | Identical functionality in 20-pin TSSOP (PW) package (6.5mm × 6.4mm); significantly smaller footprint and lower profile than SOIC. | Preferred for portable or ultra-thin industrial controllers where Z-height and PCB real estate are critical constraints. | Choose SN74HCT244PW only if assembly process supports fine-pitch TSSOP (0.65mm pitch) and thermal derating is verified - RθJA = 131.8°C/W. |
Compared with SN74HCT244NSR and SN74HCT244PW, the SN74HCT244DWR offers the best balance of manufacturability (standard SOIC reflow profile), thermal performance (lowest RθJA among surface-mount variants), and mechanical robustness - making it ideal for high-reliability industrial and telecom equipment.
Availability
SN74HCT244DWR is available at Aetrix Electronics and suitable for servers, LED displays, network switches, and motor drivers requiring stable component supply across extended temperature ranges (–40°C to +125°C) and long production lifecycles.
Supply support for SN74HCT244DWR 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 leader specializing in analog, embedded processing, and logic solutions, with decades of heritage in industry-standard logic families.
The SN74HCT244 series belongs to TI's HCT (High-Speed CMOS TTL-compatible) logic portfolio, designed specifically for seamless replacement of legacy 74LS devices in 5V systems while delivering lower power and improved noise margins.
FAQ
What is the operating temperature range for SN74HCT244DWR?
The SN74HCT244DWR is rated for operation from –40°C to +125°C. This extended industrial temperature range is confirmed in TI's official orderable addendum and applies to all active DW-package variants including SN74HCT244DWR and SN74HCT244DWR.A. The device maintains full electrical specifications across this range per its Recommended Operating Conditions table.
Does SN74HCT244DWR support true 3-state behavior during power-up?
Yes - the SN74HCT244DWR outputs enter high-impedance state when either 1OE or 2OE is high. To guarantee defined 3-state behavior during power ramp, TI recommends tying OE pins to VCC via a pullup resistor; the minimum value depends on the driver's current-sinking capability, as specified in the Functional Modes section of the SN74HCT244 datasheet.
Can SN74HCT244DWR drive standard LSTTL loads directly?
Yes - the SN74HCT244DWR is explicitly characterized to drive up to 15 LSTTL loads per output, as stated in its Features list and validated by its ±6mA output drive specification at 5V. This eliminates the need for additional buffer stages when interfacing with legacy 74LS-series logic or discrete transistor-based loads.
What is the maximum clock/data rate supported by SN74HCT244DWR?
The SN74HCT244DWR does not operate on a clock; it is a combinatorial buffer. Its usable data rate is determined by propagation delay (13ns typical) and rise/fall times (7–12ns). At 5.5V/50pF, it reliably supports bus toggle rates up to ~30 MHz in point-to-point configurations, assuming proper termination and layout practices per TI's Application and Implementation guidelines.
Is SN74HCT244DWR pin-compatible with other SN74HCT244 package variants?
Yes - all SN74HCT244 variants (DB, DGS, DW, N, NS, PW) share identical pin configuration and function mapping per TI's Pin Configuration and Functions table. The SN74HCT244DWR (SOIC) uses the same 20-pin numbering and signal assignment as SN74HCT244NSR (SOP) and SN74HCT244PW (TSSOP), enabling drop-in substitution where package footprint and thermal requirements permit.
SN74HCT244DWR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HCT
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- 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:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
SN74HCT244DWR FAQ
1.How can I place an order for SN74HCT244DWR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74HCT244DWR 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 SN74HCT244DWR reliable?
The price and inventory of SN74HCT244DWR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74HCT244DWR is usually 5 days.
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4.How is shipping managed for SN74HCT244DWR?
SN74HCT244DWR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74HCT244DWR 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 SN74HCT244DWR?
For technical support, including SN74HCT244DWR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74HCT244DWR requirements.
6.How does Aetrix verify that SN74HCT244DWR is sourced from the original manufacturer or authorized distributors?
All SN74HCT244DWR 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 SN74HCT244DWR meets industry standards.
7.What is the process for return or replacement of SN74HCT244DWR?
All SN74HCT244DWR units undergo pre-shipment inspection (PSI). If there is an issue with SN74HCT244DWR, 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 SN74HCT244DWR part is unused and in its original packaging.
Return procedure for SN74HCT244DWR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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